cmd/compile: combine OR + NOT into ORN on PPC64

This shows up in a few crypto functions, and other assorted places. Change-Id: I5a7f4c25ddd4a6499dc295ef693b9fe43d2448ab Reviewed-on: https://go-review.googlesource.com/c/go/+/404057 Run-TryBot: Paul Murphy <[email protected]> TryBot-Result: Gopher Robot <[email protected]> Reviewed-by: Lynn Boger <[email protected]> Reviewed-by: David Chase <[email protected]> Reviewed-by: Russ Cox <[email protected]>
open-fork · May 4, 2022 · c570f0e · c570f0e
1 parent ffe48e0
commit c570f0e
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Showing 3 changed files with 28 additions and 1 deletion.
diff --git a/src/cmd/compile/internal/ssa/gen/PPC64.rules b/src/cmd/compile/internal/ssa/gen/PPC64.rules
@@ -381,8 +381,9 @@
 (OrB ...) => (OR ...)
 (Not x) => (XORconst [1] x)
 
-// Use ANDN for AND x NOT y
+// Merge logical operations
 (AND x (NOR y y)) => (ANDN x y)
+(OR x (NOR y y)) => (ORN x y)
 
 // Lowering comparisons
 (EqB x y)  => (ANDconst [1] (EQV x y))

diff --git a/src/cmd/compile/internal/ssa/rewritePPC64.go b/src/cmd/compile/internal/ssa/rewritePPC64.go
diff --git a/test/codegen/logic.go b/test/codegen/logic.go
@@ -22,3 +22,11 @@ func andWithUse(x, y int) int {
 	// use z by returning it
 	return z
 }
+
+// Verify (OR x (NOT y)) rewrites to (ORN x y) where supported
+func ornot(x, y int) int {
+	// ppc64:"ORN"
+	// ppc64le:"ORN"
+	z := x | ^y
+	return z
+}