diff --git a/src/cmd/compile/internal/ssa/_gen/AMD64.rules b/src/cmd/compile/internal/ssa/_gen/AMD64.rules
index 7840600ef6..aac6873d28 100644
--- a/src/cmd/compile/internal/ssa/_gen/AMD64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/AMD64.rules
@@ -1468,6 +1468,7 @@
   && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off()))
   && a.Val() == 0
   && c.Val() == 0
+  && setPos(v, x.Pos)
   && clobber(x)
   => (MOVOstoreconst [makeValAndOff(0,a.Off())] {s} p0 mem)
 (MOVQstoreconst [a] {s} p0 x:(MOVQstoreconst [c] {s} p1 mem))
@@ -1476,6 +1477,7 @@
   && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off()))
   && a.Val() == 0
   && c.Val() == 0
+  && setPos(v, x.Pos)
   && clobber(x)
   => (MOVOstoreconst [makeValAndOff(0,a.Off())] {s} p0 mem)
 
diff --git a/src/cmd/compile/internal/ssa/_gen/ARM64.rules b/src/cmd/compile/internal/ssa/_gen/ARM64.rules
index 227ec5d610..c5ee0285d9 100644
--- a/src/cmd/compile/internal/ssa/_gen/ARM64.rules
+++ b/src/cmd/compile/internal/ssa/_gen/ARM64.rules
@@ -485,8 +485,8 @@
 			(STP [16] dst (Select0 <typ.UInt64> (LDP [16] src mem)) (Select1 <typ.UInt64> (LDP [16] src mem))
 				(STP dst (Select0 <typ.UInt64> (LDP src mem)) (Select1 <typ.UInt64> (LDP src mem)) mem))))
 
-(MOVDstorezero {s} [i] ptr x:(MOVDstorezero {s} [i+8] ptr mem)) && x.Uses == 1 && clobber(x) => (MOVQstorezero {s} [i] ptr mem)
-(MOVDstorezero {s} [i] ptr x:(MOVDstorezero {s} [i-8] ptr mem)) && x.Uses == 1 && clobber(x) => (MOVQstorezero {s} [i-8] ptr mem)
+(MOVDstorezero {s} [i] ptr x:(MOVDstorezero {s} [i+8] ptr mem)) && x.Uses == 1 && setPos(v, x.Pos) && clobber(x) => (MOVQstorezero {s} [i] ptr mem)
+(MOVDstorezero {s} [i] ptr x:(MOVDstorezero {s} [i-8] ptr mem)) && x.Uses == 1 && setPos(v, x.Pos) && clobber(x) => (MOVQstorezero {s} [i-8] ptr mem)
 
 // strip off fractional word move
 (Move [s] dst src mem) && s%16 != 0 && s%16 <= 8 && s > 16 =>
diff --git a/src/cmd/compile/internal/ssa/_gen/S390X.rules b/src/cmd/compile/internal/ssa/_gen/S390X.rules
index a9d62c79ce..2a6d7e737c 100644
--- a/src/cmd/compile/internal/ssa/_gen/S390X.rules
+++ b/src/cmd/compile/internal/ssa/_gen/S390X.rules
@@ -1300,21 +1300,25 @@
   && p.Op != OpSB
   && x.Uses == 1
   && is20Bit(int64(i)-4)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STM2 [i-4] {s} p w0 w1 mem)
 (MOVWstore [i] {s} p w2 x:(STM2 [i-8] {s} p w0 w1 mem))
   && x.Uses == 1
   && is20Bit(int64(i)-8)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STM3 [i-8] {s} p w0 w1 w2 mem)
 (MOVWstore [i] {s} p w3 x:(STM3 [i-12] {s} p w0 w1 w2 mem))
   && x.Uses == 1
   && is20Bit(int64(i)-12)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STM4 [i-12] {s} p w0 w1 w2 w3 mem)
 (STM2 [i] {s} p w2 w3 x:(STM2 [i-8] {s} p w0 w1 mem))
   && x.Uses == 1
   && is20Bit(int64(i)-8)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STM4 [i-8] {s} p w0 w1 w2 w3 mem)
 // 64-bit
@@ -1322,21 +1326,25 @@
   && p.Op != OpSB
   && x.Uses == 1
   && is20Bit(int64(i)-8)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STMG2 [i-8] {s} p w0 w1 mem)
 (MOVDstore [i] {s} p w2 x:(STMG2 [i-16] {s} p w0 w1 mem))
   && x.Uses == 1
   && is20Bit(int64(i)-16)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STMG3 [i-16] {s} p w0 w1 w2 mem)
 (MOVDstore [i] {s} p w3 x:(STMG3 [i-24] {s} p w0 w1 w2 mem))
   && x.Uses == 1
   && is20Bit(int64(i)-24)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STMG4 [i-24] {s} p w0 w1 w2 w3 mem)
 (STMG2 [i] {s} p w2 w3 x:(STMG2 [i-16] {s} p w0 w1 mem))
   && x.Uses == 1
   && is20Bit(int64(i)-16)
+  && setPos(v, x.Pos)
   && clobber(x)
   => (STMG4 [i-16] {s} p w0 w1 w2 w3 mem)
 
