diff options
Diffstat (limited to 'gcc-4.2.1-5666.3/gcc/lambda-code.c')
| -rw-r--r-- | gcc-4.2.1-5666.3/gcc/lambda-code.c | 2708 |
1 files changed, 2708 insertions, 0 deletions
diff --git a/gcc-4.2.1-5666.3/gcc/lambda-code.c b/gcc-4.2.1-5666.3/gcc/lambda-code.c new file mode 100644 index 000000000..2a8a5463e --- /dev/null +++ b/gcc-4.2.1-5666.3/gcc/lambda-code.c @@ -0,0 +1,2708 @@ +/* Loop transformation code generation + Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc. + Contributed by Daniel Berlin <dberlin@dberlin.org> + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify it under + the terms of the GNU General Public License as published by the Free + Software Foundation; either version 2, or (at your option) any later + version. + + GCC is distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING. If not, write to the Free + Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA + 02110-1301, USA. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "ggc.h" +#include "tree.h" +#include "target.h" +#include "rtl.h" +#include "basic-block.h" +#include "diagnostic.h" +#include "tree-flow.h" +#include "tree-dump.h" +#include "timevar.h" +#include "cfgloop.h" +#include "expr.h" +#include "optabs.h" +#include "tree-chrec.h" +#include "tree-data-ref.h" +#include "tree-pass.h" +#include "tree-scalar-evolution.h" +#include "vec.h" +#include "lambda.h" +#include "vecprim.h" + +/* This loop nest code generation is based on non-singular matrix + math. + + A little terminology and a general sketch of the algorithm. See "A singular + loop transformation framework based on non-singular matrices" by Wei Li and + Keshav Pingali for formal proofs that the various statements below are + correct. + + A loop iteration space represents the points traversed by the loop. A point in the + iteration space can be represented by a vector of size <loop depth>. You can + therefore represent the iteration space as an integral combinations of a set + of basis vectors. + + A loop iteration space is dense if every integer point between the loop + bounds is a point in the iteration space. Every loop with a step of 1 + therefore has a dense iteration space. + + for i = 1 to 3, step 1 is a dense iteration space. + + A loop iteration space is sparse if it is not dense. That is, the iteration + space skips integer points that are within the loop bounds. + + for i = 1 to 3, step 2 is a sparse iteration space, because the integer point + 2 is skipped. + + Dense source spaces are easy to transform, because they don't skip any + points to begin with. Thus we can compute the exact bounds of the target + space using min/max and floor/ceil. + + For a dense source space, we take the transformation matrix, decompose it + into a lower triangular part (H) and a unimodular part (U). + We then compute the auxiliary space from the unimodular part (source loop + nest . U = auxiliary space) , which has two important properties: + 1. It traverses the iterations in the same lexicographic order as the source + space. + 2. It is a dense space when the source is a dense space (even if the target + space is going to be sparse). + + Given the auxiliary space, we use the lower triangular part to compute the + bounds in the target space by simple matrix multiplication. + The gaps in the target space (IE the new loop step sizes) will be the + diagonals of the H matrix. + + Sparse source spaces require another step, because you can't directly compute + the exact bounds of the auxiliary and target space from the sparse space. + Rather than try to come up with a separate algorithm to handle sparse source + spaces directly, we just find a legal transformation matrix that gives you + the sparse source space, from a dense space, and then transform the dense + space. + + For a regular sparse space, you can represent the source space as an integer + lattice, and the base space of that lattice will always be dense. Thus, we + effectively use the lattice to figure out the transformation from the lattice + base space, to the sparse iteration space (IE what transform was applied to + the dense space to make it sparse). We then compose this transform with the + transformation matrix specified by the user (since our matrix transformations + are closed under composition, this is okay). We can then use the base space + (which is dense) plus the composed transformation matrix, to compute the rest + of the transform using the dense space algorithm above. + + In other words, our sparse source space (B) is decomposed into a dense base + space (A), and a matrix (L) that transforms A into B, such that A.L = B. + We then compute the composition of L and the user transformation matrix (T), + so that T is now a transform from A to the result, instead of from B to the + result. + IE A.(LT) = result instead of B.T = result + Since A is now a dense source space, we can use the dense source space + algorithm above to compute the result of applying transform (LT) to A. + + Fourier-Motzkin elimination is used to compute the bounds of the base space + of the lattice. */ + +static bool perfect_nestify (struct loops *, + struct loop *, VEC(tree,heap) *, + VEC(tree,heap) *, VEC(int,heap) *, + VEC(tree,heap) *); +/* Lattice stuff that is internal to the code generation algorithm. */ + +typedef struct +{ + /* Lattice base matrix. */ + lambda_matrix base; + /* Lattice dimension. */ + int dimension; + /* Origin vector for the coefficients. */ + lambda_vector origin; + /* Origin matrix for the invariants. */ + lambda_matrix origin_invariants; + /* Number of invariants. */ + int invariants; +} *lambda_lattice; + +#define LATTICE_BASE(T) ((T)->base) +#define LATTICE_DIMENSION(T) ((T)->dimension) +#define LATTICE_ORIGIN(T) ((T)->origin) +#define LATTICE_ORIGIN_INVARIANTS(T) ((T)->origin_invariants) +#define LATTICE_INVARIANTS(T) ((T)->invariants) + +static bool lle_equal (lambda_linear_expression, lambda_linear_expression, + int, int); +static lambda_lattice lambda_lattice_new (int, int); +static lambda_lattice lambda_lattice_compute_base (lambda_loopnest); + +static tree find_induction_var_from_exit_cond (struct loop *); +static bool can_convert_to_perfect_nest (struct loop *); + +/* Create a new lambda body vector. */ + +lambda_body_vector +lambda_body_vector_new (int size) +{ + lambda_body_vector ret; + + ret = ggc_alloc (sizeof (*ret)); + LBV_COEFFICIENTS (ret) = lambda_vector_new (size); + LBV_SIZE (ret) = size; + LBV_DENOMINATOR (ret) = 1; + return ret; +} + +/* Compute the new coefficients for the vector based on the + *inverse* of the transformation matrix. */ + +lambda_body_vector +lambda_body_vector_compute_new (lambda_trans_matrix transform, + lambda_body_vector vect) +{ + lambda_body_vector temp; + int depth; + + /* Make sure the matrix is square. */ + gcc_assert (LTM_ROWSIZE (transform) == LTM_COLSIZE (transform)); + + depth = LTM_ROWSIZE (transform); + + temp = lambda_body_vector_new (depth); + LBV_DENOMINATOR (temp) = + LBV_DENOMINATOR (vect) * LTM_DENOMINATOR (transform); + lambda_vector_matrix_mult (LBV_COEFFICIENTS (vect), depth, + LTM_MATRIX (transform), depth, + LBV_COEFFICIENTS (temp)); + LBV_SIZE (temp) = LBV_SIZE (vect); + return temp; +} + +/* Print out a lambda body vector. */ + +void +print_lambda_body_vector (FILE * outfile, lambda_body_vector body) +{ + print_lambda_vector (outfile, LBV_COEFFICIENTS (body), LBV_SIZE (body)); +} + +/* Return TRUE if two linear expressions are equal. */ + +static bool +lle_equal (lambda_linear_expression lle1, lambda_linear_expression lle2, + int depth, int invariants) +{ + int i; + + if (lle1 == NULL || lle2 == NULL) + return false; + if (LLE_CONSTANT (lle1) != LLE_CONSTANT (lle2)) + return false; + if (LLE_DENOMINATOR (lle1) != LLE_DENOMINATOR (lle2)) + return false; + for (i = 0; i < depth; i++) + if (LLE_COEFFICIENTS (lle1)[i] != LLE_COEFFICIENTS (lle2)[i]) + return false; + for (i = 0; i < invariants; i++) + if (LLE_INVARIANT_COEFFICIENTS (lle1)[i] != + LLE_INVARIANT_COEFFICIENTS (lle2)[i]) + return false; + return true; +} + +/* Create a new linear expression with dimension DIM, and total number + of invariants INVARIANTS. */ + +lambda_linear_expression +lambda_linear_expression_new (int dim, int invariants) +{ + lambda_linear_expression ret; + + ret = ggc_alloc_cleared (sizeof (*ret)); + + LLE_COEFFICIENTS (ret) = lambda_vector_new (dim); + LLE_CONSTANT (ret) = 0; + LLE_INVARIANT_COEFFICIENTS (ret) = lambda_vector_new (invariants); + LLE_DENOMINATOR (ret) = 1; + LLE_NEXT (ret) = NULL; + + return ret; +} + +/* Print out a linear expression EXPR, with SIZE coefficients, to OUTFILE. + The starting letter used for variable names is START. */ + +static void +print_linear_expression (FILE * outfile, lambda_vector expr, int size, + char start) +{ + int i; + bool first = true; + for (i = 0; i < size; i++) + { + if (expr[i] != 0) + { + if (first) + { + if (expr[i] < 0) + fprintf (outfile, "-"); + first = false; + } + else if (expr[i] > 0) + fprintf (outfile, " + "); + else + fprintf (outfile, " - "); + if (abs (expr[i]) == 1) + fprintf (outfile, "%c", start + i); + else + fprintf (outfile, "%d%c", abs (expr[i]), start + i); + } + } +} + +/* Print out a lambda linear expression structure, EXPR, to OUTFILE. The + depth/number of coefficients is given by DEPTH, the number of invariants is + given by INVARIANTS, and the character to start variable names with is given + by START. */ + +void +print_lambda_linear_expression (FILE * outfile, + lambda_linear_expression expr, + int depth, int invariants, char start) +{ + fprintf (outfile, "\tLinear expression: "); + print_linear_expression (outfile, LLE_COEFFICIENTS (expr), depth, start); + fprintf (outfile, " constant: %d ", LLE_CONSTANT (expr)); + fprintf (outfile, " invariants: "); + print_linear_expression (outfile, LLE_INVARIANT_COEFFICIENTS (expr), + invariants, 'A'); + fprintf (outfile, " denominator: %d\n", LLE_DENOMINATOR (expr)); +} + +/* Print