[LLVMbugs] [Bug 1502] NEW: live-interval trouble with exception handling

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=1502

           Summary: live-interval trouble with exception handling
           Product: new-bugs
           Version: unspecified
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: new bugs
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: baldrick at free.fr


Logically speaking, the exception register and exception selector register
should be marked as live-in on landing pads.  (Currently they are marked
live-in on the block containing the EXCEPTIONADDR/EHSELECTION selections,
which seems wrong).  I wrote a patch to fix this, but then live-intervals
blows up on several testcases in the testsuite, for example:
(1) CodeGen/Generic/2007-04-14-EHSelectorCrash.ll.  Here the problem seems
to be that there is no landing pad but there is a EHSELECTION instruction.
So the exception selector register is used without being marked live-in
anywhere.
(2) CodeGen/Generic/2007-06-06-CriticalEdgeLandingPad.ll.  Here the registers
are not used in the landing pad itself (they are used in a sucessor).
Live-intervals doesn't seem to like having registers marked as live-in without
actually being used in that machine basic block.

Could a live-intervals expert please take a look?



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