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Re: Non-call exceptions versus cse


Richard Kenner writes:
 >     > I think both are needed: you set a flag if you cross an EH (but not just
 >     > a block) boundary and you test that flag if the insn may trap.
 > 
 >     Why do you think you need to distinguish?  This is no
 >     different from a branch -- it's a control-flow transfer.
 > 
 > I'm sorry, you lost me.  Distinguish between what and what?
 > 
 > Why does it make a difference if we move a trapping insn into another
 > basic block if both are in the same EH region?

The idea is that

  {
    int tmp = <may trap operation>;
    var = tmp;
  }

should not update var if the operation traps.

Andrew.


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