[dev.ssa] cmd/compile/internal/gc: handle _ label correctly

An empty label statement can just be ignored, as it cannot be the target of any gotos. Tests are already in test/fixedbugs/issue7538*.go Fixes #11589 Fixes #11593 Change-Id: Iadcd639e7200ce16aa40fd7fa3eaf82522513e82 Reviewed-on: https://go-review.googlesource.com/12093 Reviewed-by: Daniel Morsing <[email protected]> Reviewed-by: Brad Fitzpatrick <[email protected]>
golang · Jul 12, 2015 · 7e4c06d · 7e4c06d
1 parent 4c521ac
commit 7e4c06d
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
@@ -316,6 +316,11 @@ func (s *state) stmt(n *Node) {
 		s.assign(OAS, n.Left.Name.Heapaddr, palloc)
 
 	case OLABEL, OGOTO:
+		if n.Op == OLABEL && isblanksym(n.Left.Sym) {
+			// Empty identifier is valid but useless.
+			// See issues 11589, 11593.
+			return
+		}
 		// get block at label, or make one
 		t := s.labels[n.Left.Sym.Name]
 		if t == nil {