cmd/compile: randomize value order in block for testing

A little bit of compiler stress testing. Randomize the order
of the values in a block before every phase. This randomization
makes sure that we're not implicitly depending on that order.

Currently the random seed is a hash of the function name.
It provides determinism, but sacrifices some coverage.
Other arrangements are possible (env var, ...) but require
more setup.

Fixes #20178

Change-Id: Idae792a23264bd9a3507db6ba49b6d591a608e83
Reviewed-on: https://go-review.googlesource.com/c/33909
Reviewed-by: Cherry Zhang <cherryyz@google.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/test/run.go b/test/run.go
index 39647d7252..e7976657de 100644
--- a/test/run.go
+++ b/test/run.go
@@ -559,6 +559,19 @@ func (t *test) run() {
 		}
 		args = args[1:]
 	}
+	if action == "errorcheck" {
+		found := false
+		for i, f := range flags {
+			if strings.HasPrefix(f, "-d=") {
+				flags[i] = f + ",ssa/check/on"
+				found = true
+				break
+			}
+		}
+		if !found {
+			flags = append(flags, "-d=ssa/check/on")
+		}
+	}
 
 	t.makeTempDir()
 	if !*keep {