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authorSebastian Pop <s.pop@samsung.com>2015-08-28 20:36:58 (GMT)
committerSebastian Pop <s.pop@samsung.com>2015-08-28 21:47:04 (GMT)
commitfa0139c9969e54f37f0add025af87cc21b46ffcb (patch)
tree22bc0625401e4f1eb473c944b11bc9dadc48d2c2
parentc39d2a2bd89ed7a9ff995f2fc1e2e693fab8ee9f (diff)
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backport patch to fix PR65048
PR tree-optimization/65048 * tree-ssa-threadupdate.c (valid_jump_thread_path): New. (thread_through_all_blocks): Call valid_jump_thread_path. Remove invalid FSM jump-thread paths. PR tree-optimization/65048 * gcc.dg/tree-ssa/ssa-dom-thread-9.c: New.
-rw-r--r--gcc-4.9/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-9.c50
-rw-r--r--gcc-4.9/gcc/tree-ssa-threadupdate.c40
2 files changed, 84 insertions, 6 deletions
diff --git a/gcc-4.9/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-9.c b/gcc-4.9/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-9.c
new file mode 100644
index 0000000..6be4203
--- /dev/null
+++ b/gcc-4.9/gcc/testsuite/gcc.dg/tree-ssa/ssa-dom-thread-9.c
@@ -0,0 +1,50 @@
+/* PR 65048 */
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+int a, b, c, d;
+void fn (void);
+
+int
+foo (x)
+{
+ switch (x)
+ {
+ case 'A':
+ return 'T';
+ case 'U':
+ return 'A';
+ }
+}
+
+void
+bar (int x, int y)
+{
+ switch (c)
+ {
+ case 'U':
+ switch (x)
+ {
+ default:
+ fn ();
+ case 'G':
+ switch (y)
+ {
+ case 'A':
+ d = 7;
+ }
+ }
+ }
+}
+
+void
+baz (void)
+{
+ while (1)
+ {
+ a = foo ();
+ b = foo ();
+ bar (a, b);
+ }
+}
+
diff --git a/gcc-4.9/gcc/tree-ssa-threadupdate.c b/gcc-4.9/gcc/tree-ssa-threadupdate.c
index d1b289f..3c7df9a 100644
--- a/gcc-4.9/gcc/tree-ssa-threadupdate.c
+++ b/gcc-4.9/gcc/tree-ssa-threadupdate.c
@@ -1772,6 +1772,21 @@ duplicate_seme_region (edge entry, edge exit,
return true;
}
+/* Return true when PATH is a valid jump-thread path. */
+
+static bool
+valid_jump_thread_path (vec<jump_thread_edge *> *path)
+{
+ unsigned len = path->length ();
+
+ /* Check that the path is connected. */
+ for (unsigned int j = 0; j < len - 1; j++)
+ if ((*path)[j]->e->dest != (*path)[j+1]->e->src)
+ return false;
+
+ return true;
+}
+
/* Walk through all blocks and thread incoming edges to the appropriate
outgoing edge for each edge pair recorded in THREADED_EDGES.
@@ -1807,12 +1822,25 @@ thread_through_all_blocks (bool may_peel_loop_headers)
vec<jump_thread_edge *> *path = paths[i];
edge entry = (*path)[0]->e;
- if ((*path)[0]->type != EDGE_FSM_THREAD
- /* Do not jump-thread twice from the same block. */
- || bitmap_bit_p (threaded_blocks, entry->src->index)) {
- i++;
- continue;
- }
+ /* Only code-generate FSM jump-threads in this loop. */
+ if ((*path)[0]->type != EDGE_FSM_THREAD)
+ {
+ i++;
+ continue;
+ }
+
+ /* Do not jump-thread twice from the same block. */
+ if (bitmap_bit_p (threaded_blocks, entry->src->index)
+ /* Verify that the jump thread path is still valid: a
+ previous jump-thread may have changed the CFG, and
+ invalidated the current path. */
+ || !valid_jump_thread_path (path))
+ {
+ /* Remove invalid FSM jump-thread paths. */
+ delete_jump_thread_path (path);
+ paths.unordered_remove (i);
+ continue;
+ }
unsigned len = path->length ();
edge exit = (*path)[len - 1]->e;