tree 149151d71f957eab398356d0ee16b3eb15aac425
parent 8de2f604c0b225aa41cb1b4e2ab97e3512a51445
author Keith Randall <khr@google.com> 1518554035 -0800
committer Keith Randall <khr@golang.org> 1518566616 +0000

cmd/compile: fix constant folding of right shifts

The sub-word shifts need to sign-extend before shifting, to avoid
bringing in data from higher in the argument.

Fixes #23812

Change-Id: I0a95a0b49c48f3b40b85765bb4a9bb492be0cd73
Reviewed-on: https://go-review.googlesource.com/93716
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>