[PATCH] D42600: [CodeGen][Shrink-wrap]split restore point

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers added a comment.

In D42600#4267396 <https://reviews.llvm.org/D42600#4267396>, @sushgokh wrote:

> @nickdesaulniers Does this look good ?
>
>   --- a/llvm/lib/CodeGen/ShrinkWrap.cpp
>   +++ b/llvm/lib/CodeGen/ShrinkWrap.cpp
>   @@ -601,6 +601,16 @@ bool ShrinkWrap::postShrinkWrapping(bool HasCandidate, MachineFunction &MF,
>                                    CleanPreds, TII, RS))
>        return false;
>   
>   +  // FIXME: Currently, we bail out of optimisation if any of the DirtyPreds has
>   +  // INLINEASM_BR instruction. Also, if restore pt block address is taken, we
>   +  // need to make suitable changes post restore point split
>   +  for (MachineBasicBlock *BB : DirtyPreds)

Rather than scan every instruction in the block, I think you can use
`MachineBasicBlock::isInlineAsmBrIndirectTarget()`
Perhaps we can do that before even adding such an MBB to DirtyPreds?

> +    for (const MachineInstr &MI : *BB)
> +      if (MI.getOpcode() == TargetOpcode::INLINEASM_BR)
> +        for (const MachineOperand &MO : MI.operands())
> +          if (MO.isMBB() && MO.getMBB() == InitRestore)
> +            return false;
> +
>
>   // Trying to reach out to the new save point which dominates all dirty blocks.
>   MachineBasicBlock *NewSave =
>       FindIDom<>(**DirtyPreds.begin(), DirtyPreds, *MDT, false);
>
>   




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