[LLVMbugs] [Bug 5458] New: reassociate introduces undef for no apparent reason

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=5458

           Summary: reassociate introduces undef for no apparent reason
           Product: libraries
           Version: trunk
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Scalar Optimizations
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: nlewycky at google.com
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=3803)
 --> (http://llvm.org/bugs/attachment.cgi?id=3803)
reduced .ll testcase

I have no idea what reassociate thinks it's doing. The attached reduced .ll
file shows an example where "opt -reassociate" adds a new 'mul undef, undef'
and an 'add undef, undef', then goes off and uses those in a way that
introduces undefinedness into the program.


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