diff --git a/src/cmd/compile/internal/ssa/memcombine.go b/src/cmd/compile/internal/ssa/memcombine.go
index 8e3db5a378..848b1e57a7 100644
--- a/src/cmd/compile/internal/ssa/memcombine.go
+++ b/src/cmd/compile/internal/ssa/memcombine.go
@@ -512,6 +512,8 @@ func combineStores(root *Value, n int64) bool {
 	}
 	// Before we sort, grab the memory arg the result should have.
 	mem := a[n-1].store.Args[2]
+	// Also grab position of first store (last in array = first in memory order).
+	pos := a[n-1].store.Pos
 
 	// Sort stores in increasing address order.
 	sort.Slice(a, func(i, j int) bool {
@@ -564,6 +566,7 @@ func combineStores(root *Value, n int64) bool {
 			v := a[i].store
 			if v == root {
 				v.Aux = cv.Type // widen store type
+				v.Pos = pos
 				v.SetArg(0, ptr)
 				v.SetArg(1, cv)
 				v.SetArg(2, mem)
@@ -632,6 +635,7 @@ func combineStores(root *Value, n int64) bool {
 			v := a[i].store
 			if v == root {
 				v.Aux = load.Type // widen store type
+				v.Pos = pos
 				v.SetArg(0, ptr)
 				v.SetArg(1, load)
 				v.SetArg(2, mem)
@@ -703,6 +707,7 @@ func combineStores(root *Value, n int64) bool {
 		v := a[i].store
 		if v == root {
 			v.Aux = sv.Type // widen store type
+			v.Pos = pos
 			v.SetArg(0, ptr)
 			v.SetArg(1, sv)
 			v.SetArg(2, mem)
diff --git a/src/cmd/compile/internal/ssa/rewrite.go b/src/cmd/compile/internal/ssa/rewrite.go
index eebedea68c..c5bd7cf3a9 100644
--- a/src/cmd/compile/internal/ssa/rewrite.go
+++ b/src/cmd/compile/internal/ssa/rewrite.go
@@ -2146,3 +2146,11 @@ func isARM64addcon(v int64) bool {
 	}
 	return v <= 0xFFF
 }
+
+// setPos sets the position of v to pos, then returns true.
+// Useful for setting the result of a rewrite's position to
+// something other than the default.
+func setPos(v *Value, pos src.XPos) bool {
+	v.Pos = pos
+	return true
+}
diff --git a/src/cmd/compile/internal/ssa/rewriteAMD64.go b/src/cmd/compile/internal/ssa/rewriteAMD64.go
index 5cf5425fdc..5332512f2a 100644
--- a/src/cmd/compile/internal/ssa/rewriteAMD64.go
+++ b/src/cmd/compile/internal/ssa/rewriteAMD64.go
@@ -12204,7 +12204,7 @@ func rewriteValueAMD64_OpAMD64MOVQstoreconst(v *Value) bool {
 		return true
 	}
 	// match: (MOVQstoreconst [c] {s} p1 x:(MOVQstoreconst [a] {s} p0 mem))
-	// cond: config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && clobber(x)
+	// cond: config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && setPos(v, x.Pos) && clobber(x)
 	// result: (MOVOstoreconst [makeValAndOff(0,a.Off())] {s} p0 mem)
 	for {
 		c := auxIntToValAndOff(v.AuxInt)
@@ -12220,7 +12220,7 @@ func rewriteValueAMD64_OpAMD64MOVQstoreconst(v *Value) bool {
 		}
 		mem := x.Args[1]
 		p0 := x.Args[0]
-		if !(config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && clobber(x)) {
+		if !(config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpAMD64MOVOstoreconst)
@@ -12230,7 +12230,7 @@ func rewriteValueAMD64_OpAMD64MOVQstoreconst(v *Value) bool {
 		return true
 	}
 	// match: (MOVQstoreconst [a] {s} p0 x:(MOVQstoreconst [c] {s} p1 mem))
-	// cond: config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && clobber(x)
+	// cond: config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && setPos(v, x.Pos) && clobber(x)
 	// result: (MOVOstoreconst [makeValAndOff(0,a.Off())] {s} p0 mem)
 	for {
 		a := auxIntToValAndOff(v.AuxInt)
@@ -12246,7 +12246,7 @@ func rewriteValueAMD64_OpAMD64MOVQstoreconst(v *Value) bool {
 		}
 		mem := x.Args[1]
 		p1 := x.Args[0]
-		if !(config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && clobber(x)) {
+		if !(config.useSSE && x.Uses == 1 && sequentialAddresses(p0, p1, int64(a.Off()+8-c.Off())) && a.Val() == 0 && c.Val() == 0 && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpAMD64MOVOstoreconst)
diff --git a/src/cmd/compile/internal/ssa/rewriteARM64.go b/src/cmd/compile/internal/ssa/rewriteARM64.go
