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eric fang e0ceba8139 cmd/compile: enhance tighten pass for memory values
[This is a roll-forward of CL 458755, which was reverted due to make.bash
being broken on GOAMD64=v3. But it turned out that the problem was caused
by wrong bswap/load rewrite rules, and it was fixed in CL 492616.]

This CL enhances the tighten pass. Previously if a value has memory arg,
then the tighten pass won't move it, actually if the memory state is
consistent among definition and use block, we can move the value. This
CL optimizes this case. This is useful for the following situation:
b1:
  x = load(...mem)
  if(...) goto b2 else b3
b2:
  use(x)
b3:
  some_op_not_use_x

For the micro-benchmark mentioned in #56620, the performance improvement
is about 15%.
There's no noticeable performance change in the go1 benchmark.

Fixes #56620

Change-Id: I36ea68bed384986cd3ae81cb9e6efe84bb213adc
Reviewed-on: https://go-review.googlesource.com/c/go/+/492895
Reviewed-by: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Eric Fang <eric.fang@arm.com>
2023-05-16 01:01:38 +00:00
.github doc: normalize proposal-process links 2023-03-29 22:00:27 +00:00
api net/http: let ErrNotSupported match errors.ErrUnsupported 2023-05-10 20:13:04 +00:00
doc doc: fix typo in Go 1.21 release notes 2023-04-24 18:13:34 +00:00
lib/time lib/time: update to 2023c/2023c 2023-05-03 20:14:11 +00:00
misc misc: remove misc/arm/a script 2023-05-15 15:42:24 +00:00
src cmd/compile: enhance tighten pass for memory values 2023-05-16 01:01:38 +00:00
test cmd/compile: enhance tighten pass for memory values 2023-05-16 01:01:38 +00:00
.gitattributes all: treat all files as binary, but check in .bat with CRLF 2020-06-08 15:31:43 +00:00
.gitignore cmd/dist: refactor generated cgo-support logic 2023-04-20 17:26:46 +00:00
codereview.cfg codereview.cfg: add codereview.cfg for master branch 2021-02-19 18:44:53 +00:00
CONTRIBUTING.md doc: normalize proposal-process links 2023-03-29 22:00:27 +00:00
go.env cmd/go: introduce GOROOT/go.env and move proxy/sumdb config there 2023-01-17 23:10:39 +00:00
LICENSE doc: revert copyright date to 2009 2016-06-01 22:40:04 +00:00
PATENTS LICENSE: separate, change PATENTS text 2010-12-06 16:31:59 -05:00
README.md README: update from CC-BY-3.0 to CC-BY-4.0 2022-11-02 20:14:56 +00:00
SECURITY.md SECURITY.md: replace golang.org with go.dev 2022-04-26 19:59:47 +00:00

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