From: Keith Randall <khr@golang.org>
Date: Sun, 24 Jul 2022 16:48:56 +0000 (-0700)
Subject: cmd/compile: fix blank label code
X-Git-Tag: go1.19~3^2~16
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=24dc27a3c0;p=gostls13.git

cmd/compile: fix blank label code

When checkEnabled is forced true, the 52278 test fails. Be a bit
more careful about processing blank labels.

Update #52278

Change-Id: I48aa89e2c9e3715d8efe599bc4363b5b5879d8a2
Reviewed-on: https://go-review.googlesource.com/c/go/+/419318
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: David Chase <drchase@google.com>
---

diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
index a7778d37fb..2ee027092e 100644
--- a/src/cmd/compile/internal/ssagen/ssa.go
+++ b/src/cmd/compile/internal/ssagen/ssa.go
@@ -1496,6 +1496,10 @@ func (s *state) stmt(n ir.Node) {
 	case ir.OLABEL:
 		n := n.(*ir.LabelStmt)
 		sym := n.Label
+		if sym.IsBlank() {
+			// Nothing to do because the label isn't targetable. See issue 52278.
+			break
+		}
 		lab := s.label(sym)
 
 		// The label might already have a target block via a goto.
diff --git a/test/fixedbugs/issue52278.go b/test/fixedbugs/issue52278.go
index 56169e6871..147b653037 100644
--- a/test/fixedbugs/issue52278.go
+++ b/test/fixedbugs/issue52278.go
@@ -1,4 +1,4 @@
-// compile
+// compile -d=ssa/check/on
 
 // Copyright 2022 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style