[dev.ssa] cmd/compile: implement control flow handling

Add label and goto checks and improve test coverage.

Implement OSWITCH and OSELECT.

Implement OBREAK and OCONTINUE.

Allow generation of code in dead blocks.

Change-Id: Ibebb7c98b4b2344f46d38db7c9dce058c56beaac
Reviewed-on: https://go-review.googlesource.com/12445
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/test/label.go b/test/label.go
index a1811c2d68..c3c0c27edd 100644
--- a/test/label.go
+++ b/test/label.go
@@ -58,4 +58,8 @@ L10:
 	default:
 		break L10
 	}
+
+	goto L10
+
+	goto go2 // ERROR "label go2 not defined"
 }