cmd/6g: fix float32/64->uint64 conversion
CVTSS2SQ's rounding mode is controlled by the RC field of MXCSR;
as we specifically need truncate semantic, we should use CVTTSS2SQ.
Fixes #3804.
R=rsc, r
CC=golang-dev
https://golang.org/cl/6352079
diff --git a/test/fixedbugs/bug447.go b/test/fixedbugs/bug447.go
new file mode 100644
index 0000000..a4c871b
--- /dev/null
+++ b/test/fixedbugs/bug447.go
@@ -0,0 +1,105 @@
+// runoutput
+
+// 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.
+
+// Issue 3804
+// test all possible float -> integer conversions
+
+package main
+
+import (
+ "bytes"
+ "fmt"
+ "strings"
+)
+
+var (
+ intWidths = []int{8, 16, 32, 64} // int%d and uint%d
+ floatWidths = []int{32, 64} // float%d
+)
+
+func main() {
+
+ var names, funcs bytes.Buffer
+
+ for _, iWidth := range intWidths {
+ for _, typ := range []string{"int", "uint"} {
+ var segs bytes.Buffer
+ itype := fmt.Sprintf("%s%d", typ, iWidth)
+ names.WriteString("\ttest" + itype + ",\n")
+ for _, fWidth := range floatWidths {
+ ftype := fmt.Sprintf("float%d", fWidth)
+ seg := strings.Replace(testSegment, "$F", ftype, -1)
+ seg = strings.Replace(seg, "$I", itype, -1)
+ segs.WriteString(seg)
+ }
+ body := strings.Replace(testFunc, "$I", itype, -1)
+ if typ[0] == 'u' {
+ body = strings.Replace(body, "$TEST", " || i < 0", 1)
+ } else {
+ body = strings.Replace(body, "$TEST", "", 1)
+ }
+ body = strings.Replace(body, "$TESTSEGMENTS", segs.String(), 1)
+ funcs.WriteString(body)
+ }
+ }
+
+ program = strings.Replace(program, "$NAMES", names.String(), 1)
+ program = strings.Replace(program, "$FUNCS", funcs.String(), 1)
+ fmt.Print(program)
+}
+
+const testSegment = `
+ f$F := $F(f)
+ if math.Abs(float64(f$F) - f) < 0.05 {
+ if v := $I(f$F); v != $I(i) {
+ fmt.Printf("$I($F(%f)) = %v, expected %v\n", f, v, i)
+ }
+ }`
+
+const testFunc =
+`func test$I(f float64, i int64) {
+ if i != int64($I(i))$TEST {
+ return
+ }
+$TESTSEGMENTS
+}
+`
+
+var program =
+`package main
+
+import (
+ "fmt"
+ "math"
+)
+
+var tests = []struct {
+ f float64
+ i int64
+}{
+ {39.7, 39},
+ {-39.7, -39},
+ {258.6, 258},
+ {-258.6, -258},
+ {65538.9, 65538},
+ {-65538.9, -65538},
+ {4294967298.8, 4294967298},
+ {-4294967298.8, -4294967298},
+}
+
+var funcs = []func(float64, int64){
+$NAMES
+}
+
+$FUNCS
+func main() {
+ for _, t := range tests {
+ for _, f := range funcs {
+ f(t.f, t.i)
+ }
+ }
+}
+`
