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8g: respect ullman numbers in float comparison
Fixes #602. R=ken2 CC=golang-dev https://golang.org/cl/212045
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@ -848,7 +848,7 @@ bgen(Node *n, int true, Prog *to)
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}
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if(isslice(nl->type)) {
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// only valid to cmp darray to literal nil
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// front end should only leave cmp to literal nil
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if((a != OEQ && a != ONE) || nr->op != OLITERAL) {
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yyerror("illegal array comparison");
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break;
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@ -867,7 +867,7 @@ bgen(Node *n, int true, Prog *to)
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}
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if(isinter(nl->type)) {
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// front end shold only leave cmp to literal nil
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// front end should only leave cmp to literal nil
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if((a != OEQ && a != ONE) || nr->op != OLITERAL) {
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yyerror("illegal interface comparison");
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break;
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@ -899,10 +899,16 @@ bgen(Node *n, int true, Prog *to)
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nodreg(&ax, types[TUINT16], D_AX);
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et = simsimtype(nr->type);
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if(et == TFLOAT64) {
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// easy - do in FPU
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cgen(nr, &tmp);
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cgen(nl, &tmp);
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gins(AFUCOMPP, &tmp, &n2);
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if(nl->ullman > nr->ullman) {
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cgen(nl, &tmp);
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cgen(nr, &tmp);
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gins(AFXCHD, &tmp, &n2);
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} else {
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cgen(nr, &tmp);
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cgen(nl, &tmp);
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}
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gins(AFUCOMIP, &tmp, &n2);
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gins(AFMOVDP, &tmp, &tmp); // annoying pop but still better than STSW+SAHF
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} else {
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// TODO(rsc): The moves back and forth to memory
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// here are for truncating the value to 32 bits.
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@ -916,9 +922,9 @@ bgen(Node *n, int true, Prog *to)
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cgen(nl, &t2);
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gmove(&t2, &tmp);
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gins(AFCOMFP, &t1, &tmp);
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gins(AFSTSW, N, &ax);
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gins(ASAHF, N, N);
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}
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gins(AFSTSW, N, &ax);
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gins(ASAHF, N, N);
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if(a == OEQ) {
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// neither NE nor P
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p1 = gbranch(AJNE, T);
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33
test/fixedbugs/bug258.go
Normal file
33
test/fixedbugs/bug258.go
Normal file
@ -0,0 +1,33 @@
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// $G $D/$F.go && $L $F.$A && ./$A.out
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// Copyright 2010 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package main
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import "math"
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func f() float64 {
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math.Pow(2, 2)
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return 1
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}
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func main() {
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for i := 0; i < 10; i++ {
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// 386 float register bug used to load constant before call
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if -5 < f() {
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} else {
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println("BUG 1")
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return
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}
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if f() > -7 {
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} else {
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println("BUG 2")
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}
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if math.Pow(2, 3) != 8 {
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println("BUG 3")
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}
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}
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}
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