On Tue, Feb 02, 2021 at 07:40:02PM +0100, Jakub Jelinek via Gcc-patches wrote: > On Tue, Feb 02, 2021 at 11:39:30AM -0700, Jeff Law wrote: > > > This patch adds some ctz simplifications (e.g. ctz (x) >= 3 can be done by > > > testing if the low 3 bits are zero, etc.). > > > > > > In addition, I've noticed that in the CLZ case, the > > > #ifdef CLZ_DEFINED_VALUE_AT_ZERO don't really work as intended, they > > > are evaluated during genmatch and the macro is not defined then > > > (but, because of the missing tm.h includes it isn't defined in > > > gimple-match.c or generic-match.c either). And when tm.h is included, > > > defaults.h is included which defines a fallback version of that macro. > > > > > > For GCC 12, I wonder if it wouldn't be better to say in addition to > > > __builtin_c[lt]z* > > > is always UB at zero that it would be undefined for .C[LT]Z ifn too if it > > > has just one operand and use a second operand to be the constant we expect > > > at zero. > > > > > > Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? > > > > > > 2021-01-16 Jakub Jelinek <ja...@redhat.com> > > > > > > PR tree-optimization/95527 > > > * generic-match-head.c: Include tm.h. > > > * gimple-match-head.c: Include tm.h. > > > * match.pd (CLZ == INTEGER_CST): Don't use > > > #ifdef CLZ_DEFINED_VALUE_AT_ZERO, only test CLZ_DEFINED_VALUE_AT_ZERO > > > if clz == CFN_CLZ. Add missing val declaration. > > > (CTZ cmp CST): New simplifications. > > > > > > * gcc.dg/tree-ssa/pr95527-2.c: New test. > > Similarly. I'd lean towards deferring to gcc-12. > > Ok, will repost at the start of stage1 then (for both).
Ok for trunk now? https://gcc.gnu.org/pipermail/gcc-patches/2021-January/563711.html Jakub
