tree 62290565a3ad3386eff9aeaa0a30d615a044bda7
parent c25dd3f8325a5022a2573c71afd810f3fb604b08
author Keith Randall <khr@golang.org> 1596898684 -0700
committer Dmitri Shuralyov <dmitshur@golang.org> 1601938895 +0000

[release-branch.go1.15] cmd/compile: fix live variable computation for deferreturn

Taking the live variable set from the last return point is problematic.
See #40629 for details, but there may not be a return point, or it may
be before the final defer.

Additionally, keeping track of the last call as a *Value doesn't quite
work. If it is dead-code eliminated, the storage for the Value is reused
for some other random instruction. Its live variable information,
if it is available at all, is wrong.

Instead, just mark all the open-defer argument slots as live
throughout the function. (They are already zero-initialized.)

Fixes #40742

Change-Id: Ie456c7db3082d0de57eaa5234a0f32525a1cce13
Reviewed-on: https://go-review.googlesource.com/c/go/+/247522
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dan Scales <danscales@google.com>
(cherry picked from commit 32a84c99e136ed5af0686dbedd31fd7dff40fb38)
Reviewed-on: https://go-review.googlesource.com/c/go/+/248621
Trust: Dmitri Shuralyov <dmitshur@golang.org>