index d7752d3876..f0a4425502 100644
--- a/src/cmd/compile/internal/ssa/rewriteARM64.go
+++ b/src/cmd/compile/internal/ssa/rewriteARM64.go
@@ -9867,7 +9867,7 @@ func rewriteValueARM64_OpARM64MOVDstorezero(v *Value) bool {
 	b := v.Block
 	config := b.Func.Config
 	// match: (MOVDstorezero {s} [i] ptr x:(MOVDstorezero {s} [i+8] ptr mem))
-	// cond: x.Uses == 1 && clobber(x)
+	// cond: x.Uses == 1 && setPos(v, x.Pos) && clobber(x)
 	// result: (MOVQstorezero {s} [i] ptr mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -9878,7 +9878,7 @@ func rewriteValueARM64_OpARM64MOVDstorezero(v *Value) bool {
 			break
 		}
 		mem := x.Args[1]
-		if ptr != x.Args[0] || !(x.Uses == 1 && clobber(x)) {
+		if ptr != x.Args[0] || !(x.Uses == 1 && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpARM64MOVQstorezero)
@@ -9888,7 +9888,7 @@ func rewriteValueARM64_OpARM64MOVDstorezero(v *Value) bool {
 		return true
 	}
 	// match: (MOVDstorezero {s} [i] ptr x:(MOVDstorezero {s} [i-8] ptr mem))
-	// cond: x.Uses == 1 && clobber(x)
+	// cond: x.Uses == 1 && setPos(v, x.Pos) && clobber(x)
 	// result: (MOVQstorezero {s} [i-8] ptr mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -9899,7 +9899,7 @@ func rewriteValueARM64_OpARM64MOVDstorezero(v *Value) bool {
 			break
 		}
 		mem := x.Args[1]
-		if ptr != x.Args[0] || !(x.Uses == 1 && clobber(x)) {
+		if ptr != x.Args[0] || !(x.Uses == 1 && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpARM64MOVQstorezero)
diff --git a/src/cmd/compile/internal/ssa/rewriteS390X.go b/src/cmd/compile/internal/ssa/rewriteS390X.go
index a3d621898f..c2342c944d 100644
--- a/src/cmd/compile/internal/ssa/rewriteS390X.go
+++ b/src/cmd/compile/internal/ssa/rewriteS390X.go
@@ -9060,7 +9060,7 @@ func rewriteValueS390X_OpS390XMOVDstore(v *Value) bool {
 		return true
 	}
 	// match: (MOVDstore [i] {s} p w1 x:(MOVDstore [i-8] {s} p w0 mem))
-	// cond: p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-8) && clobber(x)
+	// cond: p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-8) && setPos(v, x.Pos) && clobber(x)
 	// result: (STMG2 [i-8] {s} p w0 w1 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -9076,7 +9076,7 @@ func rewriteValueS390X_OpS390XMOVDstore(v *Value) bool {
 			break
 		}
 		w0 := x.Args[1]
-		if !(p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-8) && clobber(x)) {
+		if !(p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-8) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTMG2)
@@ -9086,7 +9086,7 @@ func rewriteValueS390X_OpS390XMOVDstore(v *Value) bool {
 		return true
 	}
 	// match: (MOVDstore [i] {s} p w2 x:(STMG2 [i-16] {s} p w0 w1 mem))
-	// cond: x.Uses == 1 && is20Bit(int64(i)-16) && clobber(x)
+	// cond: x.Uses == 1 && is20Bit(int64(i)-16) && setPos(v, x.Pos) && clobber(x)
 	// result: (STMG3 [i-16] {s} p w0 w1 w2 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -9103,7 +9103,7 @@ func rewriteValueS390X_OpS390XMOVDstore(v *Value) bool {
 		}
 		w0 := x.Args[1]
 		w1 := x.Args[2]
-		if !(x.Uses == 1 && is20Bit(int64(i)-16) && clobber(x)) {
+		if !(x.Uses == 1 && is20Bit(int64(i)-16) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTMG3)
@@ -9113,7 +9113,7 @@ func rewriteValueS390X_OpS390XMOVDstore(v *Value) bool {
 		return true
 	}
 	// match: (MOVDstore [i] {s} p w3 x:(STMG3 [i-24] {s} p w0 w1 w2 mem))
-	// cond: x.Uses == 1 && is20Bit(int64(i)-24) && clobber(x)
+	// cond: x.Uses == 1 && is20Bit(int64(i)-24) && setPos(v, x.Pos) && clobber(x)
 	// result: (STMG4 [i-24] {s} p w0 w1 w2 w3 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -9131,7 +9131,7 @@ func rewriteValueS390X_OpS390XMOVDstore(v *Value) bool {
 		w0 := x.Args[1]
 		w1 := x.Args[2]
 		w2 := x.Args[3]
-		if !(x.Uses == 1 && is20Bit(int64(i)-24) && clobber(x)) {
+		if !(x.Uses == 1 && is20Bit(int64(i)-24) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTMG4)