a lambda loop structure LOOP to OUTFILE. The depth/number of + coefficients is given by DEPTH, the number of invariants is + given by INVARIANTS, and the character to start variable names with is given + by START. */ + +void +print_lambda_loop (FILE * outfile, lambda_loop loop, int depth, + int invariants, char start) +{ + int step; + lambda_linear_expression expr; + + gcc_assert (loop); + + expr = LL_LINEAR_OFFSET (loop); + step = LL_STEP (loop); + fprintf (outfile, " step size = %d \n", step); + + if (expr) + { + fprintf (outfile, " linear offset: \n"); + print_lambda_linear_expression (outfile, expr, depth, invariants, + start); + } + + fprintf (outfile, " lower bound: \n"); + for (expr = LL_LOWER_BOUND (loop); expr != NULL; expr = LLE_NEXT (expr)) + print_lambda_linear_expression (outfile, expr, depth, invariants, start); + fprintf (outfile, " upper bound: \n"); + for (expr = LL_UPPER_BOUND (loop); expr != NULL; expr = LLE_NEXT (expr)) + print_lambda_linear_expression (outfile, expr, depth, invariants, start); +} + +/* Create a new loop nest structure with DEPTH loops, and INVARIANTS as the + number of invariants. */ + +lambda_loopnest +lambda_loopnest_new (int depth, int invariants) +{ + lambda_loopnest ret; + ret = ggc_alloc (sizeof (*ret)); + + LN_LOOPS (ret) = ggc_alloc_cleared (depth * sizeof (lambda_loop)); + LN_DEPTH (ret) = depth; + LN_INVARIANTS (ret) = invariants; + + return ret; +} + +/* Print a lambda loopnest structure, NEST, to OUTFILE. The starting + character to use for loop names is given by START. */ + +void +print_lambda_loopnest (FILE * outfile, lambda_loopnest nest, char start) +{ + int i; + for (i = 0; i < LN_DEPTH (nest); i++) + { + fprintf (outfile, "Loop %c\n", start + i); + print_lambda_loop (outfile, LN_LOOPS (nest)[i], LN_DEPTH (nest), + LN_INVARIANTS (nest), 'i'); + fprintf (outfile, "\n"); + } +} + +/* Allocate a new lattice structure of DEPTH x DEPTH, with INVARIANTS number + of invariants. */ + +static lambda_lattice +lambda_lattice_new (int depth, int invariants) +{ + lambda_lattice ret; + ret = ggc_alloc (sizeof (*ret)); + LATTICE_BASE (ret) = lambda_matrix_new (depth, depth); + LATTICE_ORIGIN (ret) = lambda_vector_new (depth); + LATTICE_ORIGIN_INVARIANTS (ret) = lambda_matrix_new (depth, invariants); + LATTICE_DIMENSION (ret) = depth; + LATTICE_INVARIANTS (ret) = invariants; + return ret; +} + +/* Compute the lattice base for NEST. The lattice base is essentially a + non-singular transform from a dense base space to a sparse iteration space. + We use it so that we don't have to specially handle the case of a sparse + iteration space in other parts of the algorithm. As a result, this routine + only does something interesting (IE produce a matrix that isn't the + identity matrix) if NEST is a sparse space. */ + +static lambda_lattice +lambda_lattice_compute_base (lambda_loopnest nest) +{ + lambda_lattice ret; + int depth, invariants; + lambda_matrix base; + + int i, j, step; + lambda_loop loop; + lambda_linear_expression expression; + + depth = LN_DEPTH (nest); + invariants = LN_INVARIANTS (nest); + + ret = lambda_lattice_new (depth, invariants); + base = LATTICE_BASE (ret); + for (i = 0; i < depth; i++) + { + loop = LN_LOOPS (nest)[i]; + gcc_assert (loop); + step = LL_STEP (loop); + /* If we have a step of 1, then the base is one, and the + origin and invariant coefficients are 0. */ + if (step == 1) + { + for (j = 0; j < depth; j++) + base[i][j] = 0; + base[i][i] = 1; + LATTICE_ORIGIN (ret)[i] = 0; + for (j = 0; j < invariants; j++) + LATTICE_ORIGIN_INVARIANTS (ret)[i][j] = 0; + } + else + { + /* Otherwise, we need the lower bound expression (which must + be an affine function) to determine the base. */ + expression = LL_LOWER_BOUND (loop); + gcc_assert (expression && !LLE_NEXT (expression) + && LLE_DENOMINATOR (expression) == 1); + + /* The lower triangular portion of the base is going to be the + coefficient times the step */ + for (j = 0; j < i; j++) + base[i][j] = LLE_COEFFICIENTS (expression)[j] + * LL_STEP (LN_LOOPS (nest)[j]); + base[i][i] = step; + for (j = i + 1; j < depth; j++) + base[i][j] = 0; + + /* Origin for this loop is the constant of the lower bound + expression. */ + LATTICE_ORIGIN (ret)[i] = LLE_CONSTANT (expression); + + /* Coefficient for the invariants are equal to the invariant + coefficients in the expression. */ + for (j = 0; j < invariants; j++) + LATTICE_ORIGIN_INVARIANTS (ret)[i][j] = + LLE_INVARIANT_COEFFICIENTS (expression)[j]; + } + } + return ret; +} + +/* Compute the least common multiple of two numbers A and B . */ + +static int +lcm (int a, int b) +{ + return (abs (a) * abs (b) / gcd (a, b)); +} + +/* Perform Fourier-Motzkin elimination to calculate the bounds of the + auxiliary nest. + Fourier-Motzkin is a way of reducing systems of linear inequalities so that + it is easy to calculate the answer and bounds. + A sketch of how it works: + Given a system of linear inequalities, ai * xj >= bk, you can always + rewrite the constraints so they are all of the form + a <= x, or x <= b, or x >= constant for some x in x1 ... xj (and some b + in b1 ... bk, and some a in a1...ai) + You can then eliminate this x from the non-constant inequalities by + rewriting these as a <= b, x >= constant, and delete the x variable. + You can then repeat this for any remaining x variables, and then we have + an easy to use variable <= constant (or no variables at all) form that we + can construct our bounds from. + + In our case, each time we eliminate, we construct part of the bound from + the ith variable, then delete the ith variable. + + Remember the constant are in our vector a, our coefficient matrix is A, + and our invariant coefficient matrix is B. + + SIZE is the size of the matrices being passed. + DEPTH is the loop nest depth. + INVARIANTS is the number of loop invariants. + A, B, and a are the coefficient matrix, invariant coefficient, and a + vector of constants, respectively. */ + +static lambda_loopnest +compute_nest_using_fourier_motzkin (int size, + int depth, + int invariants, + lambda_matrix A, + lambda_matrix B, + lambda_vector a) +{ + + int multiple, f1, f2; + int i, j, k; + lambda_linear_expression expression; + lambda_loop loop; + lambda_loopnest auxillary_nest; + lambda_matrix swapmatrix, A1, B1; + lambda_vector swapvector, a1; + int newsize; + + A1 = lambda_matrix_new (128, depth); + B1 = lambda_matrix_new (128, invariants); + a1 = lambda_vector_new (128); + + auxillary_nest = lambda_loopnest_new (depth, invariants); + + for (i = depth - 1; i >= 0; i--) + { + loop = lambda_loop_new (); + LN_LOOPS (auxillary_nest)[i] = loop; + LL_STEP (loop) = 1; + + for (j = 0; j < size; j++) + { + if (A[j][i] < 0) + { + /* Any linear expression in the matrix with a coefficient less + than 0 becomes part of the new lower bound. */ + expression = lambda_linear_expression_new (depth, invariants); + + for (k = 0; k < i; k++) + LLE_COEFFICIENTS (expression)[k] = A[j][k]; + + for (k = 0; k < invariants; k++) + LLE_INVARIANT_COEFFICIENTS (expression)[k] = -1 * B[j][k]; + + LLE_DENOMINATOR (expression) = -1 * A[j][i]; + LLE_CONSTANT (expression) = -1 * a[j]; + + /* Ignore if identical to the existing lower bound. */ + if (!lle_equal (LL_LOWER_BOUND (loop), + expression, depth, invariants)) + { + LLE_NEXT (expression) = LL_LOWER_BOUND (loop); + LL_LOWER_BOUND (loop) = expression; + } + + } + else if (A[j][i] > 0) + { + /* Any linear expression with a coefficient greater than 0 + becomes part of the new upper bound. */ + expression = lambda_linear_expression_new (depth, invariants); + for (k = 0; k < i; k++) + LLE_COEFFICIENTS (expression)[k] = -1 * A[j][k]; + + for (k = 0; k < invariants; k++) + LLE_INVARIANT_COEFFICIENTS (expression)[k] = B[j][k]; + + LLE_DENOMINATOR (expression) = A[j][i]; + LLE_CONSTANT (expression) = a[j]; + + /* Ignore if identical to the existing upper bound. */ + if (!lle_equal (LL_UPPER_BOUND (loop), + expression, depth, invariants)) + { + LLE_NEXT (expression) = LL_UPPER_BOUND (loop); + LL_UPPER_BOUND (loop) = expression; + } + + } + } + + /* This portion creates a new system of linear inequalities by deleting + the i'th variable, reducing the system by one variable. */ + newsize = 0; + for (j = 0; j < size; j++) + { + /* If the coefficient for the i'th variable is 0, then we can just + eliminate the variable straightaway. Otherwise, we have to + multiply through by the coefficients we are eliminating. */ + if (A[j][i] == 0) + { + lambda_vector_copy (A[j], A1[newsize], depth); + lambda_vector_copy (B[j], B1[newsize], invariants); + a1[newsize] = a[j]; + newsize++; + } + else if (A[j][i] > 0) + { + for (k = 0; k < size; k++) + { + if (A[k][i] < 0) + { + multiple = lcm (A[j][i], A[k][i]); + f1 = multiple / A[j][i]; + f2 = -1 * multiple / A[k][i]; + + lambda_vector_add_mc (A[j], f1, A[k], f2, + A1[newsize], depth); + lambda_vector_add_mc (B[j], f1, B[k], f2, + B1[newsize], invariants); + a1[newsize] = f1 * a[j] + f2 * a[k]; + newsize++; + } + } + } + } + + swapmatrix = A; + A = A1; + A1 = swapmatrix; + + swapmatrix = B; + B = B1; + B1 = swapmatrix; + + swapvector = a; + a = a1; + a1 = swapvector; + + size = newsize; + } + + return auxillary_nest; +} + +/* Compute the loop bounds for the auxiliary space NEST. + Input system used is Ax <= b. TRANS is the unimodular transformation. + Given the original nest, this function will + 1. Convert the nest into matrix form, which consists of a matrix for the + coefficients, a matrix for the + invariant coefficients, and a vector for the constants. + 2. Use the matrix form to calculate the lattice base for the nest (which is + a dense space) + 3. Compose the dense space transform with the user specified transform, to + get a transform we can easily calculate transformed bounds for. + 4. Multiply the composed transformation matrix times the matrix form of the + loop. + 5. Transform the newly created matrix (from step 4) back into a loop nest + using Fourier-Motzkin elimination to figure out the bounds. */ + +static lambda_loopnest +lambda_compute_auxillary_space (lambda_loopnest nest, + lambda_trans_matrix trans) +{ + lambda_matrix A, B, A1, B1; + lambda_vector a, a1; + lambda_matrix invertedtrans; + int depth, invariants, size; + int i, j; + lambda_loop loop; + lambda_linear_expression expression; + lambda_lattice lattice; + + depth = LN_DEPTH (nest); + invariants = LN_INVARIANTS (nest); + + /* Unfortunately, we can't know the number of constraints we'll have + ahead of time, but this should be enough even in ridiculous loop nest + cases. We must not go over this limit. */ + A = lambda_matrix_new (128, depth); + B = lambda_matrix_new (128, invariants); + a = lambda_vector_new (128); + + A1 = lambda_matrix_new (128, depth); + B1 = lambda_matrix_new (128, invariants); + a1 = lambda_vector_new (128); + + /* Store the bounds in the equation matrix A, constant vector a, and + invariant matrix B, so that we have Ax <= a + B. + This requires a little equation rearranging so that everything is on the + correct side of the inequality. */ + size = 0; + for (i = 0; i < depth; i++) + { + loop = LN_LOOPS (nest)[i]; + + /* First we do the lower bound. */ + if (LL_STEP (loop) > 0) + expression = LL_LOWER_BOUND (loop); + else + expression = LL_UPPER_BOUND (loop); + + for (; expression != NULL; expression = LLE_NEXT (expression)) + { + /* Fill in the coefficient. */ + for (j = 0; j < i; j++) + A[size][j] = LLE_COEFFICIENTS (expression)[j]; + + /* And the invariant coefficient. */ + for (j = 0; j < invariants; j++) + B[size][j] = LLE_INVARIANT_COEFFICIENTS (expression)[j]; + + /* And the constant. */ + a[size] = LLE_CONSTANT (expression); + + /* Convert (2x+3y+2+b)/4 <= z to 2x+3y-4z <= -2-b. IE put all + constants and single variables on */ + A[size][i] = -1 * LLE_DENOMINATOR (expression); + a[size] *= -1; + for (j = 0; j < invariants; j++) + B[size][j] *= -1; + + size++; + /* Need to increase matrix sizes above. */ + gcc_assert (size <= 127); + + } + + /* Then do the exact same thing for the upper bounds. */ + if (LL_STEP (loop) > 0) + expression = LL_UPPER_BOUND (loop); + else + expression = LL_LOWER_BOUND (loop); + + for (; expression != NULL; expression = LLE_NEXT (expression)) + { + /* Fill in the coefficient. */ + for (j = 0; j < i; j++) + A[size][j] = LLE_COEFFICIENTS (expression)[j]; + + /* And the invariant coefficient. */ + for (j = 0; j < invariants; j++) + B[size][j] = LLE_INVARIANT_COEFFICIENTS (expression)[j]; + + /* And the constant. */ + a[size] = LLE_CONSTANT (expression); + + /* Convert z <= (2x+3y+2+b)/4 to -2x-3y+4z <= 2+b. */ + for (j = 0; j < i; j++) + A[size][j] *= -1; + A[size][i] = LLE_DENOMINATOR (expression); + size++; + /* Need to increase matrix sizes above. */ + gcc_assert (size <= 127); + + } + } + + /* Compute the lattice base x = base * y + origin, where y is the + base space. */ + lattice = lambda_lattice_compute_base (nest); + + /* Ax <= a + B then becomes ALy <= a+B - A*origin. L is the lattice base */ + + /* A1 = A * L */ + lambda_matrix_mult (A, LATTICE_BASE (lattice), A1, size, depth, depth); + + /* a1 = a - A * origin constant. */ + lambda_matrix_vector_mult (A, size, depth, LATTICE_ORIGIN (lattice), a1); + lambda_vector_add_mc (a, 1, a1, -1, a1, size); + + /* B1 = B - A * origin invariant. */ + lambda_matrix_mult (A, LATTICE_ORIGIN_INVARIANTS (lattice), B1, size, depth, + invariants); + lambda_matrix_add_mc (B, 1, B1, -1, B1, size, invariants); + + /* Now compute the auxiliary space bounds by first inverting U, multiplying + it by A1, then performing Fourier-Motzkin. */ + + invertedtrans = lambda_matrix_new (depth, depth); + + /* Compute the inverse of U. */ + lambda_matrix_inverse (LTM_MATRIX (trans), + invertedtrans, depth); + + /* A = A1 inv(U). */ + lambda_matrix_mult (A1, invertedtrans, A, size, depth, depth); + + return compute_nest_using_fourier_motzkin (size, depth, invariants, + A, B1, a1); +} + +/* Compute the loop bounds for the target space, using the bounds of + the auxiliary nest AUXILLARY_NEST, and the triangular matrix H. + The target space loop bounds are computed by multiplying the triangular + matrix H by the auxiliary nest, to get the new loop bounds. The sign of + the loop steps (positive or negative) is then used to swap the bounds if + the loop counts downwards. + Return the target loopnest. */ + +static lambda_loopnest +lambda_compute_target_space (lambda_loopnest auxillary_nest, + lambda_trans_matrix H, lambda_vector stepsigns) +{ + lambda_matrix inverse, H1; + int determinant, i, j; + int gcd1, gcd2; + int factor; + + lambda_loopnest target_nest; + int depth, invariants; + lambda_matrix target; + + lambda_loop auxillary_loop, target_loop; + lambda_linear_expression expression, auxillary_expr, target_expr, tmp_expr; + + depth = LN_DEPTH (auxillary_nest); + invariants = LN_INVARIANTS (auxillary_nest); + + inverse = lambda_matrix_new (depth, depth); + determinant = lambda_matrix_inverse (LTM_MATRIX (H), inverse, depth); + + /* H1 is H excluding its diagonal. */ + H1 = lambda_matrix_new (depth, depth); + lambda_matrix_copy (LTM_MATRIX (H), H1, depth, depth); + + for (i = 0; i < depth; i++) + H1[i][i] = 0; + + /* Computes the linear offsets of the loop bounds. */ + target = lambda_matrix_new (depth, depth); + lambda_matrix_mult (H1, inverse, target, depth, depth, depth); + + target_nest = lambda_loopnest_new (depth, invariants); + + for (i = 0; i < depth; i++) + { + + /* Get a new loop structure. */ + target_loop = lambda_loop_new (); + LN_LOOPS (target_nest)[i] = target_loop; + + /* Computes the gcd of the coefficients of the linear part. */ + gcd1 = lambda_vector_gcd (target[i], i); + + /* Include the denominator in the GCD. */ + gcd1 = gcd (gcd1, determinant); + + /* Now divide through by the gcd. */ + for (j = 0; j < i; j++) + target[i][j] = target[i][j] / gcd1; + + expression = lambda_linear_expression_new (depth, invariants); + lambda_vector_copy (target[i], LLE_COEFFICIENTS (expression), depth); + LLE_DENOMINATOR (expression) = determinant / gcd1; + LLE_CONSTANT (expression) = 0; + lambda_vector_clear (LLE_INVARIANT_COEFFICIENTS (expression), + invariants); + LL_LINEAR_OFFSET (target_loop) = expression; + } + + /* For each loop, compute the new bounds from H. */ + for (i = 0; i < depth; i++) + { + auxillary_loop = LN_LOOPS (auxillary_nest)[i]; + target_loop = LN_LOOPS (target_nest)[i]; + LL_STEP (target_loop) = LTM_MATRIX (H)[i][i]; + factor = LTM_MATRIX (H)[i][i]; + + /* First we do the lower bound. */ + auxillary_expr = LL_LOWER_BOUND (auxillary_loop); + + for (; auxillary_expr != NULL; + auxillary_expr = LLE_NEXT (auxillary_expr)) + { + target_expr = lambda_linear_expression_new (depth, invariants); + lambda_vector_matrix_mult (LLE_COEFFICIENTS (auxillary_expr), + depth, inverse, depth, + LLE_COEFFICIENTS (target_expr)); + lambda_vector_mult_const (LLE_COEFFICIENTS (target_expr), + LLE_COEFFICIENTS (target_expr), depth, + factor); + + LLE_CONSTANT (target_expr) = LLE_CONSTANT (auxillary_expr) * factor; + lambda_vector_copy (LLE_INVARIANT_COEFFICIENTS (auxillary_expr), + LLE_INVARIANT_COEFFICIENTS (target_expr), + invariants); + lambda_vector_mult_const (LLE_INVARIANT_COEFFICIENTS (target_expr), + LLE_INVARIANT_COEFFICIENTS (target_expr), + invariants, factor); + LLE_DENOMINATOR (target_expr) = LLE_DENOMINATOR (auxillary_expr); + + if (!lambda_vector_zerop (LLE_COEFFICIENTS (target_expr), depth)) + { + LLE_CONSTANT (target_expr) = LLE_CONSTANT (target_expr) + * determinant; + lambda_vector_mult_const (LLE_INVARIANT_COEFFICIENTS + (target_expr), + LLE_INVARIANT_COEFFICIENTS + (target_expr), invariants, + determinant); + LLE_DENOMINATOR (target_expr) = + LLE_DENOMINATOR (target_expr) * determinant; + } + /* Find the gcd and divide by it here, rather than doing it + at the tree level. */ + gcd1 = lambda_vector_gcd (LLE_COEFFICIENTS (target_expr), depth); + gcd2 = lambda_vector_gcd (LLE_INVARIANT_COEFFICIENTS (target_expr), + invariants); + gcd1 = gcd (gcd1, gcd2); + gcd1 = gcd (gcd1, LLE_CONSTANT (target_expr)); + gcd1 = gcd (gcd1, LLE_DENOMINATOR (target_expr)); + for (j = 0; j < depth; j++) + LLE_COEFFICIENTS (target_expr)[j] /= gcd1; + for (j = 0; j < invariants; j++) + LLE_INVARIANT_COEFFICIENTS (target_expr)[j] /= gcd1; + LLE_CONSTANT (target_expr) /= gcd1; + LLE_DENOMINATOR (target_expr) /= gcd1; + /* Ignore if identical to existing bound. */ + if (!lle_equal (LL_LOWER_BOUND (target_loop), target_expr, depth, + invariants)) + { + LLE_NEXT (target_expr) = LL_LOWER_BOUND (target_loop); + LL_LOWER_BOUND (target_loop) = target_expr; + } + } + /* Now do the upper bound. */ + auxillary_expr = LL_UPPER_BOUND (auxillary_loop); + + for (; auxillary_expr != NULL; + auxillary_expr = LLE_NEXT (auxillary_expr)) + { + target_expr = lambda_linear_expression_new (depth, invariants); + lambda_vector_matrix_mult (LLE_COEFFICIENTS (auxillary_expr), + depth, inverse, depth, + LLE_COEFFICIENTS (target_expr)); + lambda_vector_mult_const (LLE_COEFFICIENTS (target_expr), + LLE_COEFFICIENTS (target_expr), depth, + factor); + LLE_CONSTANT (target_expr) = LLE_CONSTANT (auxillary_expr) * factor; + lambda_vector_copy (LLE_INVARIANT_COEFFICIENTS (auxillary_expr), + LLE_INVARIANT_COEFFICIENTS (target_expr), + invariants); + lambda_vector_mult_const (LLE_INVARIANT_COEFFICIENTS (target_expr), + LLE_INVARIANT_COEFFICIENTS (target_expr), + invariants, factor); + LLE_DENOMINATOR (target_expr) = LLE_DENOMINATOR (auxillary_expr); + + if (!lambda_vector_zerop (LLE_COEFFICIENTS (target_expr), depth)) + { + LLE_CONSTANT (target_expr) = LLE_CONSTANT (target_expr) + * determinant; + lambda_vector_mult_const (LLE_INVARIANT_COEFFICIENTS + (target_expr), + LLE_INVARIANT_COEFFICIENTS + (target_expr), invariants, + determinant); + LLE_DENOMINATOR (target_expr) = + LLE_DENOMINATOR (target_expr) * determinant; + } + /* Find the gcd and divide by it here, instead of at the + tree level. */ + gcd1 = lambda_vector_gcd (LLE_COEFFICIENTS (target_expr), depth); + gcd2 = lambda_vector_gcd (LLE_INVARIANT_COEFFICIENTS (target_expr), + invariants); + gcd1 = gcd (gcd1, gcd2); + gcd1 = gcd (gcd1, LLE_CONSTANT (target_expr)); + gcd1 = gcd (gcd1, LLE_DENOMINATOR (target_expr)); + for (j = 0; j < depth; j++) + LLE_COEFFICIENTS (target_expr)[j] /= gcd1; + for (j = 0; j < invariants; j++) + LLE_INVARIANT_COEFFICIENTS (target_expr)[j] /= gcd1; + LLE_CONSTANT (target_expr) /= gcd1; + LLE_DENOMINATOR (target_expr) /= gcd1; + /* Ignore if equal to existing bound. */ + if (!lle_equal (LL_UPPER_BOUND (target_loop), target_expr, depth, + invariants)) + { + LLE_NEXT (target_expr) = LL_UPPER_BOUND (target_loop); + LL_UPPER_BOUND (target_loop) = target_expr; + } + } + } + for (i = 0; i < depth; i++) + { + target_loop = LN_LOOPS (target_nest)[i]; + /* If necessary, exchange the upper and lower bounds and negate + the step size. */ + if (stepsigns[i] < 0) + { + LL_STEP (target_loop) *= -1; + tmp_expr = LL_LOWER_BOUND (target_loop); + LL_LOWER_BOUND (target_loop) = LL_UPPER_BOUND (target_loop); + LL_UPPER_BOUND (target_loop) = tmp_expr; + } + } + return target_nest; +} + +/* Compute the step signs of TRANS, using TRANS and stepsigns. Return the new + result. */ + +static lambda_vector +lambda_compute_step_signs (lambda_trans_matrix trans, lambda_vector stepsigns) +{ + lambda_matrix matrix, H; + int size; + lambda_vector newsteps; + int i, j, factor, minimum_column; + int temp; + + matrix = LTM_MATRIX (trans); + size = LTM_ROWSIZE (trans); + H = lambda_matrix_new (size, size); + + newsteps = lambda_vector_new (size); + lambda_vector_copy (stepsigns, newsteps, size); + + lambda_matrix_copy (matrix, H, size, size); + + for (j = 0; j < size; j++) + { + lambda_vector row; + row = H[j]; + for (i = j; i < size; i++) + if (row[i] < 0) + lambda_matrix_col_negate (H, size, i); + while (lambda_vector_first_nz (row, size, j + 1) < size) + { + minimum_column = lambda_vector_min_nz (row, size, j); + lambda_matrix_col_exchange (H, size, j, minimum_column); + + temp = newsteps[j]; + newsteps[j] = newsteps[minimum_column]; + newsteps[minimum_column] = temp; + + for (i = j + 1; i < size; i++) + { + factor = row[i] / row[j]; + lambda_matrix_col_add (H, size, j, i, -1 * factor); + } + } + } + return newsteps; +} + +/* Transform NEST according to TRANS, and return the new loopnest. + This involves + 1. Computing a lattice base for the transformation + 2. Composing the dense base with the specified transformation (TRANS) + 3. Decomposing the combined transformation into a lower triangular portion, + and a unimodular portion. + 4. Computing the auxiliary nest using the unimodular portion. + 5. Computing the target nest using the auxiliary nest and the lower + triangular portion. */ + +lambda_loopnest +lambda_loopnest_transform (lambda_loopnest nest, lambda_trans_matrix trans) +{ + lambda_loopnest auxillary_nest, target_nest; + + int depth, invariants; + int i, j; + lambda_lattice lattice; + lambda_trans_matrix trans1, H, U; + lambda_loop loop; + lambda_linear_expression expression; + lambda_vector origin; + lambda_matrix origin_invariants; + lambda_vector stepsigns; + int f; + + depth = LN_DEPTH (nest); + invariants = LN_INVARIANTS (nest); + + /* Keep track of the signs of the loop steps. */ + stepsigns = lambda_vector_new (depth); + for (i = 0; i < depth; i++) + { + if (LL_STEP (LN_LOOPS (nest)[i]) > 0) + stepsigns[i] = 1; + else + stepsigns[i] = -1; + } + + /* Compute the lattice base. */ + lattice = lambda_lattice_compute_base (nest); + trans1 = lambda_trans_matrix_new (depth, depth); + + /* Multiply the transformation matrix by the lattice base. */ + + lambda_matrix_mult (LTM_MATRIX (trans), LATTICE_BASE (lattice), + LTM_MATRIX (trans1), depth, depth, depth); + + /* Compute the Hermite normal form for the new transformation matrix. */ + H = lambda_trans_matrix_new (depth, depth); + U = lambda_trans_matrix_new (depth, depth); + lambda_matrix_hermite (LTM_MATRIX (trans1), depth, LTM_MATRIX (H), + LTM_MATRIX (U)); + + /* Compute the auxiliary loop nest's space from the unimodular + portion. */ + auxillary_nest = lambda_compute_auxillary_space (nest, U); + + /* Compute the loop step signs from the old step signs and the + transformation matrix. */ + stepsigns = lambda_compute_step_signs (trans1, stepsigns); + + /* Compute the target loop nest space from the auxiliary nest and + the lower triangular matrix H. */ + target_nest = lambda_compute_target_space (auxillary_nest, H, stepsigns); + origin = lambda_vector_new (depth); + origin_invariants = lambda_matrix_new (depth, invariants); + lambda_matrix_vector_mult (LTM_MATRIX (trans), depth, depth, + LATTICE_ORIGIN (lattice), origin); + lambda_matrix_mult (LTM_MATRIX (trans), LATTICE_ORIGIN_INVARIANTS (lattice), + origin_invariants, depth, depth, invariants); + + for (i = 0; i < depth; i++) + { + loop = LN_LOOPS (target_nest)[i]; + expression = LL_LINEAR_OFFSET (loop); + if (lambda_vector_zerop (LLE_COEFFICIENTS (expression), depth)) + f = 1; + else + f = LLE_DENOMINATOR (expression); + + LLE_CONSTANT (expression) += f * origin[i]; + + for (j = 0; j < invariants; j++) + LLE_INVARIANT_COEFFICIENTS (expression)[j] += + f * origin_invariants[i][j]; + } + + return target_nest; + +} + +/* Convert a gcc tree expression EXPR to a lambda linear expression, and + return the new expression. DEPTH is the depth of the loopnest. + OUTERINDUCTIONVARS is an array of the induction variables for outer loops + in this nest. INVARIANTS is the array of invariants for the loop. EXTRA + is the amount we have to add/subtract from the expression because of the + type of comparison it is used in. */ + +static lambda_linear_expression +gcc_tree_to_linear_expression (int depth, tree expr, + VEC(tree,heap) *outerinductionvars, + VEC(tree,heap) *invariants, int extra) +{ + lambda_linear_expression lle = NULL; + switch (TREE_CODE (expr)) + { + case INTEGER_CST: + { + lle = lambda_linear_expression_new (depth, 2 * depth); + LLE_CONSTANT (lle) = TREE_INT_CST_LOW (expr); + if (extra != 0) + LLE_CONSTANT (lle) += extra; + + LLE_DENOMINATOR (lle) = 1; + } + break; + case SSA_NAME: + { + tree iv, invar; + size_t i; + for (i = 0; VEC_iterate (tree, outerinductionvars, i, iv); i++) + if (iv != NULL) + { + if (SSA_NAME_VAR (iv) == SSA_NAME_VAR (expr)) + { + lle = lambda_linear_expression_new (depth, 2 * depth); + LLE_COEFFICIENTS (lle)[i] = 1; + if (extra != 0) + LLE_CONSTANT (lle) = extra; + + LLE_DENOMINATOR (lle) = 1; + } + } + for (i = 0; VEC_iterate (tree, invariants, i, invar); i++) + if (invar != NULL) + { + if (SSA_NAME_VAR (invar) == SSA_NAME_VAR (expr)) + { + lle = lambda_linear_expression_new (depth, 2 * depth); + LLE_INVARIANT_COEFFICIENTS (lle)[i] = 1; + if (extra != 0) + LLE_CONSTANT (lle) = extra; + LLE_DENOMINATOR (lle) = 1; + } + } + } + break; + default: + return NULL; + } + + return lle; +} + +/* Return the depth of the loopnest NEST */ + +static int +depth_of_nest (struct loop *nest) +{ + size_t depth = 0; + while (nest) + { + depth++; + nest = nest->inner; + } + return depth; +} + + +/* Return true if OP is invariant in LOOP and all outer loops. */ + +static bool +invariant_in_loop_and_outer_loops (struct loop *loop, tree op) +{ + if (is_gimple_min_invariant (op)) + return true; + if (loop->depth == 0) + return true; + if (!expr_invariant_in_loop_p (loop, op)) + return false; + if (loop->outer + && !invariant_in_loop_and_outer_loops (loop->outer, op)) + return false; + return true; +} + +/* Generate a lambda loop from a gcc loop LOOP. Return the new lambda loop, + or NULL if it could not be converted. + DEPTH is the depth of the loop. + INVARIANTS is a pointer to the array of loop invariants. + The induction variable for this loop should be stored in the parameter + OURINDUCTIONVAR. + OUTERINDUCTIONVARS is an array of induction variables for outer loops. */ + +static lambda_loop +gcc_loop_to_lambda_loop (struct loop *loop, int depth, + VEC(tree,heap) ** invariants, + tree * ourinductionvar, + VEC(tree,heap) * outerinductionvars, + VEC(tree,heap) ** lboundvars, + VEC(tree,heap) ** uboundvars, + VEC(int,heap) ** steps) +{ + tree phi; + tree exit_cond; + tree access_fn, inductionvar; + tree step; + lambda_loop lloop = NULL; + lambda_linear_expression lbound, ubound; + tree test; + int stepint; + int extra = 0; + tree lboundvar, uboundvar, uboundresult; + + /* Find out induction var and exit condition. */ + inductionvar = find_induction_var_from_exit_cond (loop); + exit_cond = get_loop_exit_condition (loop); + + if (inductionvar == NULL || exit_cond == NULL) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot determine exit condition or induction variable for loop.\n"); + return NULL; + } + + test = TREE_OPERAND (exit_cond, 0); + + if (SSA_NAME_DEF_STMT (inductionvar) == NULL_TREE) + { + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot find PHI node for induction variable\n"); + + return NULL; + } + + phi = SSA_NAME_DEF_STMT (inductionvar); + if (TREE_CODE (phi) != PHI_NODE) + { + phi = SINGLE_SSA_TREE_OPERAND (phi, SSA_OP_USE); + if (!phi) + { + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot find PHI node for induction variable\n"); + + return NULL; + } + + phi = SSA_NAME_DEF_STMT (phi); + if (TREE_CODE (phi) != PHI_NODE) + { + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot find PHI node for induction variable\n"); + return NULL; + } + + } + + /* The induction variable name/version we want to put in the array is the + result of the induction variable phi node. */ + *ourinductionvar = PHI_RESULT (phi); + access_fn = instantiate_parameters + (loop, analyze_scalar_evolution (loop, PHI_RESULT (phi))); + if (access_fn == chrec_dont_know) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Access function for induction variable phi is unknown\n"); + + return NULL; + } + + step = evolution_part_in_loop_num (access_fn, loop->num); + if (!step || step == chrec_dont_know) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot determine step of loop.