Commit9db29c2

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[release-branch.go1.1] cmd/6g, cmd/8g: prevent constant propagation of non-constant LEA.

««« CL 10785043 / cf792c00f410cmd/6g, cmd/8g: prevent constant propagation of non-constant LEA.Fixes#5809.R=golang-dev, dave, rsc, nigeltaoCC=golang-devhttps://golang.org/cl/10785043»»»Update#5928R=golang-dev, daveCC=golang-devhttps://golang.org/cl/11515045

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Original file line number	Diff line number	Diff line change
`@@ -152,6 +152,7 @@ peep(void)`
`152`	`152`	`caseALEAQ:`
`153`	`153`	`if(regtyp(&p->to))`
`154`	`154`	`if(p->from.sym!=S)`
	`155`	`+if(p->from.index==D_NONE\|\|p->from.index==D_CONST)`
`155`	`156`	`conprop(r);`
`156`	`157`	`break;`
`157`	`158`

Lines changed: 1 addition & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -145,6 +145,7 @@ peep(void)`
`145`	`145`	`caseALEAL:`
`146`	`146`	`if(regtyp(&p->to))`
`147`	`147`	`if(p->from.sym!=S)`
	`148`	`+if(p->from.index==D_NONE\|\|p->from.index==D_CONST)`
`148`	`149`	`conprop(r);`
`149`	`150`	`break;`
`150`	`151`

Lines changed: 27 additions & 0 deletions

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`@@ -0,0 +1,27 @@`
	`1`	`+// run`
	`2`	`+`
	`3`	`+// Copyright 2013 The Go Authors. All rights reserved.`
	`4`	`+// Use of this source code is governed by a BSD-style`
	`5`	`+// license that can be found in the LICENSE file.`
	`6`	`+`
	`7`	`+// issue 5809: 6g and 8g attempted to constant propagate indexed LEA`
	`8`	`+`
	`9`	`+package main`
	`10`	`+`
	`11`	`+import"fmt"`
	`12`	`+`
	`13`	`+funcmain() {`
	`14`	`+constd16="0123456789ABCDEF"`
	`15`	`+k:=0x1234`
	`16`	`+varx [4]byte`
	`17`	`+`
	`18`	`+x[0]=d16[k>>12&0xf]`
	`19`	`+x[1]=d16[k>>8&0xf]`
	`20`	`+x[2]=d16[k>>4&0xf]`
	`21`	`+x[3]=d16[k&0xf]`
	`22`	`+`
	`23`	`+ifx!= [4]byte{'1','2','3','4'} {`
	`24`	`+fmt.Println(x)`
	`25`	`+panic("x != [4]byte{'1','2','3','4'}")`
	`26`	`+}`
	`27`	`+}`

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