6l/8l: emit correct opcodes to F(SUB|DIV)R?D.

When the destination was not F0, 6l and 8l swapped FSUBD/FSUBRD and
FDIVD/FDIVRD.

R=golang-dev, dave, rsc
CC=golang-dev
https://golang.org/cl/6498092

src/cmd/6l/optab.c

@@ -1199,25 +1199,25 @@ Optab optab[] =
 	{ AFSUBW,	yfmvx,	Px, 0xde,(04) },
 	{ AFSUBL,	yfmvx,	Px, 0xda,(04) },
 	{ AFSUBF,	yfmvx,	Px, 0xd8,(04) },
-	{ AFSUBD,	yfadd,	Px, 0xdc,(04),0xd8,(04),0xdc,(05) },
+	{ AFSUBD,	yfadd,	Px, 0xdc,(04),0xd8,(04),0xdc,(04) },
 
 	{ AFSUBRDP,	yfaddp,	Px, 0xde,(04) },
 	{ AFSUBRW,	yfmvx,	Px, 0xde,(05) },
 	{ AFSUBRL,	yfmvx,	Px, 0xda,(05) },
 	{ AFSUBRF,	yfmvx,	Px, 0xd8,(05) },
-	{ AFSUBRD,	yfadd,	Px, 0xdc,(05),0xd8,(05),0xdc,(04) },
+	{ AFSUBRD,	yfadd,	Px, 0xdc,(05),0xd8,(05),0xdc,(05) },
 
 	{ AFDIVDP,	yfaddp,	Px, 0xde,(07) },
 	{ AFDIVW,	yfmvx,	Px, 0xde,(06) },
 	{ AFDIVL,	yfmvx,	Px, 0xda,(06) },
 	{ AFDIVF,	yfmvx,	Px, 0xd8,(06) },
-	{ AFDIVD,	yfadd,	Px, 0xdc,(06),0xd8,(06),0xdc,(07) },
+	{ AFDIVD,	yfadd,	Px, 0xdc,(06),0xd8,(06),0xdc,(06) },
 
 	{ AFDIVRDP,	yfaddp,	Px, 0xde,(06) },
 	{ AFDIVRW,	yfmvx,	Px, 0xde,(07) },
 	{ AFDIVRL,	yfmvx,	Px, 0xda,(07) },
 	{ AFDIVRF,	yfmvx,	Px, 0xd8,(07) },
-	{ AFDIVRD,	yfadd,	Px, 0xdc,(07),0xd8,(07),0xdc,(06) },
+	{ AFDIVRD,	yfadd,	Px, 0xdc,(07),0xd8,(07),0xdc,(07) },
 
 	{ AFXCHD,	yfxch,	Px, 0xd9,(01),0xd9,(01) },
 	{ AFFREE },

src/cmd/8l/optab.c

@@ -651,25 +651,25 @@ Optab optab[] =
 	{ AFSUBW,	yfmvx,	Px, 0xde,(04) },
 	{ AFSUBL,	yfmvx,	Px, 0xda,(04) },
 	{ AFSUBF,	yfmvx,	Px, 0xd8,(04) },
-	{ AFSUBD,	yfadd,	Px, 0xdc,(04),0xd8,(04),0xdc,(05) },
+	{ AFSUBD,	yfadd,	Px, 0xdc,(04),0xd8,(04),0xdc,(04) },
 
 	{ AFSUBRDP,	yfaddp,	Px, 0xde,(04) },
 	{ AFSUBRW,	yfmvx,	Px, 0xde,(05) },
 	{ AFSUBRL,	yfmvx,	Px, 0xda,(05) },
 	{ AFSUBRF,	yfmvx,	Px, 0xd8,(05) },
-	{ AFSUBRD,	yfadd,	Px, 0xdc,(05),0xd8,(05),0xdc,(04) },
+	{ AFSUBRD,	yfadd,	Px, 0xdc,(05),0xd8,(05),0xdc,(05) },
 
 	{ AFDIVDP,	yfaddp,	Px, 0xde,(07) },
 	{ AFDIVW,	yfmvx,	Px, 0xde,(06) },
 	{ AFDIVL,	yfmvx,	Px, 0xda,(06) },
 	{ AFDIVF,	yfmvx,	Px, 0xd8,(06) },
-	{ AFDIVD,	yfadd,	Px, 0xdc,(06),0xd8,(06),0xdc,(07) },
+	{ AFDIVD,	yfadd,	Px, 0xdc,(06),0xd8,(06),0xdc,(06) },
 
 	{ AFDIVRDP,	yfaddp,	Px, 0xde,(06) },
 	{ AFDIVRW,	yfmvx,	Px, 0xde,(07) },
 	{ AFDIVRL,	yfmvx,	Px, 0xda,(07) },
 	{ AFDIVRF,	yfmvx,	Px, 0xd8,(07) },
-	{ AFDIVRD,	yfadd,	Px, 0xdc,(07),0xd8,(07),0xdc,(06) },
+	{ AFDIVRD,	yfadd,	Px, 0xdc,(07),0xd8,(07),0xdc,(07) },
 
 	{ AFXCHD,	yfxch,	Px, 0xd9,(01),0xd9,(01) },
 	{ AFFREE },

test/fixedbugs/bug453.dir/bug453.go

@@ -0,0 +1,22 @@
+// Copyright 2012 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 main
+
+import (
+	"strconv"
+)
+
+// These functions are implemented in bug453.s
+func bug453a() float64
+func bug453b() float64
+
+func main() {
+	if v := bug453a(); v != -1 {
+		panic("a: bad result, want -1, got " + strconv.FormatFloat(v, 'f', -1, 64))
+	}
+	if v := bug453b(); v != 1 {
+		panic("b: bad result, want 1, got " + strconv.FormatFloat(v, 'f', -1, 64))
+	}
+}

test/fixedbugs/bug453.dir/bug453.s

@@ -0,0 +1,31 @@
+// Copyright 2012 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.
+
+// +build amd64 386
+
+// func bug453a() float64
+TEXT ·bug453a(SB),7,$0
+        FLD1
+        FLD1
+        FADDD F1,F0
+
+        // This should subtract F0 (2) from F1 (1) and put -1 in F1.
+        FSUBRD F0,F1
+
+        FMOVDP  F0,r+0(FP)
+        FMOVDP  F0,r+0(FP)
+        RET
+
+// func bug453b() float64
+TEXT ·bug453b(SB),7,$0
+        FLD1
+        FLD1
+        FADDD F1,F0
+
+        // This should subtract F1 (1) from F0 (2) and put 1 in F1.
+        FSUBD F0,F1
+
+        FMOVDP  F0,r+0(FP)
+        FMOVDP  F0,r+0(FP)
+        RET

test/fixedbugs/bug453.dir/bug453_ref.go

@@ -0,0 +1,15 @@
+// Copyright 2012 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.
+
+// +build !amd64,!386
+
+package main
+
+// These functions are standins for the functions in the .s file on other platforms.
+func bug453a() float64 {
+	return -1
+}
+func bug453b() float64 {
+	return 1
+}

test/fixedbugs/bug453.go

@@ -0,0 +1,7 @@
+// compiledir
+
+// Copyright 2012 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.
+
+ignored