On Sun, May 31, 2020 at 4:10 PM H.J. Lu <hjl.to...@gmail.com> wrote: > > We used to expand memcmp to "repz cmpsb" via cmpstrnsi. It was changed > by > > commit 9b0f6f5e511ca512e4faeabc81d2fd3abad9b02f > Author: Nick Clifton <ni...@redhat.com> > Date: Fri Aug 12 16:26:11 2011 +0000 > > builtins.c (expand_builtin_memcmp): Do not use cmpstrnsi pattern. > > * builtins.c (expand_builtin_memcmp): Do not use cmpstrnsi > pattern. > * doc/md.texi (cmpstrn): Note that the comparison stops if both > fetched bytes are zero. > (cmpstr): Likewise. > (cmpmem): Note that the comparison does not stop if both of the > fetched bytes are zero. > > Duplicate the cmpstrn pattern for cmpmem and expand cmpmem to "repz cmpsb" > for -minline-all-stringops. The only difference is that the length > argument of cmpmem is guaranteed to be less than or equal to lengths of > 2 memory areas. Since cmpmem expander may pass the actual string length > directly to cmpstrnqi patterns. Pass a copy of the string length to > cmpstrnqi patterns to avoid changing the actual string length by cmpstrnqi > patterns. > > Tested on Linux/x86 and Linux/x86-64. OK for master? > > H.J. Lu (2): > x86: Pass a copy of the string length to cmpstrnqi > x86: Add cmpmemsi for -minline-all-stringops > > gcc/config/i386/i386-expand.c | 84 ++++++++++++++ > gcc/config/i386/i386-protos.h | 1 + > gcc/config/i386/i386.md | 80 ++++--------- > gcc/testsuite/gcc.target/i386/pr95151-1.c | 17 +++ > gcc/testsuite/gcc.target/i386/pr95151-2.c | 10 ++ > gcc/testsuite/gcc.target/i386/pr95151-3.c | 18 +++ > gcc/testsuite/gcc.target/i386/pr95151-4.c | 11 ++ > gcc/testsuite/gcc.target/i386/pr95443-1.c | 130 ++++++++++++++++++++++ > gcc/testsuite/gcc.target/i386/pr95443-2.c | 79 +++++++++++++ > 9 files changed, 371 insertions(+), 59 deletions(-) > create mode 100644 gcc/testsuite/gcc.target/i386/pr95151-1.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr95151-2.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr95151-3.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr95151-4.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr95443-1.c > create mode 100644 gcc/testsuite/gcc.target/i386/pr95443-2.c >
PING: https://gcc.gnu.org/pipermail/gcc-patches/2020-May/546920.html https://gcc.gnu.org/pipermail/gcc-patches/2020-May/546921.html -- H.J.
