https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79593
Uroš Bizjak <ubizjak at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords|missed-optimization |ra
Status|WAITING |NEW
CC| |vmakarov at gcc dot gnu.org
Component|target |rtl-optimization
--- Comment #15 from Uroš Bizjak <ubizjak at gmail dot com> ---
For the remaining issue:
mov eax, DWORD PTR [eax+4]
...
mov DWORD PTR [esp], eax # worse than v6: spills to stack!
fld DWORD PTR [esp] # instead of 'fsubr DWORD PTR [eax+4]'
fsubrp st(2), st
register allocator doesn't figure out that it loaded eax from [eax+4] a couple
of insns above - instead of a spill, it can access the value from the same
location.
This is a RA regression from gcc-5.
