mirror of
https://github.com/golang/go
synced 2024-11-22 15:34:53 -07:00
c8057d8569
if q != nil {
p = &q.f
}
Which gets rewritten to a conditional move:
tmp := &q.f
p = Select q!=nil, tmp, p
Unfortunately, we can't compute &q.f before we've checked if q is nil,
because if it is nil, &q.f is an invalid pointer (if f's offset is
nonzero but small).
Normally this is not a problem because the tmp variable above
immediately dies, and is thus not live across any safepoint. However,
if later there is another &q.f computation, those two computations are
CSEd, causing tmp to be used at both use points. That will extend
tmp's lifetime, possibly across a call.
Fixes #56990
Change-Id: I3ea31be93feae04fbe3304cb11323194c5df3879
Reviewed-on: https://go-review.googlesource.com/c/go/+/454155
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
2 lines
5 B
Plaintext
2 lines
5 B
Plaintext
PASS
|