[LLVMdev] DominatorTree not updated properly after calling the llvm::SplitBlock.

[Paul Vario]

Hi Fellows,

      I am writing a pass that requires the DominatorTree pass. In the
runOnFunction of my own pass, I call llvm::SplitBlock to split a block
(%for.end) at it's first insert point. Then, when I dump my dominator tree
immediately after, I can see the newly split %for.end.split, but its
DFSNumIn and DFSNumOut are not properly updated in llvm::SplitBlock (i.e.,
still the initialized -1). At the same time, the DT->dump() results also
show that DFSInfoValid equals false! I could not figure out what I did
wrong, b/c it seems all the analysis updating should be handled by
llvm::SplitBlock. Any suggestions on how to approach this situation? Thanks
a bunch in advance.


-------------------------  The actual dump of my dominator tree after
SplitBlock --------------------

Inorder Dominator Tree: DFSNumbers invalid: 1 slow queries.
  [1] %entry.barrier {0,27}
    [2] %entry {1,26}
      [3] %for.cond {2,25}
        [4] %for.body {3,6}
          [5] %for.inc {4,5}
        [4] %for.end {7,24}
          *[5] %for.end.split {4294967295,4294967295}*
            [6] %if.then {8,15}
              [7] %if.then13 {9,10}
              [7] %if.end {11,12}
              [7] %if.then.if.end_crit_edge {13,14}
            [6] %if.end14 {16,21}
              [7] %exit.b4.barrier {17,20}
                [8] %exit.barrier {18,19}
            [6] %for.end.if.end14_crit_edge {22,23}
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