@@ -10595,7 +10595,7 @@ func rewriteValueS390X_OpS390XMOVWstore(v *Value) bool {
 		return true
 	}
 	// match: (MOVWstore [i] {s} p w1 x:(MOVWstore [i-4] {s} p w0 mem))
-	// cond: p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-4) && clobber(x)
+	// cond: p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-4) && setPos(v, x.Pos) && clobber(x)
 	// result: (STM2 [i-4] {s} p w0 w1 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -10611,7 +10611,7 @@ func rewriteValueS390X_OpS390XMOVWstore(v *Value) bool {
 			break
 		}
 		w0 := x.Args[1]
-		if !(p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-4) && clobber(x)) {
+		if !(p.Op != OpSB && x.Uses == 1 && is20Bit(int64(i)-4) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTM2)
@@ -10621,7 +10621,7 @@ func rewriteValueS390X_OpS390XMOVWstore(v *Value) bool {
 		return true
 	}
 	// match: (MOVWstore [i] {s} p w2 x:(STM2 [i-8] {s} p w0 w1 mem))
-	// cond: x.Uses == 1 && is20Bit(int64(i)-8) && clobber(x)
+	// cond: x.Uses == 1 && is20Bit(int64(i)-8) && setPos(v, x.Pos) && clobber(x)
 	// result: (STM3 [i-8] {s} p w0 w1 w2 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -10638,7 +10638,7 @@ func rewriteValueS390X_OpS390XMOVWstore(v *Value) bool {
 		}
 		w0 := x.Args[1]
 		w1 := x.Args[2]
-		if !(x.Uses == 1 && is20Bit(int64(i)-8) && clobber(x)) {
+		if !(x.Uses == 1 && is20Bit(int64(i)-8) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTM3)
@@ -10648,7 +10648,7 @@ func rewriteValueS390X_OpS390XMOVWstore(v *Value) bool {
 		return true
 	}
 	// match: (MOVWstore [i] {s} p w3 x:(STM3 [i-12] {s} p w0 w1 w2 mem))
-	// cond: x.Uses == 1 && is20Bit(int64(i)-12) && clobber(x)
+	// cond: x.Uses == 1 && is20Bit(int64(i)-12) && setPos(v, x.Pos) && clobber(x)
 	// result: (STM4 [i-12] {s} p w0 w1 w2 w3 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -10666,7 +10666,7 @@ func rewriteValueS390X_OpS390XMOVWstore(v *Value) bool {
 		w0 := x.Args[1]
 		w1 := x.Args[2]
 		w2 := x.Args[3]
-		if !(x.Uses == 1 && is20Bit(int64(i)-12) && clobber(x)) {
+		if !(x.Uses == 1 && is20Bit(int64(i)-12) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTM4)
@@ -13107,7 +13107,7 @@ func rewriteValueS390X_OpS390XSTM2(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
 	// match: (STM2 [i] {s} p w2 w3 x:(STM2 [i-8] {s} p w0 w1 mem))
-	// cond: x.Uses == 1 && is20Bit(int64(i)-8) && clobber(x)
+	// cond: x.Uses == 1 && is20Bit(int64(i)-8) && setPos(v, x.Pos) && clobber(x)
 	// result: (STM4 [i-8] {s} p w0 w1 w2 w3 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -13125,7 +13125,7 @@ func rewriteValueS390X_OpS390XSTM2(v *Value) bool {
 		}
 		w0 := x.Args[1]
 		w1 := x.Args[2]
-		if !(x.Uses == 1 && is20Bit(int64(i)-8) && clobber(x)) {
+		if !(x.Uses == 1 && is20Bit(int64(i)-8) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTM4)
@@ -13162,7 +13162,7 @@ func rewriteValueS390X_OpS390XSTMG2(v *Value) bool {
 	v_1 := v.Args[1]
 	v_0 := v.Args[0]
 	// match: (STMG2 [i] {s} p w2 w3 x:(STMG2 [i-16] {s} p w0 w1 mem))
-	// cond: x.Uses == 1 && is20Bit(int64(i)-16) && clobber(x)
+	// cond: x.Uses == 1 && is20Bit(int64(i)-16) && setPos(v, x.Pos) && clobber(x)
 	// result: (STMG4 [i-16] {s} p w0 w1 w2 w3 mem)
 	for {
 		i := auxIntToInt32(v.AuxInt)
@@ -13180,7 +13180,7 @@ func rewriteValueS390X_OpS390XSTMG2(v *Value) bool {
 		}
 		w0 := x.Args[1]
 		w1 := x.Args[2]
-		if !(x.Uses == 1 && is20Bit(int64(i)-16) && clobber(x)) {
+		if !(x.Uses == 1 && is20Bit(int64(i)-16) && setPos(v, x.Pos) && clobber(x)) {
 			break
 		}
 		v.reset(OpS390XSTMG4)
diff --git a/test/codegen/memcombine.go b/test/codegen/memcombine.go
index adad9c613d..1b8abc348a 100644
--- a/test/codegen/memcombine.go
+++ b/test/codegen/memcombine.go
@@ -748,16 +748,16 @@ func zero_byte_4(b1, b2 []byte) {
 
