diff options
| -rw-r--r-- | src/cmd/gc/walk.c | 7 | ||||
| -rw-r--r-- | test/fixedbugs/issue5841.go | 16 |
2 files changed, 23 insertions, 0 deletions
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c index d9c6341b43..e8ebd28924 100644 --- a/src/cmd/gc/walk.c +++ b/src/cmd/gc/walk.c @@ -1338,6 +1338,13 @@ walkexpr(Node **np, NodeList **init) fatal("missing switch %O", n->op); ret: + // Expressions that are constant at run time but not + // considered const by the language spec are not turned into + // constants until walk. For example, if n is y%1 == 0, the + // walk of y%1 may have replaced it by 0. + // Check whether n with its updated args is itself now a constant. + evconst(n); + ullmancalc(n); if(debug['w'] && n != N) diff --git a/test/fixedbugs/issue5841.go b/test/fixedbugs/issue5841.go new file mode 100644 index 0000000000..cfc4a504c5 --- /dev/null +++ b/test/fixedbugs/issue5841.go @@ -0,0 +1,16 @@ +// build + +// Copyright 2013 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 5841: 8g produces invalid CMPL $0, $0. +// Similar to issue 5002, used to fail at link time. + +package main + +func main() { + var y int + if y%1 == 0 { + } +} |