diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index f9566368c0..c3007781d6 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -1631,7 +1631,7 @@ func mergePPC64ClrlsldiSrd(sld, srd int64) int64 {
 	if v1&mask_3 != 0 {
 		return 0
 	}
-	return encodePPC64RotateMask(int64(r_3-32), int64(mask_3), 32)
+	return encodePPC64RotateMask(int64(r_3&31), int64(mask_3), 32)
 }
 
 // Test if a RLWINM feeding into a CLRLSLDI can be merged into RLWINM.  Return
diff --git a/test/codegen/shift.go b/test/codegen/shift.go
index dd91a1db98..6a2a6c40cd 100644
--- a/test/codegen/shift.go
+++ b/test/codegen/shift.go
@@ -453,7 +453,7 @@ func checkMergedShifts32(a [256]uint32, b [256]uint64, u uint32, v uint32) {
 	b[2] = b[v>>25]
 }
 
-func checkMergedShifts64(a [256]uint32, b [256]uint64, v uint64) {
+func checkMergedShifts64(a [256]uint32, b [256]uint64, c [256]byte, v uint64) {
 	// ppc64x: -"CLRLSLDI", "RLWNM\t[$]10, R[0-9]+, [$]22, [$]29, R[0-9]+"
 	a[0] = a[uint8(v>>24)]
 	// ppc64x: "SRD", "CLRLSLDI", -"RLWNM"
@@ -474,6 +474,10 @@ func checkMergedShifts64(a [256]uint32, b [256]uint64, v uint64) {
 	b[1] = b[(v>>20)&0xFF]
 	// ppc64x: "RLWNM", -"SLD"
 	b[2] = b[((uint64((uint32(v) >> 21)) & 0x3f) << 4)]
+	// ppc64x: "RLWNM\t[$]11, R[0-9]+, [$]10, [$]15"
+	c[0] = c[((v>>5)&0x3F)<<16]
+	// ppc64x: "RLWNM\t[$]0, R[0-9]+, [$]19, [$]24"
+	c[1] = c[((v>>7)&0x3F)<<7]
 }
 
 func checkShiftMask(a uint32, b uint64, z []uint32, y []uint64) {