cmd/compile: use BMI1 instructions for GOAMD64=v3 and higher

BMI1 includes four instructions (ANDN, BLSI, BLSMSK, BLSR) that are
easy to peephole optimize, and which GCC always seems to favor using
when available and applicable.

Updates #45453.

Change-Id: I0274184057058f5c579e5bc3ea9c414396d3cf46
Reviewed-on: https://go-review.googlesource.com/c/go/+/351130
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
Trust: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 47 insertions, 0 deletions

diff --git a/test/codegen/bmi.go b/test/codegen/bmi.go
new file mode 100644
index 0000000000..0c25e0b796
--- /dev/null
+++ b/test/codegen/bmi.go
@@ -0,0 +1,47 @@
+// asmcheck
+
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package codegen
+
+func andn64(x, y int64) int64 {
+	// amd64/v3:"ANDNQ"
+	return x &^ y
+}
+
+func andn32(x, y int32) int32 {
+	// amd64/v3:"ANDNL"
+	return x &^ y
+}
+
+func blsi64(x int64) int64 {
+	// amd64/v3:"BLSIQ"
+	return x & -x
+}
+
+func blsi32(x int32) int32 {
+	// amd64/v3:"BLSIL"
+	return x & -x
+}
+
+func blsmsk64(x int64) int64 {
+	// amd64/v3:"BLSMSKQ"
+	return x ^ (x - 1)
+}
+
+func blsmsk32(x int32) int32 {
+	// amd64/v3:"BLSMSKL"
+	return x ^ (x - 1)
+}
+
+func blsr64(x int64) int64 {
+	// amd64/v3:"BLSRQ"
+	return x & (x - 1)
+}
+
+func blsr32(x int32) int32 {
+	// amd64/v3:"BLSRL"
+	return x & (x - 1)
+}