[release-branch.go1.18] cmd/compile: fix If lowering on ARM64
On ARM64, an If block is lowered to (NZ cond yes no). This is
incorrect because cond is a boolean value and therefore only the
last byte is meaningful (same as AMD64, see ARM64Ops.go). But here
we are comparing a full register width with 0. Correct it by
comparing only the last bit.
For #52788.
Fixes #53397.
Change-Id: I2cacf9f3d2f45e149c361a290f511b2d4ed845c4
Reviewed-on: https://go-review.googlesource.com/c/go/+/405114
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-on: https://go-review.googlesource.com/c/go/+/421457 Reviewed-by: Dmitri Shuralyov <dmitshur@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>