add reminder by a power of two peephole rule

2020-07-03 09:44:59 +03:00
parent d87ada209c
commit d839d83f7e
2 changed files with 5 additions and 0 deletions
--- a/cranelift/codegen/src/preopt.peepmatic
+++ b/cranelift/codegen/src/preopt.peepmatic
@@ -191,3 +191,8 @@
 (=> (when (udiv_imm $C $x)
          (is-power-of-two $C))
    (ushr_imm $(log2 $C) $x))
+
+;; Reminder by a power of two -> bitwise and with decreased by one constant.
+(=> (when (urem_imm $C $x)
+          (is-power-of-two $C))
+    (band_imm $(iadd -1 $C) $x))
--- a/cranelift/codegen/src/preopt.serialized
+++ b/cranelift/codegen/src/preopt.serialized