diff --git a/src/cmd/compile/internal/ssa/writebarrier.go b/src/cmd/compile/internal/ssa/writebarrier.go
index 419d91d0d36..d7510965f6b 100644
--- a/src/cmd/compile/internal/ssa/writebarrier.go
+++ b/src/cmd/compile/internal/ssa/writebarrier.go
@@ -552,6 +552,9 @@ func IsStackAddr(v *Value) bool {
 
 // IsGlobalAddr reports whether v is known to be an address of a global (or nil).
 func IsGlobalAddr(v *Value) bool {
+	for v.Op == OpOffPtr || v.Op == OpAddPtr || v.Op == OpPtrIndex || v.Op == OpCopy {
+		v = v.Args[0]
+	}
 	if v.Op == OpAddr && v.Args[0].Op == OpSB {
 		return true // address of a global
 	}
diff --git a/test/writebarrier.go b/test/writebarrier.go
index dbf0b6dde28..1b30fa509e5 100644
--- a/test/writebarrier.go
+++ b/test/writebarrier.go
@@ -289,3 +289,17 @@ func f27(p *int) []interface{} {
 		p,           // ERROR "write barrier"
 	}
 }
+
+var g28 [256]uint64
+
+func f28() []interface{} {
+	return []interface{}{
+		false,      // no write barrier
+		true,       // no write barrier
+		0,          // no write barrier
+		1,          // no write barrier
+		uint8(127), // no write barrier
+		int8(-4),   // no write barrier
+		&g28[5],    // no write barrier
+	}
+}