On 3/29/19 1:47 PM, Jakub Jelinek wrote: > Hi! > > The following patch improves the last 8 cases (both -m64 and ia32) > that were using RMW cycle, for xor we actually emit > new = old ^ other; new != old > rather than > new = old ^ other; new != 0 > and thus the peephole2 needs to recognize that too. > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > 2019-03-29 Jakub Jelinek <ja...@redhat.com> > > PR rtl-optimization/89865 > * config/i386/i386.md: Add peepholes for z = x; x ^= y; x != z. > > * gcc.target/i386/pr49095.c: Don't expect any RMW sequences. Ewwww. But OK.
jeff
