From 75f8900159133ce069ef1d2edf3b67c7bc82e305 Mon Sep 17 00:00:00 2001 From: Jakub Jelinek Date: Tue, 27 Apr 2021 14:47:54 +0200 Subject: match.pd: Add some __builtin_ctz (x) cmp cst simplifications [PR95527] 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. 2021-04-27 Jakub Jelinek 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. --- gcc/generic-match-head.c | 1 + 1 file changed, 1 insertion(+) (limited to 'gcc/generic-match-head.c') diff --git a/gcc/generic-match-head.c b/gcc/generic-match-head.c index a063512..f426208 100644 --- a/gcc/generic-match-head.c +++ b/gcc/generic-match-head.c @@ -37,6 +37,7 @@ along with GCC; see the file COPYING3. If not see #include "gimplify.h" #include "optabs-tree.h" #include "dbgcnt.h" +#include "tm.h" /* Routine to determine if the types T1 and T2 are effectively the same for GENERIC. If T1 or T2 is not a type, the test -- cgit v1.1