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author | Keith Randall <khr@golang.org> | 2015-01-15 14:39:58 -0800 |
---|---|---|
committer | Andrew Gerrand <adg@golang.org> | 2015-02-17 06:48:55 +0000 |
commit | 2b7d0b4c0d784d57ffc29cec2bdd167728d46f3c (patch) | |
tree | e8d7e0ad193f67cb88296852cb79b669e29ad03b | |
parent | 5caa9d15f26a088d3c75a183d70d4bf3a355200e (diff) | |
download | go-2b7d0b4c0d784d57ffc29cec2bdd167728d46f3c.tar.gz go-2b7d0b4c0d784d57ffc29cec2bdd167728d46f3c.zip |
[release-branch.go1.4] cmd/5g: make sure we normalize after unary ops on small types
We were failing ^uint16(0xffff) == 0, as we computed 0xffff0000 instead.
I could only trigger a failure for the above case, the other two tests
^uint16(0xfffe) == 1 and -uint16(0xffff) == 1 didn't seem to fail
previously. Somehow they get MOVHUs inserted for other reasons (used
by CMP instead of TST?). I fixed OMINUS anyway, better safe than
sorry.
Fixes #9604
Change-Id: I4c2d5bdc667742873ac029fdbe3db0cf12893c27
Reviewed-on: https://go-review.googlesource.com/2940
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
(cherry picked from commit daa64ddfe64dda368e80cf224dc485fa63386f81)
Reviewed-on: https://go-review.googlesource.com/5002
-rw-r--r-- | src/cmd/5g/cgen.c | 11 | ||||
-rw-r--r-- | test/fixedbugs/issue9604.go | 29 |
2 files changed, 34 insertions, 6 deletions
diff --git a/src/cmd/5g/cgen.c b/src/cmd/5g/cgen.c index c535cfbefb..87c64f6e81 100644 --- a/src/cmd/5g/cgen.c +++ b/src/cmd/5g/cgen.c @@ -236,18 +236,14 @@ cgen(Node *n, Node *res) cgen(nl, &n1); nodconst(&n2, nl->type, -1); gins(a, &n2, &n1); - gmove(&n1, res); - regfree(&n1); - goto ret; + goto norm; case OMINUS: regalloc(&n1, nl->type, N); cgen(nl, &n1); nodconst(&n2, nl->type, 0); gins(optoas(OMINUS, nl->type), &n2, &n1); - gmove(&n1, res); - regfree(&n1); - goto ret; + goto norm; // symmetric binary case OAND: @@ -483,12 +479,15 @@ abop: // asymmetric binary cgen(nl, &n1); } gins(a, &n2, &n1); +norm: // Normalize result for types smaller than word. if(n->type->width < widthptr) { switch(n->op) { case OADD: case OSUB: case OMUL: + case OCOM: + case OMINUS: gins(optoas(OAS, n->type), &n1, &n1); break; } diff --git a/test/fixedbugs/issue9604.go b/test/fixedbugs/issue9604.go new file mode 100644 index 0000000000..cd9e9e49e5 --- /dev/null +++ b/test/fixedbugs/issue9604.go @@ -0,0 +1,29 @@ +// run + +// Copyright 2015 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 + +var x uint16 = 0xffff +var y uint16 = 0xfffe +var a uint16 = 0x7000 +var b uint16 = 0x9000 + +func main() { + // Make sure we truncate to smaller-width types after evaluating expressions. + // This is a problem for arm where there is no 16-bit comparison op. + if ^x != 0 { + panic("^uint16(0xffff) != 0") + } + if ^y != 1 { + panic("^uint16(0xfffe) != 1") + } + if -x != 1 { + panic("-uint16(0xffff) != 1") + } + if a+b != 0 { + panic("0x7000+0x9000 != 0") + } +} |