diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index 740ba8606a..4adbc9e45f 100644
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -1386,9 +1386,9 @@
 
 // recognize runtime.newobject and don't Zero/Nilcheck it
 (Zero (Load (OffPtr [c] (SP)) mem) mem)
-        && mem.Op == OpStaticCall
+	&& mem.Op == OpStaticCall
 	&& isSameSym(mem.Aux, "runtime.newobject")
-	&& c == config.ctxt.FixedFrameSize() + config.PtrSize // offset of return value
+	&& c == config.ctxt.FixedFrameSize() + config.RegSize // offset of return value
 	-> mem
 // nil checks just need to rewrite to something useless.
 // they will be deadcode eliminated soon afterwards.
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index f17bf3343c..0709eb89bb 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -17210,7 +17210,7 @@ func rewriteValuegeneric_OpZero(v *Value, config *Config) bool {
 	b := v.Block
 	_ = b
 	// match: (Zero (Load (OffPtr [c] (SP)) mem) mem)
-	// cond: mem.Op == OpStaticCall 	&& isSameSym(mem.Aux, "runtime.newobject") 	&& c == config.ctxt.FixedFrameSize() + config.PtrSize
+	// cond: mem.Op == OpStaticCall 	&& isSameSym(mem.Aux, "runtime.newobject") 	&& c == config.ctxt.FixedFrameSize() + config.RegSize
 	// result: mem
 	for {
 		v_0 := v.Args[0]
@@ -17230,7 +17230,7 @@ func rewriteValuegeneric_OpZero(v *Value, config *Config) bool {
 		if mem != v.Args[1] {
 			break
 		}
-		if !(mem.Op == OpStaticCall && isSameSym(mem.Aux, "runtime.newobject") && c == config.ctxt.FixedFrameSize()+config.PtrSize) {
+		if !(mem.Op == OpStaticCall && isSameSym(mem.Aux, "runtime.newobject") && c == config.ctxt.FixedFrameSize()+config.RegSize) {
 			break
 		}
 		v.reset(OpCopy)