3 files changed, 15 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/ssa/_gen/PPC64.rules b/src/cmd/compile/internal/ssa/_gen/PPC64.rules
index 97e592fd7e..4c4f7c8c17 100644
--- a/src/cmd/compile/internal/ssa/_gen/PPC64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/PPC64.rules
@@ -559,6 +559,7 @@
 (NOR (MOVDconst [c]) (MOVDconst [d])) => (MOVDconst [^(c|d)])
 
 // Discover consts
+(AND x (MOVDconst [-1])) => x
 (AND x (MOVDconst [c])) && isU16Bit(c) => (Select0 (ANDCCconst [c] x))
 (XOR x (MOVDconst [c])) && isU32Bit(c) => (XORconst [c] x)
 (OR x (MOVDconst [c])) && isU32Bit(c) => (ORconst [c] x)
diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index efbaae4d46..eebedea68c 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -1478,7 +1478,7 @@ func encodePPC64RotateMask(rotate, mask, nbits int64) int64 {
 
 	// Determine boundaries and then decode them
 	if mask == 0 || ^mask == 0 || rotate >= nbits {
-		panic("Invalid PPC64 rotate mask")
+		panic(fmt.Sprintf("invalid PPC64 rotate mask: %x %d %d", uint64(mask), rotate, nbits))
 	} else if nbits == 32 {
 		mb = bits.LeadingZeros32(uint32(mask))
 		me = 32 - bits.TrailingZeros32(uint32(mask))
diff --git a/src/cmd/compile/internal/ssa/rewritePPC64.go b/src/cmd/compile/internal/ssa/rewritePPC64.go
index d1c0c2b07f..2bcc27fbc8 100644
--- a/src/cmd/compile/internal/ssa/rewritePPC64.go
+++ b/src/cmd/compile/internal/ssa/rewritePPC64.go
@@ -4226,6 +4226,19 @@ func rewriteValuePPC64_OpPPC64AND(v *Value) bool {
 		}
 		break
 	}
+	// match: (AND x (MOVDconst [-1]))
+	// result: x
+	for {
+		for _i0 := 0; _i0 <= 1; _i0, v_0, v_1 = _i0+1, v_1, v_0 {
+			x := v_0
+			if v_1.Op != OpPPC64MOVDconst || auxIntToInt64(v_1.AuxInt) != -1 {
+				continue
+			}
+			v.copyOf(x)
+			return true
+		}
+		break
+	}
 	// match: (AND x (MOVDconst [c]))
 	// cond: isU16Bit(c)
 	// result: (Select0 (ANDCCconst [c] x))