\n"); + + return NULL; + } + if (TREE_CODE (step) != INTEGER_CST) + { + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Step of loop is not integer.\n"); + return NULL; + } + + stepint = TREE_INT_CST_LOW (step); + + /* Only want phis for induction vars, which will have two + arguments. */ + if (PHI_NUM_ARGS (phi) != 2) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: PHI node for induction variable has >2 arguments\n"); + return NULL; + } + + /* Another induction variable check. One argument's source should be + in the loop, one outside the loop. */ + if (flow_bb_inside_loop_p (loop, PHI_ARG_EDGE (phi, 0)->src) + && flow_bb_inside_loop_p (loop, PHI_ARG_EDGE (phi, 1)->src)) + { + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: PHI edges both inside loop, or both outside loop.\n"); + + return NULL; + } + + if (flow_bb_inside_loop_p (loop, PHI_ARG_EDGE (phi, 0)->src)) + { + lboundvar = PHI_ARG_DEF (phi, 1); + lbound = gcc_tree_to_linear_expression (depth, lboundvar, + outerinductionvars, *invariants, + 0); + } + else + { + lboundvar = PHI_ARG_DEF (phi, 0); + lbound = gcc_tree_to_linear_expression (depth, lboundvar, + outerinductionvars, *invariants, + 0); + } + + if (!lbound) + { + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot convert lower bound to linear expression\n"); + + return NULL; + } + /* One part of the test may be a loop invariant tree. */ + VEC_reserve (tree, heap, *invariants, 1); + if (TREE_CODE (TREE_OPERAND (test, 1)) == SSA_NAME + && invariant_in_loop_and_outer_loops (loop, TREE_OPERAND (test, 1))) + VEC_quick_push (tree, *invariants, TREE_OPERAND (test, 1)); + else if (TREE_CODE (TREE_OPERAND (test, 0)) == SSA_NAME + && invariant_in_loop_and_outer_loops (loop, TREE_OPERAND (test, 0))) + VEC_quick_push (tree, *invariants, TREE_OPERAND (test, 0)); + + /* The non-induction variable part of the test is the upper bound variable. + */ + if (TREE_OPERAND (test, 0) == inductionvar) + uboundvar = TREE_OPERAND (test, 1); + else + uboundvar = TREE_OPERAND (test, 0); + + + /* We only size the vectors assuming we have, at max, 2 times as many + invariants as we do loops (one for each bound). + This is just an arbitrary number, but it has to be matched against the + code below. */ + gcc_assert (VEC_length (tree, *invariants) <= (unsigned int) (2 * depth)); + + + /* We might have some leftover. */ + if (TREE_CODE (test) == LT_EXPR) + extra = -1 * stepint; + else if (TREE_CODE (test) == NE_EXPR) + extra = -1 * stepint; + else if (TREE_CODE (test) == GT_EXPR) + extra = -1 * stepint; + else if (TREE_CODE (test) == EQ_EXPR) + extra = 1 * stepint; + + ubound = gcc_tree_to_linear_expression (depth, uboundvar, + outerinductionvars, + *invariants, extra); + uboundresult = build2 (PLUS_EXPR, TREE_TYPE (uboundvar), uboundvar, + build_int_cst (TREE_TYPE (uboundvar), extra)); + VEC_safe_push (tree, heap, *uboundvars, uboundresult); + VEC_safe_push (tree, heap, *lboundvars, lboundvar); + VEC_safe_push (int, heap, *steps, stepint); + if (!ubound) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Unable to convert loop: Cannot convert upper bound to linear expression\n"); + return NULL; + } + + lloop = lambda_loop_new (); + LL_STEP (lloop) = stepint; + LL_LOWER_BOUND (lloop) = lbound; + LL_UPPER_BOUND (lloop) = ubound; + return lloop; +} + +/* Given a LOOP, find the induction variable it is testing against in the exit + condition. Return the induction variable if found, NULL otherwise. */ + +static tree +find_induction_var_from_exit_cond (struct loop *loop) +{ + tree expr = get_loop_exit_condition (loop); + tree ivarop; + tree test; + if (expr == NULL_TREE) + return NULL_TREE; + if (TREE_CODE (expr) != COND_EXPR) + return NULL_TREE; + test = TREE_OPERAND (expr, 0); + if (!COMPARISON_CLASS_P (test)) + return NULL_TREE; + + /* Find the side that is invariant in this loop. The ivar must be the other + side. */ + + if (expr_invariant_in_loop_p (loop, TREE_OPERAND (test, 0))) + ivarop = TREE_OPERAND (test, 1); + else if (expr_invariant_in_loop_p (loop, TREE_OPERAND (test, 1))) + ivarop = TREE_OPERAND (test, 0); + else + return NULL_TREE; + + if (TREE_CODE (ivarop) != SSA_NAME) + return NULL_TREE; + return ivarop; +} + +DEF_VEC_P(lambda_loop); +DEF_VEC_ALLOC_P(lambda_loop,heap); + +/* Generate a lambda loopnest from a gcc loopnest LOOP_NEST. + Return the new loop nest. + INDUCTIONVARS is a pointer to an array of induction variables for the + loopnest that will be filled in during this process. + INVARIANTS is a pointer to an array of invariants that will be filled in + during this process. */ + +lambda_loopnest +gcc_loopnest_to_lambda_loopnest (struct loops *currloops, + struct loop *loop_nest, + VEC(tree,heap) **inductionvars, + VEC(tree,heap) **invariants) +{ + lambda_loopnest ret = NULL; + struct loop *temp = loop_nest; + int depth = depth_of_nest (loop_nest); + size_t i; + VEC(lambda_loop,heap) *loops = NULL; + VEC(tree,heap) *uboundvars = NULL; + VEC(tree,heap) *lboundvars = NULL; + VEC(int,heap) *steps = NULL; + lambda_loop newloop; + tree inductionvar = NULL; + bool perfect_nest = perfect_nest_p (loop_nest); + + if (!perfect_nest && !can_convert_to_perfect_nest (loop_nest)) + goto fail; + + while (temp) + { + newloop = gcc_loop_to_lambda_loop (temp, depth, invariants, + &inductionvar, *inductionvars, + &lboundvars, &uboundvars, + &steps); + if (!newloop) + goto fail; + + VEC_safe_push (tree, heap, *inductionvars, inductionvar); + VEC_safe_push (lambda_loop, heap, loops, newloop); + temp = temp->inner; + } + + if (!perfect_nest) + { + if (!perfect_nestify (currloops, loop_nest, + lboundvars, uboundvars, steps, *inductionvars)) + { + if (dump_file) + fprintf (dump_file, + "Not a perfect loop nest and couldn't convert to one.\n"); + goto fail; + } + else if (dump_file) + fprintf (dump_file, + "Successfully converted loop nest to perfect loop nest.\n"); + } + + ret = lambda_loopnest_new (depth, 2 * depth); + + for (i = 0; VEC_iterate (lambda_loop, loops, i, newloop); i++) + LN_LOOPS (ret)[i] = newloop; + + fail: + VEC_free (lambda_loop, heap, loops); + VEC_free (tree, heap, uboundvars); + VEC_free (tree, heap, lboundvars); + VEC_free (int, heap, steps); + + return ret; +} + +/* Convert a lambda body vector LBV to a gcc tree, and return the new tree. + STMTS_TO_INSERT is a pointer to a tree where the statements we need to be + inserted for us are stored. INDUCTION_VARS is the array of induction + variables for the loop this LBV is from. TYPE is the tree type to use for + the variables and trees involved. */ + +static tree +lbv_to_gcc_expression (lambda_body_vector lbv, + tree type, VEC(tree,heap) *induction_vars, + tree *stmts_to_insert) +{ + tree stmts, stmt, resvar, name; + tree iv; + size_t i; + tree_stmt_iterator tsi; + + /* Create a statement list and a linear expression temporary. */ + stmts = alloc_stmt_list (); + resvar = create_tmp_var (type, "lbvtmp"); + add_referenced_var (resvar); + + /* Start at 0. */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, integer_zero_node); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + + for (i = 0; VEC_iterate (tree, induction_vars, i, iv); i++) + { + if (LBV_COEFFICIENTS (lbv)[i] != 0) + { + tree newname; + tree coeffmult; + + /* newname = coefficient * induction_variable */ + coeffmult = build_int_cst (type, LBV_COEFFICIENTS (lbv)[i]); + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + fold_build2 (MULT_EXPR, type, iv, coeffmult)); + + newname = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = newname; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + + /* name = name + newname */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (PLUS_EXPR, type, name, newname)); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + + } + } + + /* Handle any denominator that occurs. */ + if (LBV_DENOMINATOR (lbv) != 1) + { + tree denominator = build_int_cst (type, LBV_DENOMINATOR (lbv)); + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (CEIL_DIV_EXPR, type, name, denominator)); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + *stmts_to_insert = stmts; + return name; +} + +/* Convert a linear expression from coefficient and constant form to a + gcc tree. + Return the tree that represents the final value of the expression. + LLE is the linear expression to convert. + OFFSET is the linear offset to apply to the expression. + TYPE is the tree type to use for the variables and math. + INDUCTION_VARS is a vector of induction variables for the loops. + INVARIANTS is a vector of the loop nest invariants. + WRAP specifies what tree code to wrap the results in, if there is more than + one (it is either MAX_EXPR, or MIN_EXPR). + STMTS_TO_INSERT Is a pointer to the statement list we fill in with + statements that need to be inserted for the linear expression. */ + +static tree +lle_to_gcc_expression (lambda_linear_expression lle, + lambda_linear_expression offset, + tree type, + VEC(tree,heap) *induction_vars, + VEC(tree,heap) *invariants, + enum tree_code wrap, tree *stmts_to_insert) +{ + tree stmts, stmt, resvar, name; + size_t i; + tree_stmt_iterator tsi; + tree iv, invar; + VEC(tree,heap) *results = NULL; + + gcc_assert (wrap == MAX_EXPR || wrap == MIN_EXPR); + name = NULL_TREE; + /* Create a statement list and a linear expression temporary. */ + stmts = alloc_stmt_list (); + resvar = create_tmp_var (type, "lletmp"); + add_referenced_var (resvar); + + /* Build up the linear expressions, and put the variable representing the + result in the results array. */ + for (; lle != NULL; lle = LLE_NEXT (lle)) + { + /* Start at name = 0. */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, integer_zero_node); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + + /* First do the induction variables. + at the end, name = name + all the induction variables added + together. */ + for (i = 0; VEC_iterate (tree, induction_vars, i, iv); i++) + { + if (LLE_COEFFICIENTS (lle)[i] != 0) + { + tree newname; + tree mult; + tree coeff; + + /* mult = induction variable * coefficient. */ + if (LLE_COEFFICIENTS (lle)[i] == 1) + { + mult = VEC_index (tree, induction_vars, i); + } + else + { + coeff = build_int_cst (type, + LLE_COEFFICIENTS (lle)[i]); + mult = fold_build2 (MULT_EXPR, type, iv, coeff); + } + + /* newname = mult */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, mult); + newname = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = newname; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + + /* name = name + newname */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (PLUS_EXPR, type, name, newname)); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + } + + /* Handle our invariants. + At the end, we have name = name + result of adding all multiplied + invariants. */ + for (i = 0; VEC_iterate (tree, invariants, i, invar); i++) + { + if (LLE_INVARIANT_COEFFICIENTS (lle)[i] != 0) + { + tree newname; + tree mult; + tree coeff; + int invcoeff = LLE_INVARIANT_COEFFICIENTS (lle)[i]; + /* mult = invariant * coefficient */ + if (invcoeff == 1) + { + mult = invar; + } + else + { + coeff = build_int_cst (type, invcoeff); + mult = fold_build2 (MULT_EXPR, type, invar, coeff); + } + + /* newname = mult */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, mult); + newname = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = newname; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + + /* name = name + newname */ + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (PLUS_EXPR, type, name, newname)); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + } + + /* Now handle the constant. + name = name + constant. */ + if (LLE_CONSTANT (lle) != 0) + { + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (PLUS_EXPR, type, name, + build_int_cst (type, LLE_CONSTANT (lle)))); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + + /* Now handle the offset. + name = name + linear offset. */ + if (LLE_CONSTANT (offset) != 0) + { + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (PLUS_EXPR, type, name, + build_int_cst (type, LLE_CONSTANT (offset)))); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + fold_stmt (&stmt); + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + + /* Handle any denominator that occurs. */ + if (LLE_DENOMINATOR (lle) != 1) + { + stmt = build_int_cst (type, LLE_DENOMINATOR (lle)); + stmt = build2 (wrap == MAX_EXPR ? CEIL_DIV_EXPR : FLOOR_DIV_EXPR, + type, name, stmt); + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, stmt); + + /* name = {ceil, floor}(name/denominator) */ + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + VEC_safe_push (tree, heap, results, name); + } + + /* Again, out of laziness, we don't handle this case yet. It's not + hard, it just hasn't occurred. */ + gcc_assert (VEC_length (tree, results) <= 2); + + /* We may need to wrap the results in a MAX_EXPR or MIN_EXPR. */ + if (VEC_length (tree, results) > 1) + { + tree op1 = VEC_index (tree, results, 0); + tree op2 = VEC_index (tree, results, 1); + stmt = build2 (MODIFY_EXPR, void_type_node, resvar, + build2 (wrap, type, op1, op2)); + name = make_ssa_name (resvar, stmt); + TREE_OPERAND (stmt, 0) = name; + tsi = tsi_last (stmts); + tsi_link_after (&tsi, stmt, TSI_CONTINUE_LINKING); + } + + VEC_free (tree, heap, results); + + *stmts_to_insert = stmts; + return name; +} + +/* Transform a lambda loopnest NEW_LOOPNEST, which had TRANSFORM applied to + it, back into gcc code. This changes the + loops, their induction variables, and their bodies, so that they + match the transformed loopnest. + OLD_LOOPNEST is the loopnest before we've replaced it with the new + loopnest. + OLD_IVS is a vector of induction variables from the old loopnest. + INVARIANTS is a vector of loop invariants from the old loopnest. + NEW_LOOPNEST is the new lambda loopnest to replace OLD_LOOPNEST with. + TRANSFORM is the matrix transform that was applied to OLD_LOOPNEST to get + NEW_LOOPNEST. */ + +void +lambda_loopnest_to_gcc_loopnest (struct loop *old_loopnest, + VEC(tree,heap) *old_ivs, + VEC(tree,heap) *invariants, + lambda_loopnest new_loopnest, + lambda_trans_matrix transform) +{ + struct loop *temp; + size_t i = 0; + size_t depth = 0; + VEC(tree,heap) *new_ivs = NULL; + tree oldiv; + + block_stmt_iterator bsi; + + if (dump_file) + { + transform = lambda_trans_matrix_inverse (transform); + fprintf (dump_file, "Inverse of transformation matrix:\n"); + print_lambda_trans_matrix (dump_file, transform); + } + depth = depth_of_nest (old_loopnest); + temp = old_loopnest; + + while (temp) + { + lambda_loop newloop; + basic_block bb; + edge exit; + tree ivvar, ivvarinced, exitcond, stmts; + enum tree_code testtype; + tree newupperbound, newlowerbound; + lambda_linear_expression offset; + tree type; + bool insert_after; + tree inc_stmt; + + oldiv = VEC_index (tree, old_ivs, i); + type = TREE_TYPE (oldiv); + + /* First, build the new induction variable temporary */ + + ivvar = create_tmp_var (type, "lnivtmp"); + add_referenced_var (ivvar); + + VEC_safe_push (tree, heap, new_ivs, ivvar); + + newloop = LN_LOOPS (new_loopnest)[i]; + + /* Linear offset is a bit tricky to handle. Punt on the unhandled + cases for now. */ + offset = LL_LINEAR_OFFSET (newloop); + + gcc_assert (LLE_DENOMINATOR (offset) == 1 && + lambda_vector_zerop (LLE_COEFFICIENTS (offset), depth)); + + /* Now build the new lower bounds, and insert the statements + necessary to generate it on the loop preheader. */ + newlowerbound = lle_to_gcc_expression (LL_LOWER_BOUND (newloop), + LL_LINEAR_OFFSET (newloop), + type, + new_ivs, + invariants, MAX_EXPR, &stmts); + bsi_insert_on_edge (loop_preheader_edge (temp), stmts); + bsi_commit_edge_inserts (); + /* Build the new upper bound and insert its statements in the + basic block of the exit condition */ + newupperbound = lle_to_gcc_expression (LL_UPPER_BOUND (newloop), + LL_LINEAR_OFFSET (newloop), + type, + new_ivs, + invariants, MIN_EXPR, &stmts); + exit = temp->single_exit; + exitcond = get_loop_exit_condition (temp); + bb = bb_for_stmt (exitcond); + bsi = bsi_start (bb); + bsi_insert_after (&bsi, stmts, BSI_NEW_STMT); + + /* Create the new iv. */ + + standard_iv_increment_position (temp, &bsi, &insert_after); + create_iv (newlowerbound, + build_int_cst (type, LL_STEP (newloop)), + ivvar, temp, &bsi, insert_after, &ivvar, + NULL); + + /* Unfortunately, the incremented ivvar that create_iv inserted may not + dominate the block containing the exit condition. + So we simply create our own incremented iv to use in the new exit + test, and let redundancy elimination sort it out. */ + inc_stmt = build2 (PLUS_EXPR, type, + ivvar, build_int_cst (type, LL_STEP (newloop))); + inc_stmt = build2 (MODIFY_EXPR, void_type_node, SSA_NAME_VAR (ivvar), + inc_stmt); + ivvarinced = make_ssa_name (SSA_NAME_VAR (ivvar), inc_stmt); + TREE_OPERAND (inc_stmt, 0) = ivvarinced; + bsi = bsi_for_stmt (exitcond); + bsi_insert_before (&bsi, inc_stmt, BSI_SAME_STMT); + + /* Replace the exit condition with the new upper bound + comparison. */ + + testtype = LL_STEP (newloop) >= 0 ? LE_EXPR : GE_EXPR; + + /* We want to build a conditional where true means exit the loop, and + false means continue the loop. + So swap the testtype if this isn't the way things are.*/ + + if (exit->flags & EDGE_FALSE_VALUE) + testtype = swap_tree_comparison (testtype); + + COND_EXPR_COND (exitcond) = build2 (testtype, + boolean_type_node, + newupperbound, ivvarinced); + update_stmt (exitcond); + VEC_replace (tree, new_ivs, i, ivvar); + + i++; + temp = temp->inner; + } + + /* Rewrite uses of the old ivs so that they are now specified in terms of + the new ivs. */ + + for (i = 0; VEC_iterate (tree, old_ivs, i, oldiv); i++) + { + imm_use_iterator imm_iter; + use_operand_p use_p; + tree oldiv_def; + tree oldiv_stmt = SSA_NAME_DEF_STMT (oldiv); + tree stmt; + + if (TREE_CODE (oldiv_stmt) == PHI_NODE) + oldiv_def = PHI_RESULT (oldiv_stmt); + else + oldiv_def = SINGLE_SSA_TREE_OPERAND (oldiv_stmt, SSA_OP_DEF); + gcc_assert (oldiv_def != NULL_TREE); + + FOR_EACH_IMM_USE_STMT (stmt, imm_iter, oldiv_def) + { + tree newiv, stmts; + lambda_body_vector lbv, newlbv; + + gcc_assert (TREE_CODE (stmt) != PHI_NODE); + + /* Compute the new expression for the induction + variable. */ + depth = VEC_length (tree, new_ivs); + lbv = lambda_body_vector_new (depth); + LBV_COEFFICIENTS (lbv)[i] = 1; + + newlbv = lambda_body_vector_compute_new (transform, lbv); + + newiv = lbv_to_gcc_expression (newlbv, TREE_TYPE (oldiv), + new_ivs, &stmts); + bsi = bsi_for_stmt (stmt); + /* Insert the statements to build that + expression. */ + bsi_insert_before (&bsi, stmts, BSI_SAME_STMT); + + FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter) + propagate_value (use_p, newiv); + update_stmt (stmt); + } + } + VEC_free (tree, heap, new_ivs); +} + +/* Return TRUE if this is not interesting statement from the perspective of + determining if we have a perfect loop nest. */ + +static bool +not_interesting_stmt (tree stmt) +{ + /* Note that COND_EXPR's aren't interesting because if they were exiting the + loop, we would have already failed the number of exits tests. */ + if (TREE_CODE (stmt) == LABEL_EXPR + || TREE_CODE (stmt) == GOTO_EXPR + || TREE_CODE (stmt) == COND_EXPR) + return true; + return false; +} + +/* Return TRUE if PHI uses DEF for it's in-the-loop edge for LOOP. */ + +static bool +phi_loop_edge_uses_def (struct loop *loop, tree phi, tree def) +{ + int i; + for (i = 0; i < PHI_NUM_ARGS (phi); i++) + if (flow_bb_inside_loop_p (loop, PHI_ARG_EDGE (phi, i)->src)) + if (PHI_ARG_DEF (phi, i) == def) + return true; + return false; +} + +/* Return TRUE if STMT is a use of PHI_RESULT. */ + +static bool +stmt_uses_phi_result (tree stmt, tree phi_result) +{ + tree use = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_USE); + + /* This is conservatively true, because