diff options
| author | Anthony Martin <ality@pbrane.org> | 2011-05-16 22:14:56 -0400 |
|---|---|---|
| committer | Russ Cox <rsc@golang.org> | 2011-05-16 22:14:56 -0400 |
| commit | f570d9d7657edcccb52b2ec9a55cb90a28602d57 (patch) | |
| tree | 694571bbfa4f67fc2a829f8267c86d58622b1eeb | |
| parent | de7c28fe7689fccbf7b415eb5f5defb8b43ba390 (diff) | |
| download | go-f570d9d7657edcccb52b2ec9a55cb90a28602d57.tar.gz go-f570d9d7657edcccb52b2ec9a55cb90a28602d57.zip | |
8g: fix conversion from float to uint64
The code for converting negative floats was
incorrectly loading an FP control word from
the stack without ever having stored it there.
Thanks to Lars Pensjö for reporting this bug.
R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/4515091
| -rw-r--r-- | src/cmd/8g/gsubr.c | 4 | ||||
| -rw-r--r-- | test/fixedbugs/bug341.go | 22 |
2 files changed, 24 insertions, 2 deletions
diff --git a/src/cmd/8g/gsubr.c b/src/cmd/8g/gsubr.c index e3f239d605..5ad35fdce7 100644 --- a/src/cmd/8g/gsubr.c +++ b/src/cmd/8g/gsubr.c @@ -1429,11 +1429,11 @@ gmove(Node *f, Node *t) split64(t, &tlo, &thi); gins(AXORL, ncon(0x80000000), &thi); // + 2^63 patch(p3, pc); - patch(p1, pc); splitclean(); - // restore rounding mode gins(AFLDCW, &t1, N); + + patch(p1, pc); return; /* diff --git a/test/fixedbugs/bug341.go b/test/fixedbugs/bug341.go new file mode 100644 index 0000000000..8ee52e1ef0 --- /dev/null +++ b/test/fixedbugs/bug341.go @@ -0,0 +1,22 @@ +// $G $D/$F.go && $L $F.$A && ./$A.out || echo BUG: bug341 + +// 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. + +// Used to panic because 8g was generating incorrect +// code for converting a negative float to a uint64. + +package main + +func main() { + var x float32 = -2.5 + + _ = uint64(x) + _ = float32(0) +} +/* +panic: runtime error: floating point error + +[signal 0x8 code=0x6 addr=0x8048c64 pc=0x8048c64] +*/ |