[Bug tree-optimization/91597] [9/10 Regression] GCC miscompiles a branch depending on a pointer tag
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597 Jakub Jelinek changed: What|Removed |Added Status|NEW |RESOLVED Resolution|--- |FIXED --- Comment #6 from Jakub Jelinek --- Fixed.
[Bug tree-optimization/91597] [9/10 Regression] GCC miscompiles a branch depending on a pointer tag
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597 --- Comment #5 from Jakub Jelinek --- Author: jakub Date: Tue Sep 3 16:55:31 2019 New Revision: 275345 URL: https://gcc.gnu.org/viewcvs?rev=275345=gcc=rev Log: PR tree-optimization/91597 * tree-vrp.c (extract_range_from_binary_expr): Remove unsafe BIT_AND_EXPR optimization for pointers, even if both operand ranges don't include NULL, the result can be NULL. * gcc.c-torture/execute/pr91597.c: New test. Added: branches/gcc-9-branch/gcc/testsuite/gcc.c-torture/execute/pr91597.c Modified: branches/gcc-9-branch/gcc/ChangeLog branches/gcc-9-branch/gcc/testsuite/ChangeLog branches/gcc-9-branch/gcc/tree-vrp.c
[Bug tree-optimization/91597] [9/10 Regression] GCC miscompiles a branch depending on a pointer tag
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597 --- Comment #4 from Jakub Jelinek --- Author: jakub Date: Tue Sep 3 07:50:46 2019 New Revision: 275330 URL: https://gcc.gnu.org/viewcvs?rev=275330=gcc=rev Log: PR tree-optimization/91597 * tree-vrp.c (extract_range_from_binary_expr): Remove unsafe BIT_AND_EXPR optimization for pointers, even if both operand ranges don't include NULL, the result can be NULL. * gcc.c-torture/execute/pr91597.c: New test. Added: trunk/gcc/testsuite/gcc.c-torture/execute/pr91597.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-vrp.c
[Bug tree-optimization/91597] [9/10 Regression] GCC miscompiles a branch depending on a pointer tag
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597 --- Comment #3 from Wojciech Nawrocki --- Workaround: -fdisable-tree-ifcombine turns off the broken optimization pass
[Bug tree-optimization/91597] [9/10 Regression] GCC miscompiles a branch depending on a pointer tag
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597
--- Comment #2 from Jakub Jelinek ---
As mentioned by Richi,
else if (code == BIT_AND_EXPR)
{
/* For pointer types, we are really only interested in asserting
whether the expression evaluates to non-NULL. */
if (!range_includes_zero_p () && !range_includes_zero_p ())
vr->set_nonzero (expr_type);
is incorrect, even when both pointer value ranges are non-zero, the result of
BIT_AND_EXPR can be zero, as can be seen on this testcase. The first argument
being non-NULL as dereferenced, the other argument constant 1B, the pointer
aligned and thus actually & 1 always zero, not always non-zero, but even if it
would not be always aligned, it could be sometimes zero and sometimes not.
[Bug tree-optimization/91597] [9/10 Regression] GCC miscompiles a branch depending on a pointer tag
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91597 Jakub Jelinek changed: What|Removed |Added Status|UNCONFIRMED |NEW Last reconfirmed||2019-08-29 CC||jakub at gcc dot gnu.org Target Milestone|--- |9.3 Ever confirmed|0 |1 --- Comment #1 from Jakub Jelinek --- Started with r263842, likely latent before that.
