From 33a9f01729cb88b80f915ae6d2ae9779106b9f0c Mon Sep 17 00:00:00 2001
From: Alberto Donizetti <alb.donizetti@gmail.com>
Date: Fri, 3 Nov 2017 11:11:27 +0100
Subject: [PATCH] =?utf8?q?cmd/compile:=20add=20mul=20by=20=C2=B12=E2=81=BF?=
 =?utf8?q?=20code-generation=20tests=20for=20arm/arm64?=
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This change adds code generation tests for multiplication by ±2ⁿ for
arm and arm64, in preparation for a future CL which will remove the
relevant architecture-specific SSA rules (the reduction is already
performed by rules in generic.rules added in CL 36323).

Change-Id: Iebdd5c3bb2fc632c85888569ff0c49f78569a862
Reviewed-on: https://go-review.googlesource.com/75752
Reviewed-by: Cherry Zhang <cherryyz@google.com>
---
 src/cmd/compile/internal/gc/asm_test.go | 40 +++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/src/cmd/compile/internal/gc/asm_test.go b/src/cmd/compile/internal/gc/asm_test.go
index 57853001fd..78c6c5e2b7 100644
--- a/src/cmd/compile/internal/gc/asm_test.go
+++ b/src/cmd/compile/internal/gc/asm_test.go
@@ -1816,6 +1816,26 @@ var linuxS390XTests = []*asmTest{
 }
 
 var linuxARMTests = []*asmTest{
+	// multiplication by powers of two
+	{
+		fn: `
+		func $(n int) int {
+			return 16*n
+		}
+		`,
+		pos: []string{"\tSLL\t[$]4"},
+		neg: []string{"\tMUL\t"},
+	},
+	{
+		fn: `
+		func $(n int) int {
+			return -32*n
+		}
+		`,
+		pos: []string{"\tSLL\t[$]5"},
+		neg: []string{"\tMUL\t"},
+	},
+
 	{
 		fn: `
 		func f0(x uint32) uint32 {
@@ -1943,6 +1963,26 @@ var linuxARMTests = []*asmTest{
 }
 
 var linuxARM64Tests = []*asmTest{
+	// multiplication by powers of two
+	{
+		fn: `
+		func $(n int) int {
+			return 64*n
+		}
+		`,
+		pos: []string{"\tLSL\t[$]6"},
+		neg: []string{"\tMUL\t"},
+	},
+	{
+		fn: `
+		func $(n int) int {
+			return -128*n
+		}
+		`,
+		pos: []string{"\tLSL\t[$]7"},
+		neg: []string{"\tMUL\t"},
+	},
+
 	{
 		fn: `
 		func f0(x uint64) uint64 {
-- 
2.48.1