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-rw-r--r--gcc-4.9/gcc/tree-ssa-loop-niter.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/gcc-4.9/gcc/tree-ssa-loop-niter.c b/gcc-4.9/gcc/tree-ssa-loop-niter.c
index cb9214fbb..db069e06c 100644
--- a/gcc-4.9/gcc/tree-ssa-loop-niter.c
+++ b/gcc-4.9/gcc/tree-ssa-loop-niter.c
@@ -3950,7 +3950,21 @@ loop_exits_before_overflow (tree base, tree step,
if (!CONVERT_EXPR_P (e) || !operand_equal_p (e, unsigned_base, 0))
continue;
e = TREE_OPERAND (e, 0);
- gcc_assert (operand_equal_p (e, base, 0));
+ /* It may still be possible to prove no overflow even if condition
+ "operand_equal_p (e, base, 0)" isn't satisfied here, like below
+ example:
+
+ e : ssa_var ; unsigned long type
+ base : (int) ssa_var
+ unsigned_base : (unsigned int) ssa_var
+
+ Unfortunately this is a rare case observed during GCC profiled
+ bootstrap. See PR66638 for more information.
+
+ For now, we just skip the possibility. */
+ if (!operand_equal_p (e, base, 0))
+ continue;
+
if (tree_int_cst_sign_bit (step))
{
code = LT_EXPR;