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authorRong Xu <xur@google.com>2014-07-21 23:47:22 (GMT)
committerRong Xu <xur@google.com>2014-07-29 22:31:03 (GMT)
commit38a8aecfb882072900434499696b5c32a2274515 (patch)
tree2aac97f0ae24b03cd98c1a06e989c031c173f889 /gcc-4.9/gcc/cfgloop.c
parentc231900e5dcc14d8296bd9f62b45997a49d4d5e7 (diff)
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[4.9] Switch gcc-4.9 to use google/gcc-4_9 branch.
This source drop uses svn version r212828 of google/gcc-4.9 branch. We also cherry-picked r213062, r213063 and r213064 to fix windows build issues. All gcc-4.9 patches before July 3rd are ported to google/gcc-4.9. The following prior commits has not been merged to google branch yet. (They are included in this commit). e7af147f979e657fe2df00808e5b4319b0e088c6, baf87df3cb2683649ba7e9872362a7e721117c23, and c231900e5dcc14d8296bd9f62b45997a49d4d5e7. Change-Id: I4bea3ea470387ff751c2be4cb0d4a12059b9299b
Diffstat (limited to 'gcc-4.9/gcc/cfgloop.c')
-rw-r--r--gcc-4.9/gcc/cfgloop.c94
1 files changed, 84 insertions, 10 deletions
diff --git a/gcc-4.9/gcc/cfgloop.c b/gcc-4.9/gcc/cfgloop.c
index 70744d8..14693f1 100644
--- a/gcc-4.9/gcc/cfgloop.c
+++ b/gcc-4.9/gcc/cfgloop.c
@@ -1168,24 +1168,98 @@ get_loop_exit_edges (const struct loop *loop)
return edges;
}
-/* Counts the number of conditional branches inside LOOP. */
+/* Determine if INSN is a floating point set. */
-unsigned
-num_loop_branches (const struct loop *loop)
+static bool
+insn_has_fp_set(rtx insn)
{
- unsigned i, n;
- basic_block * body;
+ int i;
+ rtx pat = PATTERN(insn);
+ if (GET_CODE (pat) == SET)
+ return (FLOAT_MODE_P (GET_MODE (SET_DEST (pat))));
+ else if (GET_CODE (pat) == PARALLEL)
+ {
+ for (i = 0; i < XVECLEN (pat, 0); i++)
+ {
+ rtx sub = XVECEXP (pat, 0, i);
+ if (GET_CODE (sub) == SET)
+ return (FLOAT_MODE_P (GET_MODE (SET_DEST (sub))));
+ }
+ }
+ return false;
+}
- gcc_assert (loop->latch != EXIT_BLOCK_PTR_FOR_FN (cfun));
+/* Analyzes the instructions inside LOOP, updating the DESC. Currently counts
+ the number of conditional branch instructions, calls and fp instructions,
+ as well as the average number of branches executed per iteration. */
+
+void
+analyze_loop_insns (const struct loop *loop, struct niter_desc *desc)
+{
+ unsigned i, nbranch;
+ gcov_type weighted_nbranch;
+ bool has_call, has_fp;
+ basic_block * body, bb;
+ rtx insn;
+ gcov_type header_count = loop->header->count;
+
+ nbranch = weighted_nbranch = 0;
+ has_call = has_fp = false;
body = get_loop_body (loop);
- n = 0;
for (i = 0; i < loop->num_nodes; i++)
- if (EDGE_COUNT (body[i]->succs) >= 2)
- n++;
+ {
+ bb = body[i];
+
+ if (EDGE_COUNT (bb->succs) >= 2)
+ {
+ nbranch++;
+
+ /* If this block is executed less frequently than the header (loop
+ entry), then it is weighted based on its execution count, which
+ will be turned into a ratio compared to the loop header below. */
+ if (bb->count < header_count)
+ weighted_nbranch += bb->count;
+
+ /* When it is executed more frequently than the header (i.e. it is
+ in a nested inner loop), simply weight the branch the same as the
+ header execution count, so that it will contribute 1 branch to
+ the ratio computed below. */
+ else
+ weighted_nbranch += header_count;
+ }
+
+ /* No need to iterate through the instructions below if
+ both flags have already been set. */
+ if (has_call && has_fp)
+ continue;
+
+ FOR_BB_INSNS (bb, insn)
+ {
+ if (!INSN_P (insn))
+ continue;
+
+ if (!has_call)
+ has_call = CALL_P (insn);
+
+ if (!has_fp)
+ has_fp = insn_has_fp_set (insn);
+ }
+ }
free (body);
- return n;
+ desc->num_branches = nbranch;
+ /* Now divide the weights computed above by the loop header execution count,
+ to compute the average number of branches through the loop. By adding
+ header_count/2 to the numerator we round to nearest with integer
+ division. */
+ if (header_count != 0)
+ desc->av_num_branches
+ = (weighted_nbranch + header_count/2) / header_count;
+ else
+ desc->av_num_branches = 0;
+ desc->has_call = has_call;
+ desc->has_fp = has_fp;
}
/* Adds basic block BB to LOOP. */