#4914: FPU initialization required again
---------------------------------+------------------------------------------
Reporter: aruiz | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 7.2.1
Component: Compiler (NCG) | Version: 7.0.1
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: x86 | Failure: Incorrect result at runtime
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Comment(by aruiz):
I have done as suggested and I think that I have found a small test case
that only requires `QuickCheck`.
I have defined `OnExitHook()` in file `hook.c` to check the FPU status.
The test case is in `bug.hs`.
{{{
$ gcc -c hook.c
$ ghc --make bug.hs hook.o -fforce-recomp
[1 of 1] Compiling Main ( bug.hs, bug.o )
Linking bug ...
$ ./bug
True
140
+++ OK, passed 100 tests.
OnExitHook: NONEMPTY FPU Stack (7)
}}}
The stack seems to be ok after normal operations, but using functions in
`QuickCheck` we get the problem. This can be observed if we comment out
line 8 in `bug.hs`:
{{{
$ ghc --make bug.hs hook.o -fforce-recomp
[1 of 1] Compiling Main ( bug.hs, bug.o )
Linking bug ...
$ ./bug
True
140
OnExitHook: FPU STACK OK
}}}
I know very little assembler, so please verify that this makes sense. I
have some confidence in the stack check used in the hook for the following
reason: in the hmatrix tests which expose the problem I have inserted the
check at the beginning of the foreign calls and only call finit if the
stack is non-empty. Doing this all errors disappear.
Please let me know if you need more info.
I have used `ghc-7.0.2-i386-unknown-linux.tar.bz2` and
`QuickCheck-2.4.0.1`.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4914#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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