cmd/compile: always zero the temporary in mapKeyTemp

As we are taking its address, always zero it. In many cases the
temporary will be optimized out. But in case it does not (e.g. -N,
-race), this ensures it has the right liveness information.

May fix the noopt builder.

Change-Id: I3d5d617c276d2a1a1aaebff813b4cd60bc691592
Reviewed-on: https://go-review.googlesource.com/c/go/+/309771
Trust: Cherry Zhang <cherryyz@google.com>
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>

diff --git a/src/cmd/compile/internal/walk/order.go b/src/cmd/compile/internal/walk/order.go
index 8b306326650081264779c10fd4acc7464cab56de..42d9d589713e9aeabe42e25036cd55db8e6cabeb 100644 (file)
--- a/src/cmd/compile/internal/walk/order.go
+++ b/src/cmd/compile/internal/walk/order.go
@@ -306,8 +306,7 @@ func (o *orderState) mapKeyTemp(t *types.Type, n ir.Node) ir.Node {
                if kt.Align < nt.Align {
                        base.Fatalf("mapKeyTemp: key type is not sufficiently aligned, kt=%v nt=%v", kt, nt)
                }
-               clear := base.Flag.Cfg.Instrumenting // clear tmp if instrumenting, as it may be live at an inserted race call
-               tmp := o.newTemp(kt, clear)
+               tmp := o.newTemp(kt, true)
                // *(*nt)(&tmp) = n
                var e ir.Node = typecheck.NodAddr(tmp)
                e = ir.NewConvExpr(n.Pos(), ir.OCONVNOP, nt.PtrTo(), e)