we only want SIMPLE bumpers + of the form x +- constant for our pass. */ + return (use == phi_result); +} + +/* STMT is a bumper stmt for LOOP if the version it defines is used in the + in-loop-edge in a phi node, and the operand it uses is the result of that + phi node. + I.E. i_29 = i_3 + 1 + i_3 = PHI (0, i_29); */ + +static bool +stmt_is_bumper_for_loop (struct loop *loop, tree stmt) +{ + tree use; + tree def; + imm_use_iterator iter; + use_operand_p use_p; + + def = SINGLE_SSA_TREE_OPERAND (stmt, SSA_OP_DEF); + if (!def) + return false; + + FOR_EACH_IMM_USE_FAST (use_p, iter, def) + { + use = USE_STMT (use_p); + if (TREE_CODE (use) == PHI_NODE) + { + if (phi_loop_edge_uses_def (loop, use, def)) + if (stmt_uses_phi_result (stmt, PHI_RESULT (use))) + return true; + } + } + return false; +} + + +/* Return true if LOOP is a perfect loop nest. + Perfect loop nests are those loop nests where all code occurs in the + innermost loop body. + If S is a program statement, then + + i.e. + DO I = 1, 20 + S1 + DO J = 1, 20 + ... + END DO + END DO + is not a perfect loop nest because of S1. + + DO I = 1, 20 + DO J = 1, 20 + S1 + ... + END DO + END DO + is a perfect loop nest. + + Since we don't have high level loops anymore, we basically have to walk our + statements and ignore those that are there because the loop needs them (IE + the induction variable increment, and jump back to the top of the loop). */ + +bool +perfect_nest_p (struct loop *loop) +{ + basic_block *bbs; + size_t i; + tree exit_cond; + + if (!loop->inner) + return true; + bbs = get_loop_body (loop); + exit_cond = get_loop_exit_condition (loop); + for (i = 0; i < loop->num_nodes; i++) + { + if (bbs[i]->loop_father == loop) + { + block_stmt_iterator bsi; + for (bsi = bsi_start (bbs[i]); !bsi_end_p (bsi); bsi_next (&bsi)) + { + tree stmt = bsi_stmt (bsi); + if (stmt == exit_cond + || not_interesting_stmt (stmt) + || stmt_is_bumper_for_loop (loop, stmt)) + continue; + free (bbs); + return false; + } + } + } + free (bbs); + /* See if the inner loops are perfectly nested as well. */ + if (loop->inner) + return perfect_nest_p (loop->inner); + return true; +} + +/* Replace the USES of X in STMT, or uses with the same step as X with Y. + YINIT is the initial value of Y, REPLACEMENTS is a hash table to + avoid creating duplicate temporaries and FIRSTBSI is statement + iterator where new temporaries should be inserted at the beginning + of body basic block. */ + +static void +replace_uses_equiv_to_x_with_y (struct loop *loop, tree stmt, tree x, + int xstep, tree y, tree yinit, + htab_t replacements, + block_stmt_iterator *firstbsi) +{ + ssa_op_iter iter; + use_operand_p use_p; + + FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE) + { + tree use = USE_FROM_PTR (use_p); + tree step = NULL_TREE; + tree scev, init, val, var, setstmt; + struct tree_map *h, in; + void **loc; + + /* Replace uses of X with Y right away. */ + if (use == x) + { + SET_USE (use_p, y); + continue; + } + + scev = instantiate_parameters (loop, + analyze_scalar_evolution (loop, use)); + + if (scev == NULL || scev == chrec_dont_know) + continue; + + step = evolution_part_in_loop_num (scev, loop->num); + if (step == NULL + || step == chrec_dont_know + || TREE_CODE (step) != INTEGER_CST + || int_cst_value (step) != xstep) + continue; + + /* Use REPLACEMENTS hash table to cache already created + temporaries. */ + in.hash = htab_hash_pointer (use); + in.from = use; + h = htab_find_with_hash (replacements, &in, in.hash); + if (h != NULL) + { + SET_USE (use_p, h->to); + continue; + } + + /* USE which has the same step as X should be replaced + with a temporary set to Y + YINIT - INIT. */ + init = initial_condition_in_loop_num (scev, loop->num); + gcc_assert (init != NULL && init != chrec_dont_know); + if (TREE_TYPE (use) == TREE_TYPE (y)) + { + val = fold_build2 (MINUS_EXPR, TREE_TYPE (y), init, yinit); + val = fold_build2 (PLUS_EXPR, TREE_TYPE (y), y, val); + if (val == y) + { + /* If X has the same type as USE, the same step + and same initial value, it can be replaced by Y. */ + SET_USE (use_p, y); + continue; + } + } + else + { + val = fold_build2 (MINUS_EXPR, TREE_TYPE (y), y, yinit); + val = fold_convert (TREE_TYPE (use), val); + val = fold_build2 (PLUS_EXPR, TREE_TYPE (use), val, init); + } + + /* Create a temporary variable and insert it at the beginning + of the loop body basic block, right after the PHI node + which sets Y. */ + var = create_tmp_var (TREE_TYPE (use), "perfecttmp"); + add_referenced_var (var); + val = force_gimple_operand_bsi (firstbsi, val, false, NULL); + setstmt = build2 (MODIFY_EXPR, void_type_node, var, val); + var = make_ssa_name (var, setstmt); + TREE_OPERAND (setstmt, 0) = var; + bsi_insert_before (firstbsi, setstmt, BSI_SAME_STMT); + update_stmt (setstmt); + SET_USE (use_p, var); + h = ggc_alloc (sizeof (struct tree_map)); + h->hash = in.hash; + h->from = use; + h->to = var; + loc = htab_find_slot_with_hash (replacements, h, in.hash, INSERT); + gcc_assert ((*(struct tree_map **)loc) == NULL); + *(struct tree_map **) loc = h; + } +} + +/* Return true if STMT is an exit PHI for LOOP */ + +static bool +exit_phi_for_loop_p (struct loop *loop, tree stmt) +{ + + if (TREE_CODE (stmt) != PHI_NODE + || PHI_NUM_ARGS (stmt) != 1 + || bb_for_stmt (stmt) != loop->single_exit->dest) + return false; + + return true; +} + +/* Return true if STMT can be put back into the loop INNER, by + copying it to the beginning of that loop and changing the uses. */ + +static bool +can_put_in_inner_loop (struct loop *inner, tree stmt) +{ + imm_use_iterator imm_iter; + use_operand_p use_p; + + gcc_assert (TREE_CODE (stmt) == MODIFY_EXPR); + if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS) + || !expr_invariant_in_loop_p (inner, TREE_OPERAND (stmt, 1))) + return false; + + FOR_EACH_IMM_USE_FAST (use_p, imm_iter, TREE_OPERAND (stmt, 0)) + { + if (!exit_phi_for_loop_p (inner, USE_STMT (use_p))) + { + basic_block immbb = bb_for_stmt (USE_STMT (use_p)); + + if (!flow_bb_inside_loop_p (inner, immbb)) + return false; + } + } + return true; +} + +/* Return true if STMT can be put *after* the inner loop of LOOP. */ +static bool +can_put_after_inner_loop (struct loop *loop, tree stmt) +{ + imm_use_iterator imm_iter; + use_operand_p use_p; + + if (!ZERO_SSA_OPERANDS (stmt, SSA_OP_ALL_VIRTUALS)) + return false; + + FOR_EACH_IMM_USE_FAST (use_p, imm_iter, TREE_OPERAND (stmt, 0)) + { + if (!exit_phi_for_loop_p (loop, USE_STMT (use_p))) + { + basic_block immbb = bb_for_stmt (USE_STMT (use_p)); + + if (!dominated_by_p (CDI_DOMINATORS, + immbb, + loop->inner->header) + && !can_put_in_inner_loop (loop->inner, stmt)) + return false; + } + } + return true; +} + + + +/* Return TRUE if LOOP is an imperfect nest that we can convert to a + perfect one. At the moment, we only handle imperfect nests of + depth 2, where all of the statements occur after the inner loop. */ + +static bool +can_convert_to_perfect_nest (struct loop *loop) +{ + basic_block *bbs; + tree exit_condition, phi; + size_t i; + block_stmt_iterator bsi; + basic_block exitdest; + + /* Can't handle triply nested+ loops yet. */ + if (!loop->inner || loop->inner->inner) + return false; + + bbs = get_loop_body (loop); + exit_condition = get_loop_exit_condition (loop); + for (i = 0; i < loop->num_nodes; i++) + { + if (bbs[i]->loop_father == loop) + { + for (bsi = bsi_start (bbs[i]); !bsi_end_p (bsi); bsi_next (&bsi)) + { + tree stmt = bsi_stmt (bsi); + + if (stmt == exit_condition + || not_interesting_stmt (stmt) + || stmt_is_bumper_for_loop (loop, stmt)) + continue; + + /* If this is a scalar operation that can be put back + into the inner loop, or after the inner loop, through + copying, then do so. This works on the theory that + any amount of scalar code we have to reduplicate + into or after the loops is less expensive that the + win we get from rearranging the memory walk + the loop is doing so that it has better + cache behavior. */ + if (TREE_CODE (stmt) == MODIFY_EXPR) + { + use_operand_p use_a, use_b; + imm_use_iterator imm_iter; + ssa_op_iter op_iter, op_iter1; + tree op0 = TREE_OPERAND (stmt, 0); + tree scev = instantiate_parameters + (loop, analyze_scalar_evolution (loop, op0)); + + /* If the IV is simple, it can be duplicated. */ + if (!automatically_generated_chrec_p (scev)) + { + tree step = evolution_part_in_loop_num (scev, loop->num); + if (step && step != chrec_dont_know + && TREE_CODE (step) == INTEGER_CST) + continue; + } + + /* The statement should not define a variable used + in the inner loop. */ + if (TREE_CODE (op0) == SSA_NAME) + FOR_EACH_IMM_USE_FAST (use_a, imm_iter, op0) + if (bb_for_stmt (USE_STMT (use_a))->loop_father + == loop->inner) + goto fail; + + FOR_EACH_SSA_USE_OPERAND (use_a, stmt, op_iter, SSA_OP_USE) + { + tree node, op = USE_FROM_PTR (use_a); + + /* The variables should not be used in both loops. */ + FOR_EACH_IMM_USE_FAST (use_b, imm_iter, op) + if (bb_for_stmt (USE_STMT (use_b))->loop_father + == loop->inner) + goto fail; + + /* The statement should not use the value of a + scalar that was modified in the loop. */ + node = SSA_NAME_DEF_STMT (op); + if (TREE_CODE (node) == PHI_NODE) + FOR_EACH_PHI_ARG (use_b, node, op_iter1, SSA_OP_USE) + { + tree arg = USE_FROM_PTR (use_b); + + if (TREE_CODE (arg) == SSA_NAME) + { + tree arg_stmt = SSA_NAME_DEF_STMT (arg); + + if (bb_for_stmt (arg_stmt)->loop_father + == loop->inner) + goto fail; + } + } + } + + if (can_put_in_inner_loop (loop->inner, stmt) + || can_put_after_inner_loop (loop, stmt)) + continue; + } + + /* Otherwise, if the bb of a statement we care about isn't + dominated by the header of the inner loop, then we can't + handle this case right now. This test ensures that the + statement comes completely *after* the inner loop. */ + if (!dominated_by_p (CDI_DOMINATORS, + bb_for_stmt (stmt), + loop->inner->header)) + goto fail; + } + } + } + + /* We also need to make sure the loop exit only has