[Bug rtl-optimization/86334] wrong code with -march=athlon -mmemcpy-strategy=libcall:-1:noalign

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86334

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |hubicka at gcc dot gnu.org

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
The issue here is that g escapes as an argument to memcpy, but this is not
reported form local_variable_can_escape:

Breakpoint 1, local_variable_can_escape (decl=0x7fffe9ba3240) at
../../git/gcc/gcc/dse.c:910
910       if (TREE_ADDRESSABLE (decl))
Missing separate debuginfos, use: dnf debuginfo-install gmp-6.1.2-7.fc28.x86_64
isl-0.16.1-6.fc28.x86_64 libgcc-8.1.1-1.fc28.x86_64 libmpc-1.0.2-9.fc28.x86_64
libstdc++-8.1.1-1.fc28.x86_64 mpfr-3.1.6-1.fc28.x86_64
(gdb) p debug_generic_expr (decl)
g
$1 = void
(gdb) fin
Run till exit from #0  local_variable_can_escape (decl=0x7fffe9ba3240) at
../../git/gcc/gcc/dse.c:910
0x00000000013fb758 in can_escape (expr=0x7fffe9ba3240) at
../../git/gcc/gcc/dse.c:942
942                && local_variable_can_escape (base)))
Value returned is $2 = false

DSE just removes all stores to g as dead.

CC Honza.