From: Keith Randall <khr@golang.org>
Date: Fri, 20 Jan 2023 18:36:19 +0000 (-0800)
Subject: cmd/compile: ensure register args come before on-stack args in schedule
X-Git-Tag: go1.21rc1~1849
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=b08d5ee5e9c700a1267f0b883702766a19d89b2d;p=gostls13.git

cmd/compile: ensure register args come before on-stack args in schedule

The register allocator doesn't like OpArg coming in between other
OpIntArg operations, as it doesn't put the spills in the right place
in that situation.

This is just a bug in the new scheduler, I didn't copy over the
proper score from the old scheduler correctly.

Change-Id: I3b4ee1754982fb360e99c5864b19e7408d60b5bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/462858
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Keith Randall <khr@google.com>
Auto-Submit: Keith Randall <khr@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
---

diff --git a/src/cmd/compile/internal/ssa/schedule.go b/src/cmd/compile/internal/ssa/schedule.go
index a69e406df2..246376c767 100644
--- a/src/cmd/compile/internal/ssa/schedule.go
+++ b/src/cmd/compile/internal/ssa/schedule.go
@@ -135,7 +135,7 @@ func schedule(f *Func) {
 				if b != f.Entry {
 					f.Fatalf("%s appeared outside of entry block, b=%s", v.Op, b.String())
 				}
-				score[v.ID] = ScoreArg
+				score[v.ID] = ScorePhi
 			case v.Op == OpArg:
 				// We want all the args as early as possible, for better debugging.
 				score[v.ID] = ScoreArg