[LLVMbugs] [Bug 16108] New: Wrong constant folding

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=16108

            Bug ID: 16108
           Summary: Wrong constant folding
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: Backend: X86
          Assignee: unassignedbugs at nondot.org
          Reporter: ishiura-compiler at ml.kwansei.ac.jp
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified

LLVM (git) + clang (3.4) for i386 miscompiles the following code
where LLONG_MAX == 9223372036854775807.

    $ cat error.c

    int main (void)
    {
      int x = 1;
      long long t = 1LL;
      t = 1LL << (( x << 8 ) + ( -224 ));
      if ( t != 4294967296LL ){ __builtin_abort(); }
      return 0;
    }

    $ clang error.c
    $ ./a.out
    Aborted (core dumped)

There was no problem with an x86_64 target.

    $ clang -v
    clang version 3.4 (http://llvm.org/git/clang.git
    800ff45b49e306a5706f249d3289281dc224dcb3)
    (http://llvm.org/git/llvm.git
    f8cd1ee516c845285fd6a7ee27abb5339c5f3fba)
    Target: i386-pc-linux-gnu
    Thread model: posix

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