[LLVMbugs] [Bug 1786] New: SimplifyCFG leaves unreachable basic blocks

[bugzilla-daemon at cs.uiuc.edu]

http://llvm.org/bugs/show_bug.cgi?id=1786

           Summary: SimplifyCFG leaves unreachable basic blocks
           Product: libraries
           Version: 2.0
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: enhancement
          Priority: P2
         Component: Scalar Optimizations
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: jay.foad at antixlabs.com
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=1209)
 --> (http://llvm.org/bugs/attachment.cgi?id=1209)
bitcode for test case

I run this on the attached bitcode file pre.bc:

$ opt -f -o post.bc pre.bc -simplifycfg

Then in post.bc, basic block bb17 is only reachable from cond_next27, and
cond_next27 is only reachable from bb17. Neither is reachable from the entry
block so they should have been removed.

Running "opt ... -simplifycfg -simplifycfg" still doesn't remove them, but I
guess that's because the pass manager still only runs the pass once, or
something.

If I run simplifycfg again on post.bc, they do get removed.


-- 
Configure bugmail: http://llvm.org/bugs/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.