cmd/compile: temporarily disable inplace append special case

Fixes #15246
Re-opens #14969

Change-Id: Ic0b41c5aa42bbb229a0d62b7f3e5888c6b29293d
Reviewed-on: https://go-review.googlesource.com/21891
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go
index beb68b0385f469cc4edd41aeb7379ed64f9a9da8..fdd14953e6bd0a1ea12a140dd72d760f910ad2b4 100644 (file)
--- a/src/cmd/compile/internal/gc/ssa.go
+++ b/src/cmd/compile/internal/gc/ssa.go
@@ -699,7 +699,8 @@ func (s *state) stmt(n *Node) {
                                // If the slice can be SSA'd, it'll be on the stack,
                                // so there will be no write barriers,
                                // so there's no need to attempt to prevent them.
-                               if samesafeexpr(n.Left, rhs.List.First()) && !s.canSSA(n.Left) {
+                               const doInPlaceAppend = false // issue 15246
+                               if doInPlaceAppend && samesafeexpr(n.Left, rhs.List.First()) && !s.canSSA(n.Left) {
                                        s.append(rhs, true)
                                        return
                                }