https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100685
Martin Liška <marxin at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |INVALID Status|ASSIGNED |RESOLVED --- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> --- (In reply to Martin Sebor from comment #0) > The #pragma GCC push_options in the program below should prevent the folding > of the strlen() call in g() but doesn't. This has changed in GCC 11 (GCC 10 > behaves as expected). The dump shows that the optimize attribute has both > optimization options, -O1 as well as -O2. That also seems unexpected but it > has not changed between 10 and 11. There's a change that caused that: r11-6922-gefc9ccbfd0ca4da6(27 Jan 2021 10:08)(ja...@redhat.com): [took: 0.596s] result: FAILED (1) varpool: Restore GENERIC TREE_READONLY automatic var optimization [PR7260] In 4.8 and earlier we used to fold the following to 0 during GENERIC folding, but we don't do that anymore because ctor_for_folding etc. has been turned into a GIMPLE centric API, but as the testcase shows, it is invoked even during GENERIC folding and there the automatic vars still should have meaningful initializers. I've verified that the C++ FE drops TREE_READONLY on automatic vars with const qualified types if they require non-constant (runtime) initialization. 2021-01-27 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/97260 * varpool.c: Include tree-pass.h. (ctor_for_folding): In GENERIC return DECL_INITIAL for TREE_READONLY non-TREE_SIDE_EFFECTS automatic variables. * gcc.dg/tree-ssa/pr97260.c: New test. So the code snippet is optimized out even with -O1. So you should use: #pragma GCC optimize ("0")