 func zero_byte_8(b []byte) {
 	_ = b[7]
-	b[0], b[1], b[2], b[3] = 0, 0, 0, 0
-	b[4], b[5], b[6], b[7] = 0, 0, 0, 0 // arm64:"MOVD\tZR",-"MOVB",-"MOVH",-"MOVW"
+	b[0], b[1], b[2], b[3] = 0, 0, 0, 0 // arm64:"MOVD\tZR",-"MOVB",-"MOVH",-"MOVW"
+	b[4], b[5], b[6], b[7] = 0, 0, 0, 0
 }
 
 func zero_byte_16(b []byte) {
 	_ = b[15]
-	b[0], b[1], b[2], b[3] = 0, 0, 0, 0
+	b[0], b[1], b[2], b[3] = 0, 0, 0, 0 // arm64:"STP",-"MOVB",-"MOVH",-"MOVW"
 	b[4], b[5], b[6], b[7] = 0, 0, 0, 0
 	b[8], b[9], b[10], b[11] = 0, 0, 0, 0
-	b[12], b[13], b[14], b[15] = 0, 0, 0, 0 // arm64:"STP",-"MOVB",-"MOVH",-"MOVW"
+	b[12], b[13], b[14], b[15] = 0, 0, 0, 0
 }
 
 func zero_byte_30(a *[30]byte) {
@@ -809,8 +809,8 @@ func zero_uint16_4(h1, h2 []uint16) {
 
 func zero_uint16_8(h []uint16) {
 	_ = h[7]
-	h[0], h[1], h[2], h[3] = 0, 0, 0, 0
-	h[4], h[5], h[6], h[7] = 0, 0, 0, 0 // arm64:"STP",-"MOVB",-"MOVH"
+	h[0], h[1], h[2], h[3] = 0, 0, 0, 0 // arm64:"STP",-"MOVB",-"MOVH"
+	h[4], h[5], h[6], h[7] = 0, 0, 0, 0
 }
 
 func zero_uint32_2(w1, w2 []uint32) {
@@ -858,3 +858,27 @@ func loadstore2(p, q *S1) {
 	// arm64:"MOVW",-"MOVH"
 	q.a, q.b = a, b
 }
+
+func wideStore(p *[8]uint64) {
+	if p == nil {
+		return
+	}
+
+	// amd64:"MOVUPS",-"MOVQ"
+	// arm64:"STP",-"MOVD"
+	p[0] = 0
+	// amd64:-"MOVUPS",-"MOVQ"
+	// arm64:-"STP",-"MOVD"
+	p[1] = 0
+}
+
+func wideStore2(p *[8]uint64, x, y uint64) {
+	if p == nil {
+		return
+	}
+
+	// s390x:"STMG"
+	p[0] = x
+	// s390x:-"STMG",-"MOVD"
+	p[1] = y
+}