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RFC: PATCH to pointer_int_sum vs. pointer-arith-10.c
- From: Jason Merrill <jason at redhat dot com>
- To: Richard Biener <richard dot guenther at gmail dot com>
- Cc: gcc-patches List <gcc-patches at gcc dot gnu dot org>
- Date: Tue, 20 Oct 2015 09:10:31 -1000
- Subject: RFC: PATCH to pointer_int_sum vs. pointer-arith-10.c
- Authentication-results: sourceware.org; auth=none
I made this change on the delayed folding branch and then noticed that
it broke pointer-arith-10.c, which you added to the testsuite. The
patch changes the -original dump from
return (char *) ((sizetype) p + (sizetype) i);
to
return (char *) i + (sizetype) p;
It's not clear to me why the former should be preferred. Any thoughts?
Jason
commit 798829561671959e9e49965eb8c1b137b48751e0
Author: Jason Merrill <jason@redhat.com>
Date: Tue Oct 20 00:39:03 2015 -1000
* c-common.c (pointer_int_sum): Fold the MULT_EXPR.
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 1c75921..f957018 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -4849,9 +4849,8 @@ pointer_int_sum (location_t loc, enum tree_code resultcode,
for the pointer operation and disregard an overflow that occurred only
because of the sign-extension change in the latter conversion. */
{
- tree t = build_binary_op (loc,
- MULT_EXPR, intop,
- convert (TREE_TYPE (intop), size_exp), 1);
+ tree t = fold_build2_loc (loc, MULT_EXPR, TREE_TYPE (intop), intop,
+ convert (TREE_TYPE (intop), size_exp));
intop = convert (sizetype, t);
if (TREE_OVERFLOW_P (intop) && !TREE_OVERFLOW (t))
intop = wide_int_to_tree (TREE_TYPE (intop), intop);