From: Keith Randall <khr@golang.org>
Date: Fri, 12 Jun 2015 23:24:33 +0000 (-0700)
Subject: [dev.ssa] cmd/compile/internal/gc: Small fixes
X-Git-Tag: go1.7beta1~1623^2^2~443
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=0ad9c8c720324b6c4e483ac7fe0e20f36274e2eb;p=gostls13.git

[dev.ssa] cmd/compile/internal/gc: Small fixes

Allow labels to be unreachable via fallthrough from above.
Implement OCONVNOP.

Change-Id: I6869993cad8a27ad134dd637de89a40117daf47b
Reviewed-on: https://go-review.googlesource.com/11001
Reviewed-by: Daniel Morsing <daniel.morsing@gmail.com>
---

diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 131e97ff48..ebb7f44a18 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -217,8 +217,9 @@ func (s *state) stmt(n *Node) {
 			s.labels[n.Left.Sym.Name] = t
 		}
 		// go to that label (we pretend "label:" is preceded by "goto label")
-		b := s.endBlock()
-		addEdge(b, t)
+		if b := s.endBlock(); b != nil {
+			addEdge(b, t)
+		}
 
 		if n.Op == OLABEL {
 			// next we work on the label's target block
@@ -358,6 +359,9 @@ func (s *state) expr(n *Node) *ssa.Value {
 			log.Fatalf("unhandled OLITERAL %v", n.Val().Ctype())
 			return nil
 		}
+	case OCONVNOP:
+		x := s.expr(n.Left)
+		return s.newValue1(ssa.OpConvNop, n.Type, nil, x)
 
 		// binary ops
 	case OLT: