undo 4439044

cannot use regalloc with floating point on 386.
will redo some other way.

R=ken2
CC=golang-dev
https://golang.org/cl/4439045

src/cmd/gc/cplx.c

@@ -21,7 +21,7 @@ void
 complexmove(Node *f, Node *t)
 {
 	int ft, tt;
-	Node n1, n2, n3, n4, t3, t4;
+	Node n1, n2, n3, n4;
 
 	if(debug['g']) {
 		dump("\ncomplexmove-f", f);
@@ -54,21 +54,8 @@ complexmove(Node *f, Node *t)
 		subnode(&n1, &n2, f);
 		subnode(&n3, &n4, t);
 
-		// Copy fully into registers before doing stores,
-		// in case the source and destination overlap.
-		// Might be picking up a complex128 from one
-		// location on the stack and writing it 8 bytes
-		// (half a complex128) later, in which case the
-		// first write would smash the source for the second read.
-		regalloc(&t3, types[tt+TFLOAT64-TCOMPLEX128], N);
-		regalloc(&t4, types[tt+TFLOAT64-TCOMPLEX128], N);
-		cgen(&n1, &t3);
-		cgen(&n2, &t4);
-
-		cgen(&t3, &n3);
-		cgen(&t4, &n4);
-		regfree(&t3);
-		regfree(&t4);
+		cgen(&n1, &n3);
+		cgen(&n2, &n4);
 		break;
 	}
 }

test/fixedbugs/bug329.go

-// $G $D/$F.go && $L $F.$A && ./$A.out
-
-// Copyright 2011 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.
-
-// Test that when moving a complex128 returned by one function
-// into the argument position for another function, the right thing
-// happens, even when the two positions half-overlap.
-
-package main
-
-type Value struct {
-	X interface{}
-	Y int
-}
-
-type Struct struct {
-	X complex128
-}
-
-const magic = 1+2i
-
-func (Value) Complex(x complex128) {
-	if x != magic {
-		println(x)
-		panic("bad complex magic")
-	}
-}
-
-func f(x *byte, y, z int) complex128 {
-	return magic
-}
-
-func (Value) Struct(x Struct) {
-	if x.X != magic {
-		println(x.X)
-		panic("bad struct magic")
-	}
-}
-
-func f1(x *byte, y, z int) Struct {
-	return Struct{magic}
-}
-
-func main() {
-	var v Value
-	v.Struct(f1(nil, 0, 0))  // ok
-	v.Complex(f(nil, 0, 0))  // used to fail
-}