From 5dda3bc2fd0616f8789cc7f2919d2af49fc64a66 Mon Sep 17 00:00:00 2001

From: Michael Hudson-Doyle <[email protected]>

Date: Fri, 6 Nov 2015 10:10:07 +1300

Subject: [PATCH 40/63] [release-branch.go1.5] cmd/internal/obj/ppc64: fix

 assembly of SRADCC with immediate

sradi and sradi. hide the top bit of their immediate argument apart from the

rest of it, but the code only handled the sradi case.

I'm pretty sure this is the only instruction missing (a couple of the rotate

instructions encode their immediate the same way but their handling looks OK).

This fixes the failure of "GOARCH=amd64 ~/go/bin/go install -v runtime" as

reported in the bug.

Fixes #11987

Change-Id: I0cdefcd7a04e0e8fce45827e7054ffde9a83f589

Reviewed-on: https://go-review.googlesource.com/16710

Reviewed-by: Minux Ma <[email protected]>

Reviewed-on: https://go-review.googlesource.com/16983

Run-TryBot: Austin Clements <[email protected]>

Reviewed-by: Ian Lance Taylor <[email protected]>

Reviewed-by: Russ Cox <[email protected]>

---

 src/cmd/internal/obj/ppc64/asm9.go |  2 +-

 test/fixedbugs/issue11987.go       | 23 +++++++++++++++++++++++

 2 files changed, 24 insertions(+), 1 deletion(-)

 create mode 100644 test/fixedbugs/issue11987.go

diff --git a/src/cmd/internal/obj/ppc64/asm9.go b/src/cmd/internal/obj/ppc64/asm9.go

index 2955a00..f074d90 100644

--- a/src/cmd/internal/obj/ppc64/asm9.go

+++ b/src/cmd/internal/obj/ppc64/asm9.go

@@ -2173,7 +2173,7 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {

 			r = int(p.To.Reg)

 		}

 		o1 = AOP_RRR(uint32(opirr(ctxt, int(p.As))), uint32(r), uint32(p.To.Reg), uint32(v)&31)

-		if p.As == ASRAD && (v&0x20 != 0) {

+		if (p.As == ASRAD || p.As == ASRADCC) && (v&0x20 != 0) {

 			o1 |= 1 << 1 /* mb[5] */

 		}

diff --git a/test/fixedbugs/issue11987.go b/test/fixedbugs/issue11987.go

new file mode 100644

index 0000000..78fc28b

--- /dev/null

+++ b/test/fixedbugs/issue11987.go

@@ -0,0 +1,23 @@

+// run

+

+// Copyright 2015 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.

+

+// Issue 11987. The ppc64 SRADCC instruction was misassembled in a way

+// lost bit 5 of the immediate so v>>32 was assembled as v>>0.  SRADCC

+// is only ever inserted by peep so it's hard to be sure when it will

+// be used. This formulation worked when the bug was fixed.

+

+package main

+

+import "fmt"

+

+var v int64 = 0x80000000

+

+func main() {

+	s := fmt.Sprintf("%v", v>>32 == 0)

+	if s != "true" {

+		fmt.Printf("BUG: v>>32 == 0 evaluated as %q\n", s)

+	}

+}

-- 

2.6.1