This change unnecessarily pessimizes some cases.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2017-05-03 Richard Biener <rguent...@suse.de>
Revert
PR tree-optimization/80492
* tree-ssa-alias.c (decl_refs_may_alias_p): Handle
compare_base_decls returning dont-know properly.
Index: gcc/tree-ssa-alias.c
===================================================================
--- gcc/tree-ssa-alias.c (revision 247492)
+++ gcc/tree-ssa-alias.c (working copy)
@@ -1096,16 +1096,13 @@ decl_refs_may_alias_p (tree ref1, tree b
{
gcc_checking_assert (DECL_P (base1) && DECL_P (base2));
- int cmp = compare_base_decls (base1, base2);
-
/* If both references are based on different variables, they cannot alias.
*/
- if (cmp == 0)
+ if (compare_base_decls (base1, base2) == 0)
return false;
/* If both references are based on the same variable, they cannot alias if
the accesses do not overlap. */
- if (cmp == 1
- && !ranges_overlap_p (offset1, max_size1, offset2, max_size2))
+ if (!ranges_overlap_p (offset1, max_size1, offset2, max_size2))
return false;
/* For components with variable position, the above test isn't sufficient,
