Hi Gang-Ryung!
Your reverse iteration of instructions in the BB
> * for (BasicBlock::iterator II = BB->end(); II != BB->begin(); )
*{
>
> Instruction &I = *--II;
>
> if (isLoopInvariantInst(I) && canSinkOrHoistInst(I)
&&
> isSafeToExecuteUnconditionally(I))
> * hoist(I);*
> }
looks perfectly valid.
If I remember correctly, the (operator--) on Instruction has a buggy
assert, but that should not trigger in your case. (Adding unit tests for
reverse iteration is on my TODO list.)
I suspect that your "hoist(I)" call removes the instruction
"I" from the
BB and puts it into the first position of another basic block. This could
mess up the "II != BB->begin()" test.
Hope this helps!
Cheers,
Gabor
