On 05/01/2017 11:16 AM, Steve Ellcey wrote: > This is a resubmittal of an earlier patch > (https://gcc.gnu.org/ml/gcc-patches/2017-02/msg00203.html) to improve the > use of ccmp (conditional compare) on aarch64. I made a couple of tweaks > after the first submittal and retested now that we are back in stage 1. > > Most of the changes are restructuring the code to allow the change and do > not affect the actual output. The actual behavour change is in > ccmp_tree_comparison_p where we recoginize a boolean variable as well > as a compare expression as code that can be done with a conditionial > compare and in get_compare_parts where we treat a boolean variable X > as 'X != 0' and generate that comparision. > > Since the code in ccmp.c is ony used when TARGET_GEN_CCMP_FIRST is set > and TARGET_GEN_CCMP_FIRST is only set for aarch64 this change will only > affect aarch64. > > Tested with no regressions and a new test is added to verify that we > generate a ccmp instruction with the change. I ran the SPEC2006 int > tests and got a .02 increase in the SPECmark on a ThunderX box. The > biggest increases were in mcf and astar. One test, xlancbmk, did slow > down but the overall SPEC result was a speedup. > > OK for checkin? > > Steve Ellcey > sell...@cavium.com > > > GCC ChangeLog: > > 2017-05-01 Steve Ellcey <sell...@cavium.com> > > * ccmp.c (ccmp_tree_comparison_p): New function. > (ccmp_candidate_p): Update to use above function. > (get_compare_parts): New function. > (expand_ccmp_next): Update to use new functions. > (expand_ccmp_expr_1): Take tree arg instead of gimple, update to use > new functions. > (expand_ccmp_expr): Pass tree instead of gimple to expand_ccmp_expr_1, > take mode as argument. > * ccmp.h (expand_ccmp_expr): Add mode as argument. > * expr.c (expand_expr_real_1): Pass mode as argument. > > GCC Testsuite ChangeLog: > > > 2017-05-01 Steve Ellcey <sell...@cavium.com> > > * gcc.target/aarch64/ccmp_2.c: New test. > > > gcc.ccmp.patch > > > diff --git a/gcc/ccmp.c b/gcc/ccmp.c > index 92ca133..4fa3ebd 100644 > --- a/gcc/ccmp.c > +++ b/gcc/ccmp.c > @@ -38,6 +38,29 @@ along with GCC; see the file COPYING3. If not see > #include "ccmp.h" > #include "predict.h" > > +/* Check whether T is a simple boolean variable or a SSA name > + set by a comparison operator in the same basic block. */ > +static bool > +ccmp_tree_comparison_p (tree t, basic_block bb) > +{ > + gimple *g = get_gimple_for_ssa_name (t); > + tree_code tcode; > + > + /* If we have a boolean variable allow it and generate a compare > + to zero reg when expanding. */ > + if (!g) > + return (TREE_CODE (TREE_TYPE (t)) == BOOLEAN_TYPE); Depending on how you use T, you might be better off checking T's range and considering anything with the [0,1] range as a boolean. That would also pick up the case where T was set via a comparison, or the output of a PHI with arguments that are all [0,1], etc. I've found that to be a useful improvement in a couple places.
See ssa_name_has_boolean_range. I don't consider it a requirement for this patch to go forward, but more something you might want to investigate as a future improvement. OK for the trunk. Sorry about the delay. jeff
