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)([email protected]): [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 <[email protected]>
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")
