From 315dbd10c90db3b41af2c975a5fbfa2ec7615c1b Mon Sep 17 00:00:00 2001
From: Keith Randall <khr@golang.org>
Date: Sun, 19 Sep 2021 09:23:37 -0700
Subject: cmd/compile: fold double negate on arm64

Fixes #48467

Change-Id: I52305dbf561ee3eee6c1f053e555a3a6ec1ab892
Reviewed-on: https://go-review.googlesource.com/c/go/+/350910
Trust: Keith Randall <khr@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
---
 test/codegen/bits.go | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'test/codegen')

diff --git a/test/codegen/bits.go b/test/codegen/bits.go
index 8117a62307..8e973d5726 100644
--- a/test/codegen/bits.go
+++ b/test/codegen/bits.go
@@ -6,6 +6,8 @@
 
 package codegen
 
+import "math/bits"
+
 /************************************
  * 64-bit instructions
  ************************************/
@@ -355,3 +357,9 @@ func issue44228b(a []int32, i int) bool {
 	// amd64: "BTL", -"SHL"
 	return a[i>>5]&(1<<(i&31)) != 0
 }
+
+func issue48467(x, y uint64) uint64 {
+	// arm64: -"NEG"
+	d, borrow := bits.Sub64(x, y, 0)
+	return x - d&(-borrow)
+}
-- 
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