From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1666) id 868C93858D37; Thu, 20 Jan 2022 15:50:57 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 868C93858D37 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Richard Biener To: gcc-cvs@gcc.gnu.org Subject: [gcc r12-6776] middle-end/100786 - constant folding from incompatible alias X-Act-Checkin: gcc X-Git-Author: Richard Biener X-Git-Refname: refs/heads/master X-Git-Oldrev: 62eb400b51f8a552320a250b3ac0b5d2ebd8927f X-Git-Newrev: 5c12507f5d0bc080e4f346af99824e039236e61c Message-Id: <20220120155057.868C93858D37@sourceware.org> Date: Thu, 20 Jan 2022 15:50:57 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Jan 2022 15:50:57 -0000 https://gcc.gnu.org/g:5c12507f5d0bc080e4f346af99824e039236e61c commit r12-6776-g5c12507f5d0bc080e4f346af99824e039236e61c Author: Richard Biener Date: Thu Jan 20 14:25:51 2022 +0100 middle-end/100786 - constant folding from incompatible alias The following avoids us ICEing doing constant folding from variables with aliases of different types. The issue appears both in folding and CCP and FRE can do more fancy stuff to still constant fold cases where the load is smaller than the initializer so defer it to there. 2022-01-20 Richard Biener PR middle-end/100786 * gimple-fold.cc (get_symbol_constant_value): Only return values of compatible type to the symbol. * gcc.dg/torture/pr100786.c: New testcase. Diff: --- gcc/gimple-fold.cc | 4 +++- gcc/testsuite/gcc.dg/torture/pr100786.c | 9 +++++++++ 2 files changed, 12 insertions(+), 1 deletion(-) diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc index 08d3cc214ff..3639aa20626 100644 --- a/gcc/gimple-fold.cc +++ b/gcc/gimple-fold.cc @@ -291,7 +291,9 @@ get_symbol_constant_value (tree sym) if (val) { val = canonicalize_constructor_val (unshare_expr (val), sym); - if (val && is_gimple_min_invariant (val)) + if (val + && is_gimple_min_invariant (val) + && useless_type_conversion_p (TREE_TYPE (sym), TREE_TYPE (val))) return val; else return NULL_TREE; diff --git a/gcc/testsuite/gcc.dg/torture/pr100786.c b/gcc/testsuite/gcc.dg/torture/pr100786.c new file mode 100644 index 00000000000..42f4e485593 --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr100786.c @@ -0,0 +1,9 @@ +/* { dg-do compile } */ + +const double a = 0; +extern int b __attribute__((alias("a"))); +void inc() { b++; } + +const int a2 = 0; +extern double b2 __attribute__((alias("a2"))); +void inc2() { b2+=1; }