[dev.ssa] cmd/compile: implement OSTRUCTLIT and OARRAYLIT
The frontend rewrites most literals, so we see only zero
ones during SSA construction. We can implement those
using the existing zeroing behavior.
Change-Id: I390ad1be0a4b6729baf0c8936c7610aae2aef049
Reviewed-on: https://go-review.googlesource.com/14754
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 186c1a2..fb7e0c5 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -574,7 +574,16 @@
}
var r *ssa.Value
if n.Right != nil {
- r = s.expr(n.Right)
+ if n.Right.Op == OSTRUCTLIT || n.Right.Op == OARRAYLIT {
+ // All literals with nonzero fields have already been
+ // rewritten during walk. Any that remain are just T{}
+ // or equivalents. Leave r = nil to get zeroing behavior.
+ if !iszero(n.Right) {
+ Fatalf("literal with nonzero value in SSA: %v", n.Right)
+ }
+ } else {
+ r = s.expr(n.Right)
+ }
}
if n.Right != nil && n.Right.Op == OAPPEND {
// Yuck! The frontend gets rid of the write barrier, but we need it!
