Legalize bnot using xor with -1.

2018-05-05 11:01:49 -05:00
parent bb612af37a
commit 5b69930e03
2 changed files with 10 additions and 1 deletions
--- a/lib/codegen/meta/base/legalize.py
+++ b/lib/codegen/meta/base/legalize.py
@@ -252,6 +252,14 @@ for inst_not,      inst in [
                a << inst(x, a1)
            ))

+# Expand bnot using xor.
+expand.legalize(
+        a << bnot(x),
+        Rtl(
+            y << iconst(imm64(-1)),
+            a << bxor(x, y)
+        ))
+
 # Floating-point sign manipulations.
 for ty,             minus_zero in [
        (types.f32, f32const(ieee32.bits(0x80000000))),