This ports the clrsb builtin part of builtin_zero_pattern
to match.pd. A simple pattern to port.
OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
gcc/ChangeLog:
* match.pd (a != 0 ? CLRSB(a) : CST -> CLRSB(a)): New
pattern.
---
gcc/match.pd | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/gcc/match.pd b/gcc/match.pd
index 0e782cde71d..bf918ba70ce 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7787,6 +7787,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(cond (ne @0 integer_zerop@1) (func@4 (convert? @2)) integer_zerop@3)
@4))
+/* a != 0 ? FUN(a) : CST -> Fun(a) for some CLRSB builtins
+ where CST is precision-1. */
+(for func (CLRSB)
+ (simplify
+ (cond (ne @0 integer_zerop@1) (func@5 (convert?@4 @2)) INTEGER_CST@3)
+ (if (wi::to_widest (@3) == TYPE_PRECISION (TREE_TYPE (@4)) - 1)
+ @5)))
+
#if GIMPLE
/* a != 0 ? CLZ(a) : CST -> .CLZ(a) where CST is the result of the internal
function for 0. */
(for func (CLZ)
--
2.31.1
