diff --git a/src/cmd/compile/internal/ssa/_gen/generic.rules b/src/cmd/compile/internal/ssa/_gen/generic.rules
index 10da571988..d72824c4bf 100644
--- a/src/cmd/compile/internal/ssa/_gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/_gen/generic.rules
@@ -2070,7 +2070,7 @@
 // Turn known-size calls to memclrNoHeapPointers into a Zero.
 // Note that we are using types.Types[types.TUINT8] instead of sptr.Type.Elem() - see issue 55122 and CL 431496 for more details.
 (SelectN [0] call:(StaticCall {sym} sptr (Const(64|32) [c]) mem))
-  && isInlinableMemclr(config)
+  && isInlinableMemclr(config, int64(c))
   && isSameCall(sym, "runtime.memclrNoHeapPointers")
   && call.Uses == 1
   && clobber(call)
diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index 0cf7917ec6..c56447d336 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -1365,10 +1365,16 @@ func zeroUpper56Bits(x *Value, depth int) bool {
 	return false
 }
 
-func isInlinableMemclr(c *Config) bool {
+func isInlinableMemclr(c *Config, sz int64) bool {
 	// TODO: expand this check to allow other architectures
 	// see CL 454255 and issue 56997
-	return c.arch == "amd64" || c.arch == "arm64"
+	switch c.arch {
+	case "amd64", "arm64":
+		return true
+	case "ppc64le", "ppc64":
+		return sz < 512
+	}
+	return false
 }
 
 // isInlinableMemmove reports whether the given arch performs a Move of the given size
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index b81d093119..49a721b5f2 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -26411,7 +26411,7 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
 		return true
 	}
 	// match: (SelectN [0] call:(StaticCall {sym} sptr (Const64 [c]) mem))
-	// cond: isInlinableMemclr(config) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)
+	// cond: isInlinableMemclr(config, int64(c)) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)
 	// result: (Zero {types.Types[types.TUINT8]} [int64(c)] sptr mem)
 	for {
 		if auxIntToInt64(v.AuxInt) != 0 {
@@ -26429,7 +26429,7 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
 			break
 		}
 		c := auxIntToInt64(call_1.AuxInt)
-		if !(isInlinableMemclr(config) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)) {
+		if !(isInlinableMemclr(config, int64(c)) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)) {
 			break
 		}
 		v.reset(OpZero)
@@ -26439,7 +26439,7 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
 		return true
 	}
 	// match: (SelectN [0] call:(StaticCall {sym} sptr (Const32 [c]) mem))
-	// cond: isInlinableMemclr(config) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)
+	// cond: isInlinableMemclr(config, int64(c)) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)
 	// result: (Zero {types.Types[types.TUINT8]} [int64(c)] sptr mem)
 	for {
 		if auxIntToInt64(v.AuxInt) != 0 {
@@ -26457,7 +26457,7 @@ func rewriteValuegeneric_OpSelectN(v *Value) bool {
 			break
 		}
 		c := auxIntToInt32(call_1.AuxInt)
-		if !(isInlinableMemclr(config) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)) {
+		if !(isInlinableMemclr(config, int64(c)) && isSameCall(sym, "runtime.memclrNoHeapPointers") && call.Uses == 1 && clobber(call)) {
 			break
 		}
 		v.reset(OpZero)
diff --git a/test/codegen/slices.go b/test/codegen/slices.go
index e3be6bd76b..a38fe77e3f 100644
--- a/test/codegen/slices.go
+++ b/test/codegen/slices.go
@@ -47,7 +47,7 @@ func SliceExtensionConst(s []int) []int {
 	// amd64:-`.*runtime\.makeslice`
 	// amd64:-`.*runtime\.panicmakeslicelen`
 	// amd64:"MOVUPS\tX15"
-	// ppc64x:`.*runtime\.memclrNoHeapPointers`
+	// ppc64x:-`.*runtime\.memclrNoHeapPointers`
 	// ppc64x:-`.*runtime\.makeslice`
 	// ppc64x:-`.*runtime\.panicmakeslicelen`
 	return append(s, make([]int, 1<<2)...)
@@ -58,7 +58,7 @@ func SliceExtensionConstInt64(s []int) []int {
 	// amd64:-`.*runtime\.makeslice`
 	// amd64:-`.*runtime\.panicmakeslicelen`
 	// amd64:"MOVUPS\tX15"
-	// ppc64x:`.*runtime\.memclrNoHeapPointers`
+	// ppc64x:-`.*runtime\.memclrNoHeapPointers`
 	// ppc64x:-`.*runtime\.makeslice`
 	// ppc64x:-`.*runtime\.panicmakeslicelen`
 	return append(s, make([]int, int64(1<<2))...)
@@ -69,7 +69,7 @@ func SliceExtensionConstUint64(s []int) []int {
 	// amd64:-`.*runtime\.makeslice`
 	// amd64:-`.*runtime\.panicmakeslicelen`
 	// amd64:"MOVUPS\tX15"
-	// ppc64x:`.*runtime\.memclrNoHeapPointers`
+	// ppc64x:-`.*runtime\.memclrNoHeapPointers`
 	// ppc64x:-`.*runtime\.makeslice`
 	// ppc64x:-`.*runtime\.panicmakeslicelen`
 	return append(s, make([]int, uint64(1<<2))...)
@@ -80,12 +80,20 @@ func SliceExtensionConstUint(s []int) []int {
 	// amd64:-`.*runtime\.makeslice`
 	// amd64:-`.*runtime\.panicmakeslicelen`
 	// amd64:"MOVUPS\tX15"
-	// ppc64x:`.*runtime\.memclrNoHeapPointers`
+	// ppc64x:-`.*runtime\.memclrNoHeapPointers`
 	// ppc64x:-`.*runtime\.makeslice`
 	// ppc64x:-`.*runtime\.panicmakeslicelen`
 	return append(s, make([]int, uint(1<<2))...)
 }
 
+// On ppc64x continue to use memclrNoHeapPointers
+// for sizes >= 512.
+func SliceExtensionConst512(s []int) []int {
+	// amd64:-`.*runtime\.memclrNoHeapPointers`
+	// ppc64x:`.*runtime\.memclrNoHeapPointers`
+	return append(s, make([]int, 1<<9)...)
+}
+
 func SliceExtensionPointer(s []*int, l int) []*int {
 	// amd64:`.*runtime\.memclrHasPointers`
 	// amd64:-`.*runtime\.makeslice`