diff --git a/src/cmd/compile/internal/ssa/gen/S390XOps.go b/src/cmd/compile/internal/ssa/gen/S390XOps.go
index 283a0fa6b557c..65460bf6f711f 100644
--- a/src/cmd/compile/internal/ssa/gen/S390XOps.go
+++ b/src/cmd/compile/internal/ssa/gen/S390XOps.go
@@ -630,6 +630,7 @@ func init() {
 			asm:            "STMG",
 			faultOnNilArg0: true,
 			symEffect:      "Write",
+			clobberFlags:   true, // TODO(mundaym): currently uses AGFI to handle large offsets
 		},
 		{
 			name:           "STMG3",
@@ -640,6 +641,7 @@ func init() {
 			asm:            "STMG",
 			faultOnNilArg0: true,
 			symEffect:      "Write",
+			clobberFlags:   true, // TODO(mundaym): currently uses AGFI to handle large offsets
 		},
 		{
 			name:      "STMG4",
@@ -657,6 +659,7 @@ func init() {
 			asm:            "STMG",
 			faultOnNilArg0: true,
 			symEffect:      "Write",
+			clobberFlags:   true, // TODO(mundaym): currently uses AGFI to handle large offsets
 		},
 		{
 			name:           "STM2",
@@ -667,6 +670,7 @@ func init() {
 			asm:            "STMY",
 			faultOnNilArg0: true,
 			symEffect:      "Write",
+			clobberFlags:   true, // TODO(mundaym): currently uses AGFI to handle large offsets
 		},
 		{
 			name:           "STM3",
@@ -677,6 +681,7 @@ func init() {
 			asm:            "STMY",
 			faultOnNilArg0: true,
 			symEffect:      "Write",
+			clobberFlags:   true, // TODO(mundaym): currently uses AGFI to handle large offsets
 		},
 		{
 			name:      "STM4",
@@ -694,6 +699,7 @@ func init() {
 			asm:            "STMY",
 			faultOnNilArg0: true,
 			symEffect:      "Write",
+			clobberFlags:   true, // TODO(mundaym): currently uses AGFI to handle large offsets
 		},
 
 		// large move
diff --git a/src/cmd/compile/internal/ssa/opGen.go b/src/cmd/compile/internal/ssa/opGen.go
index 46ca7936dc7fb..bf48bff8f127a 100644
--- a/src/cmd/compile/internal/ssa/opGen.go
+++ b/src/cmd/compile/internal/ssa/opGen.go
@@ -30110,6 +30110,7 @@ var opcodeTable = [...]opInfo{
 		name:           "STMG2",
 		auxType:        auxSymOff,
 		argLen:         4,
+		clobberFlags:   true,
 		faultOnNilArg0: true,
 		symEffect:      SymWrite,
 		asm:            s390x.ASTMG,
@@ -30125,6 +30126,7 @@ var opcodeTable = [...]opInfo{
 		name:           "STMG3",
 		auxType:        auxSymOff,
 		argLen:         5,
+		clobberFlags:   true,
 		faultOnNilArg0: true,
 		symEffect:      SymWrite,
 		asm:            s390x.ASTMG,
@@ -30141,6 +30143,7 @@ var opcodeTable = [...]opInfo{
 		name:           "STMG4",
 		auxType:        auxSymOff,
 		argLen:         6,
+		clobberFlags:   true,
 		faultOnNilArg0: true,
 		symEffect:      SymWrite,
 		asm:            s390x.ASTMG,
@@ -30158,6 +30161,7 @@ var opcodeTable = [...]opInfo{
 		name:           "STM2",
 		auxType:        auxSymOff,
 		argLen:         4,
+		clobberFlags:   true,
 		faultOnNilArg0: true,
 		symEffect:      SymWrite,
 		asm:            s390x.ASTMY,
@@ -30173,6 +30177,7 @@ var opcodeTable = [...]opInfo{
 		name:           "STM3",
 		auxType:        auxSymOff,
 		argLen:         5,
+		clobberFlags:   true,
 		faultOnNilArg0: true,
 		symEffect:      SymWrite,
 		asm:            s390x.ASTMY,
@@ -30189,6 +30194,7 @@ var opcodeTable = [...]opInfo{
 		name:           "STM4",
 		auxType:        auxSymOff,
 		argLen:         6,
+		clobberFlags:   true,
 		faultOnNilArg0: true,
 		symEffect:      SymWrite,
 		asm:            s390x.ASTMY,