[llvm-commits] patch

[Bruno Cardoso Lopes]

LGTM, one minor note:

On Fri, Apr 1, 2011 at 3:10 PM, Akira Hatanaka <ahatanak at gmail.com> wrote:
> This patch modifies MipsAsmPrinter::isBlockOnlyReachableByFallthrough so
> that it handles delay slots correctly.
>
>
> Index: lib/Target/Mips/MipsAsmPrinter.cpp
> ===================================================================
> --- lib/Target/Mips/MipsAsmPrinter.cpp  (revision 128718)
> +++ lib/Target/Mips/MipsAsmPrinter.cpp  (working copy)
> @@ -247,7 +247,33 @@
>      if (isa<SwitchInst>(bb->getTerminator()))
>        return false;
>
> -  return AsmPrinter::isBlockOnlyReachableByFallthrough(MBB);
> +  // If this is a landing pad, it isn't a fall through.  If it has no
> preds,
> +  // then nothing falls through to it.
> +  if (MBB->isLandingPad() || MBB->pred_empty())
> +    return false;
> +
> +  // If there isn't exactly one predecessor, it can't be a fall through.
> +  MachineBasicBlock::const_pred_iterator PI = MBB->pred_begin(), PI2 = PI;
> +  ++PI2;
> +
> +  if (PI2 != MBB->pred_end())
> +    return false;
> +
> +  // The predecessor has to be immediately before this block.
> +  if (!Pred->isLayoutSuccessor(MBB))
> +    return false;
> +
> +  // If the block is completely empty, then it definitely does fall
> through.
> +  if (Pred->empty())
> +    return true;
> +
> +  // Otherwise, check the last instruction.
> +  // Check if the last terminator is an unconditional branch.
> +  MachineBasicBlock::const_iterator I = Pred->end();
> +  while (I != Pred->begin() && !(--I)->getDesc().isTerminator())
> +    ;

Use:

while (I != Pred->begin() && !(--I)->getDesc().isTerminator());

Instead of:

while (I != Pred->begin() && !(--I)->getDesc().isTerminator())
   ;

-- 
Bruno Cardoso Lopes
http://www.brunocardoso.cc