#1042: Floating point exception
-------------------------+--------------------------------------------------
Reporter: dons | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.6
Severity: normal | Keywords:
Difficulty: Unknown | Testcase:
Architecture: x86 | Os: Unknown
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The slightly evil expression:
{{{
(-2147483648::Int) `div` (-1::Int)
}}}
Can produce floating point exceptions in GHCi:
{{{
$ ghci-6.6
___ ___ _
/ _ \ /\ /\/ __(_)
/ /_\// /_/ / / | | GHC Interactive, version 6.6, for Haskell 98.
/ /_\\/ __ / /___| | http://www.haskell.org/ghc/
\____/\/ /_/\____/|_| Type :? for help.
Loading package base ... linking ... done.
Prelude> (-2147483648::Int) `div` (-1::Int)
zsh: floating point exception (core dumped) ghci-6.6
}}}
Compiled:
{{{
$ cat A.hs
main = print $ (-2147483648::Int) `div` (-1::Int)
$ ghc A.hs
$ ./a.out
zsh: floating point exception (core dumped) ./a.out
}}}
Compiled -O:
{{{
$ ghc -O -no-recomp A.hs
$ ./a.out
zsh: floating point exception (core dumped) ./a.out
}}}
In Hugs:
{{{
Hugs.Base> (-2147483648::Int) `div` (-1::Int)
Unexpected signal
}}}
A C test cases:
{{{
$ cat t.c
#include <stdio.h>
int main() {
printf("%d\n",((int)(-2147483648)) / ((int)(-1)));
return 0;
}
$ gcc t.c
t.c: In function `main':
t.c:4: warning: this decimal constant is unsigned only in ISO C90
t.c:4: warning: integer overflow in expression
$ ./a.out
-2147483648
}}}
Another:
{{{
$ cat t.c
#include <stdio.h>
main () {
int i = -2147483648;
int j = -1;
int k = i / j;
printf("%d\n", k);
}
$ gcc t.c
t.c: In function `main':
t.c:4: warning: this decimal constant is unsigned only in ISO C90
$ ./a.out
zsh: floating point exception (core dumped) ./a.out
}}}
What does H98 say about this?
-- Don
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1042>
GHC <http://www.haskell.org/ghc/>
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