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turn this conditional into something humans might actually

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be able to understand ;-)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79311 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2009-08-18 04:30:35 +00:00
parent 2c785880ea
commit a006d4e60d
1 changed files with 25 additions and 8 deletions
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33
lib/CodeGen/MachineBasicBlock.cpp
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@ -128,14 +128,31 @@ MachineBasicBlock::iterator MachineBasicBlock::getFirstTerminator() {
return I; return I;
} }
bool bool MachineBasicBlock::isOnlyReachableByFallthrough() const {
MachineBasicBlock::isOnlyReachableByFallthrough() const { // If this is a landing pad, it isn't a fall through. If it has no preds,
return !isLandingPad() && // then nothing falls through to it.
!pred_empty() && if (isLandingPad() || pred_empty())
next(pred_begin()) == pred_end() && return false;
(*pred_begin())->isLayoutSuccessor(this) &&
((*pred_begin())->empty() || // If there isn't exactly one predecessor, it can't be a fall through.
!(*pred_begin())->back().getDesc().isBarrier()); const_pred_iterator PI = pred_begin(), PI2 = PI;
++PI;
if (PI != pred_end())
return false;
// The predecessor has to be immediately before this block.
const MachineBasicBlock *Pred = *PI;
if (!Pred->isLayoutSuccessor(this))
return false;
// If the block is completely empty, then it definitely does fall through.
if (Pred->empty())
return true;
// Otherwise, check the last instruction.
const MachineInstr &LastInst = Pred->back();
return LastInst.getDesc().isBarrier();
} }
void MachineBasicBlock::dump() const { void MachineBasicBlock::dump() const {