simple copy phis in it, + otherwise we don't know how to transform it into a perfect nest right + now. */ + exitdest = loop->single_exit->dest; + + for (phi = phi_nodes (exitdest); phi; phi = PHI_CHAIN (phi)) + if (PHI_NUM_ARGS (phi) != 1) + goto fail; + + free (bbs); + return true; + + fail: + free (bbs); + return false; +} + +/* Transform the loop nest into a perfect nest, if possible. + LOOPS is the current struct loops * + LOOP is the loop nest to transform into a perfect nest + LBOUNDS are the lower bounds for the loops to transform + UBOUNDS are the upper bounds for the loops to transform + STEPS is the STEPS for the loops to transform. + LOOPIVS is the induction variables for the loops to transform. + + Basically, for the case of + + FOR (i = 0; i < 50; i++) + { + FOR (j =0; j < 50; j++) + { + <whatever> + } + <some code> + } + + This function will transform it into a perfect loop nest by splitting the + outer loop into two loops, like so: + + FOR (i = 0; i < 50; i++) + { + FOR (j = 0; j < 50; j++) + { + <whatever> + } + } + + FOR (i = 0; i < 50; i ++) + { + <some code> + } + + Return FALSE if we can't make this loop into a perfect nest. */ + +static bool +perfect_nestify (struct loops *loops, + struct loop *loop, + VEC(tree,heap) *lbounds, + VEC(tree,heap) *ubounds, + VEC(int,heap) *steps, + VEC(tree,heap) *loopivs) +{ + basic_block *bbs; + tree exit_condition; + tree then_label, else_label, cond_stmt; + basic_block preheaderbb, headerbb, bodybb, latchbb, olddest; + int i; + block_stmt_iterator bsi, firstbsi; + bool insert_after; + edge e; + struct loop *newloop; + tree phi; + tree uboundvar; + tree stmt; + tree oldivvar, ivvar, ivvarinced; + VEC(tree,heap) *phis = NULL; + htab_t replacements = NULL; + + /* Create the new loop. */ + olddest = loop->single_exit->dest; + preheaderbb = loop_split_edge_with (loop->single_exit, NULL); + headerbb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb); + + /* Push the exit phi nodes that we are moving. */ + for (phi = phi_nodes (olddest); phi; phi = PHI_CHAIN (phi)) + { + VEC_reserve (tree, heap, phis, 2); + VEC_quick_push (tree, phis, PHI_RESULT (phi)); + VEC_quick_push (tree, phis, PHI_ARG_DEF (phi, 0)); + } + e = redirect_edge_and_branch (single_succ_edge (preheaderbb), headerbb); + + /* Remove the exit phis from the old basic block. Make sure to set + PHI_RESULT to null so it doesn't get released. */ + while (phi_nodes (olddest) != NULL) + { + SET_PHI_RESULT (phi_nodes (olddest), NULL); + remove_phi_node (phi_nodes (olddest), NULL); + } + + /* and add them back to the new basic block. */ + while (VEC_length (tree, phis) != 0) + { + tree def; + tree phiname; + def = VEC_pop (tree, phis); + phiname = VEC_pop (tree, phis); + phi = create_phi_node (phiname, preheaderbb); + add_phi_arg (phi, def, single_pred_edge (preheaderbb)); + } + flush_pending_stmts (e); + VEC_free (tree, heap, phis); + + bodybb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb); + latchbb = create_empty_bb (EXIT_BLOCK_PTR->prev_bb); + make_edge (headerbb, bodybb, EDGE_FALLTHRU); + then_label = build1 (GOTO_EXPR, void_type_node, tree_block_label (latchbb)); + else_label = build1 (GOTO_EXPR, void_type_node, tree_block_label (olddest)); + cond_stmt = build3 (COND_EXPR, void_type_node, + build2 (NE_EXPR, boolean_type_node, + integer_one_node, + integer_zero_node), + then_label, else_label); + bsi = bsi_start (bodybb); + bsi_insert_after (&bsi, cond_stmt, BSI_NEW_STMT); + e = make_edge (bodybb, olddest, EDGE_FALSE_VALUE); + make_edge (bodybb, latchbb, EDGE_TRUE_VALUE); + make_edge (latchbb, headerbb, EDGE_FALLTHRU); + + /* Update the loop structures. */ + newloop = duplicate_loop (loops, loop, olddest->loop_father); + newloop->header = headerbb; + newloop->latch = latchbb; + newloop->single_exit = e; + add_bb_to_loop (latchbb, newloop); + add_bb_to_loop (bodybb, newloop); + add_bb_to_loop (headerbb, newloop); + set_immediate_dominator (CDI_DOMINATORS, bodybb, headerbb); + set_immediate_dominator (CDI_DOMINATORS, headerbb, preheaderbb); + set_immediate_dominator (CDI_DOMINATORS, preheaderbb, + loop->single_exit->src); + set_immediate_dominator (CDI_DOMINATORS, latchbb, bodybb); + set_immediate_dominator (CDI_DOMINATORS, olddest, bodybb); + /* Create the new iv. */ + oldivvar = VEC_index (tree, loopivs, 0); + ivvar = create_tmp_var (TREE_TYPE (oldivvar), "perfectiv"); + add_referenced_var (ivvar); + standard_iv_increment_position (newloop, &bsi, &insert_after); + create_iv (VEC_index (tree, lbounds, 0), + build_int_cst (TREE_TYPE (oldivvar), VEC_index (int, steps, 0)), + ivvar, newloop, &bsi, insert_after, &ivvar, &ivvarinced); + + /* Create the new upper bound. This may be not just a variable, so we copy + it to one just in case. */ + + exit_condition = get_loop_exit_condition (newloop); + uboundvar = create_tmp_var (integer_type_node, "uboundvar"); + add_referenced_var (uboundvar); + stmt = build2 (MODIFY_EXPR, void_type_node, uboundvar, + VEC_index (tree, ubounds, 0)); + uboundvar = make_ssa_name (uboundvar, stmt); + TREE_OPERAND (stmt, 0) = uboundvar; + + if (insert_after) + bsi_insert_after (&bsi, stmt, BSI_SAME_STMT); + else + bsi_insert_before (&bsi, stmt, BSI_SAME_STMT); + update_stmt (stmt); + COND_EXPR_COND (exit_condition) = build2 (GE_EXPR, + boolean_type_node, + uboundvar, + ivvarinced); + update_stmt (exit_condition); + replacements = htab_create_ggc (20, tree_map_hash, + tree_map_eq, NULL); + bbs = get_loop_body_in_dom_order (loop); + /* Now move the statements, and replace the induction variable in the moved + statements with the correct loop induction variable. */ + oldivvar = VEC_index (tree, loopivs, 0); + firstbsi = bsi_start (bodybb); + for (i = loop->num_nodes - 1; i >= 0 ; i--) + { + block_stmt_iterator tobsi = bsi_last (bodybb); + if (bbs[i]->loop_father == loop) + { + /* If this is true, we are *before* the inner loop. + If this isn't true, we are *after* it. + + The only time can_convert_to_perfect_nest returns true when we + have statements before the inner loop is if they can be moved + into the inner loop. + + The only time can_convert_to_perfect_nest returns true when we + have statements after the inner loop is if they can be moved into + the new split loop. */ + + if (dominated_by_p (CDI_DOMINATORS, loop->inner->header, bbs[i])) + { + block_stmt_iterator header_bsi + = bsi_after_labels (loop->inner->header); + + for (bsi = bsi_start (bbs[i]); !bsi_end_p (bsi);) + { + tree stmt = bsi_stmt (bsi); + + if (stmt == exit_condition + || not_interesting_stmt (stmt) + || stmt_is_bumper_for_loop (loop, stmt)) + { + bsi_next (&bsi); + continue; + } + + bsi_move_before (&bsi, &header_bsi); + } + } + else + { + /* Note that the bsi only needs to be explicitly incremented + when we don't move something, since it is automatically + incremented when we do. */ + for (bsi = bsi_start (bbs[i]); !bsi_end_p (bsi);) + { + ssa_op_iter i; + tree n, stmt = bsi_stmt (bsi); + + if (stmt == exit_condition + || not_interesting_stmt (stmt) + || stmt_is_bumper_for_loop (loop, stmt)) + { + bsi_next (&bsi); + continue; + } + + replace_uses_equiv_to_x_with_y + (loop, stmt, oldivvar, VEC_index (int, steps, 0), ivvar, + VEC_index (tree, lbounds, 0), replacements, &firstbsi); + + bsi_move_before (&bsi, &tobsi); + + /* If the statement has any virtual operands, they may + need to be rewired because the original loop may + still reference them. */ + FOR_EACH_SSA_TREE_OPERAND (n, stmt, i, SSA_OP_ALL_VIRTUALS) + mark_sym_for_renaming (SSA_NAME_VAR (n)); + } + } + + } + } + + free (bbs); + htab_delete (replacements); + return perfect_nest_p (loop); +} + +/* Return true if TRANS is a legal transformation matrix that respects + the dependence vectors in DISTS and DIRS. The conservative answer + is false. + + "Wolfe proves that a unimodular transformation represented by the + matrix T is legal when applied to a loop nest with a set of + lexicographically non-negative distance vectors RDG if and only if + for each vector d in RDG, (T.d >= 0) is lexicographically positive. + i.e.: if and only if it transforms the lexicographically positive + distance vectors to lexicographically positive vectors. Note that + a unimodular matrix must transform the zero vector (and only it) to + the zero vector." S.Muchnick. */ + +bool +lambda_transform_legal_p (lambda_trans_matrix trans, + int nb_loops, + VEC (ddr_p, heap) *dependence_relations) +{ + unsigned int i, j; + lambda_vector distres; + struct data_dependence_relation *ddr; + + gcc_assert (LTM_COLSIZE (trans) == nb_loops + && LTM_ROWSIZE (trans) == nb_loops); + + /* When there is an unknown relation in the dependence_relations, we + know that it is no worth looking at this loop nest: give up. */ + ddr = VEC_index (ddr_p, dependence_relations, 0); + if (ddr == NULL) + return true; + if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) + return false; + + distres = lambda_vector_new (nb_loops); + + /* For each distance vector in the dependence graph. */ + for (i = 0; VEC_iterate (ddr_p, dependence_relations, i, ddr); i++) + { + /* Don't care about relations for which we know that there is no + dependence, nor about read-read (aka. output-dependences): + these data accesses can happen in any order. */ + if (DDR_ARE_DEPENDENT (ddr) == chrec_known + || (DR_IS_READ (DDR_A (ddr)) && DR_IS_READ (DDR_B (ddr)))) + continue; + + /* Conservatively answer: "this transformation is not valid". */ + if (DDR_ARE_DEPENDENT (ddr) == chrec_dont_know) + return false; + + /* If the dependence could not be captured by a distance vector, + conservatively answer that the transform is not valid. */ + if (DDR_NUM_DIST_VECTS (ddr) == 0) + return false; + + /* Compute trans.dist_vect */ + for (j = 0; j < DDR_NUM_DIST_VECTS (ddr); j++) + { + lambda_matrix_vector_mult (LTM_MATRIX (trans), nb_loops, nb_loops, + DDR_DIST_VECT (ddr, j), distres); + + if (!lambda_vector_lexico_pos (distres, nb_loops)) + return false; + } + } + return true; +} |