[dev.ssa] cmd/compile: fix spill sizes
In code that does:
var x, z int32
var y int64
z = phi(x, int32(y))
We silently drop the int32 cast because truncation is a no-op.
The phi operation needs to make sure it uses the size of the
phi, not the size of its arguments, when generating spills.
Change-Id: I1f7baf44f019256977a46fdd3dad1972be209042
Reviewed-on: https://go-review.googlesource.com/18390
Reviewed-by: David Chase <drchase@google.com>
diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index 55ab8ce2..eee3051 100644
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -4536,6 +4536,9 @@
// where v should be spilled.
func autoVar(v *ssa.Value) (*Node, int64) {
loc := v.Block.Func.RegAlloc[v.ID].(ssa.LocalSlot)
+ if v.Type.Size() > loc.Type.Size() {
+ v.Fatalf("spill/restore type %s doesn't fit in slot type %s", v.Type, loc.Type)
+ }
return loc.N.(*Node), loc.Off
}
