tree b118456372efccf40abe1ed28d4ffc930c3b42d4
parent d1882c986673b5bd5fb6775548990d4e11917c1e
author Keith Randall <khr@google.com> 1544573577 -0800
committer Keith Randall <khr@golang.org> 1544649195 +0000

cmd/compile: don't combine load+op if the op has SymAddr arguments

By combining the load+op, we may force the op to happen earlier in
the store chain. That might force the SymAddr operation earlier, and
in particular earlier than its corresponding VarDef. That leads to
an invalid schedule, so avoid that.

This is kind of a hack to work around the issue presented. I think
the underlying problem, that LEAQ is not directly ordered with respect
to its vardef, is the real problem. The benefit of this CL is that
it fixes the immediate issue, is small, and obviously won't break
anything. A real fix for this issue is much more invasive.

The go binary is unchanged in size.
This situation just doesn't occur very often.

Fixes #28445

Change-Id: I13a765e13f075d5b6808a355ef3c43cdd7cd47b6
Reviewed-on: https://go-review.googlesource.com/c/153641
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>