http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57003
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|WAITING |NEW Component|middle-end |rtl-optimization Target Milestone|--- |4.8.1 Summary|gcc-4.8.0 breaks -O2 |[4.8/4.9 Regression] |optimization with Wine(64) |gcc-4.8.0 breaks -O2 |- links/info/bisect of |optimization with Wine(64) |commits included |- links/info/bisect of | |commits included --- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-24 16:50:21 UTC --- Ah, ok, I can see it. To look at 22354 it helps to sed -i 's/^# .*$//', then look for 22354 in the dump. Seems the code is still correct at *.ce3 pass, Bernd's optimization kicks in during RA time before that and the pseudo holding buffer is assigned to %rdi before the call memcpy and assumed to live in %rax right after the call. But cprop_hardreg breaks this, changes the %rax after the memcpy call into %rdi, even when %rdi is call clobbered register, and even the call pattern contains (clobber (reg:DI 5 di)) and REG_DEAD note for the same register.