cgrun072 (optllvm) failing

• Platform: OS X 10.8.4 x86_64
• GHC Version 7.7.20130904 (built with gcc-4.8)

To reproduce this:

$ make test TEST=cgrun072 WAY=optllvm

Expected output (for failure):

=====> cgrun072(optllvm) 172 of 3749 [0, 0, 2]
cd ./codeGen/should_run && '/Users/leroux/Dropbox/src/ghc/ghc-validate/inplace/bin/ghc-stage2' -fforce-recomp -dcore-lint -dcmm-lint -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -o cgrun072 cgrun072.hs -O -fllvm   >cgrun072.comp.stderr 2>&1
cd ./codeGen/should_run && ./cgrun072    </dev/null >cgrun072.run.stdout 2>cgrun072.run.stderr
Actual stdout output differs from expected:
--- ./codeGen/should_run/cgrun072.stdout	2013-09-04 02:22:32.000000000 -0500
+++ ./codeGen/should_run/cgrun072.run.stdout	2013-09-07 03:27:09.000000000 -0500
@@ -1,3 +1,6 @@
 OK
-OK
+FAIL
+   Input: 1480294021
+Expected: 2239642456
+  Actual: -2055324840
 OK
*** unexpected failure for cgrun072(optllvm)

The failing test case is test_bSwap32.

Here are some relevant snippets. bswap and cgrun072 were added in #7902 (closed).

https://github.com/ghc/testsuite/blob/master/tests/codeGen/should_run/cgrun072.hs:

bswap32 :: Word32 -> Word32
bswap32 (W32# w#) = W32# (byteSwap32# w#)

slowBswap32 :: Word32 -> Word32
slowBswap32 w =
         (w `shiftR` 24)             .|. (w `shiftL` 24)
     .|. ((w `shiftR` 8) .&. 0xff00) .|. ((w .&. 0xff00) `shiftL` 8)

test_bSwap32 = test casesW32 bswap32 slowBswap32

https://github.com/ghc/packages-ghc-prim/blob/master/cbits/bswap.c#L10-L17:

extern StgWord32 hs_bswap32(StgWord32 x);
StgWord32
hs_bswap32(StgWord32 x)
{
  return ((x >> 24) | ((x >> 8) & 0xff00) |
          (x << 24) | ((x & 0xff00) << 8));
}

Here are a few things to look at or try.

• https://github.com/ghc/packages-ghc-prim/blob/master/cbits/bswap.c
• https://github.com/ghc/ghc/tree/master/compiler/llvmGen
• Maybe take an object dump and take what's going on.
• gdb debugging?

Trac metadata

Trac field	Value
Version	7.6.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler (LLVM)
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	leroux@fezrev.com
Operating system
Architecture