diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index 0c77a6dee8..994e880bc6 100644
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -404,6 +404,9 @@
 // Load of store of same address, with compatibly typed value and same size
 (Load <t1> p1 (Store [w] p2 x _)) && isSamePtr(p1,p2) && t1.Compare(x.Type)==CMPeq && w == t1.Size() -> x
 
+// Collapse OffPtr
+(OffPtr (OffPtr p [b]) [a]) -> (OffPtr p [a+b])
+
 
 // indexing operations
 // Note: bounds check has already been done
diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 1ed5fa9555..79dcf9a716 100644
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -206,6 +206,8 @@ func rewriteValuegeneric(v *Value, config *Config) bool {
 		return rewriteValuegeneric_OpNeqPtr(v, config)
 	case OpNeqSlice:
 		return rewriteValuegeneric_OpNeqSlice(v, config)
+	case OpOffPtr:
+		return rewriteValuegeneric_OpOffPtr(v, config)
 	case OpOr16:
 		return rewriteValuegeneric_OpOr16(v, config)
 	case OpOr32:
@@ -4821,6 +4823,26 @@ func rewriteValuegeneric_OpNeqSlice(v *Value, config *Config) bool {
 	}
 	return false
 }
+func rewriteValuegeneric_OpOffPtr(v *Value, config *Config) bool {
+	b := v.Block
+	_ = b
+	// match: (OffPtr (OffPtr p [b]) [a])
+	// cond:
+	// result: (OffPtr p [a+b])
+	for {
+		if v.Args[0].Op != OpOffPtr {
+			break
+		}
+		p := v.Args[0].Args[0]
+		b := v.Args[0].AuxInt
+		a := v.AuxInt
+		v.reset(OpOffPtr)
+		v.AddArg(p)
+		v.AuxInt = a + b
+		return true
+	}
+	return false
+}
 func rewriteValuegeneric_OpOr16(v *Value, config *Config) bool {
 	b := v.Block
 	_ = b