On Thu, Dec 23, 2021 at 10:35 AM Roger Sayle <ro...@nextmovesoftware.com> wrote: > > Hi Uros, > > A huge thanks for the list of suggested improvements to the -Oz related > patches. > I've combined them altogether in the submission below, which makes sense now > that everything is implemented using peephole2. The implementation of > push/pop via peephole2 is exactly as you've suggested, also checking that the > immediate value isn't zero (the value -1 is still a size win over OR), and > extended > to include HImode (where it is a win), but not QImode (where it isn't). > > For writes to memory, I've extended *mov<mode>_or to allow memory destinations > and HImode, but I've introduced a new *mov<mode>_and for writing zero to > memory, > rather than complicate/overload *mov<mode>_xor (for example, it doesn't take > an > immediate). In this form, only a single peephole2 is needed, that adds a > clobber to > the instruction if the flags are dead. > > This patch has been tested on x86_64-pc-linux-gnu with make bootstrap > and make -k check with no new failures, and the new testcase checked > both with and without -m32. Ok for mainline? > > > 2021-12-23 Roger Sayle <ro...@nextmovesoftware.com> > Uroš Bizjak <ubiz...@gmail.com> > > gcc/ChangeLog > PR target/103773 > * config/i386/i386.md (*mov<mode>_and): New define_insn for > writing a zero to memory using AND. > (*mov<mode>_or): Extend to allow memory destination and HImode. > (*movdi_internal): Remove -Oz push/pop optimization from here. > (*movsi_internal): Likewise. > (peephole2): Perform -Oz push/pop optimization here, only for > register destinations, values other than zero, and in functions > that don't used the red zone. > (peephole2): With -Oz, convert writes of 0 or -1 to memory into > their clobber forms, i.e. *mov<mode>_and and *mov<mode>_or resp. > > gcc/testsuite/ChangeLog > PR target/103773 > * gcc.target/pr103773-2.c: New test case. > * gcc.target/pr103773.c: New test case.
OK, but please add a small comment above new peephole2 patterns. Thanks, Uros.
