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refactor some code, no functionality change.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50094 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2008-04-22 06:36:15 +00:00
parent f29984f695
commit d38c14e6ed
1 changed files with 13 additions and 2 deletions
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15
lib/Transforms/Scalar/JumpThreading.cpp
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@ -57,6 +57,8 @@ namespace {
bool runOnFunction(Function &F);
bool ThreadBlock(BasicBlock *BB);
void ThreadEdge(BasicBlock *BB, BasicBlock *PredBB, BasicBlock *SuccBB);
bool ProcessJumpOnPHI(PHINode *PN);
};
char JumpThreading::ID = 0;
RegisterPass<JumpThreading> X("jump-threading", "Jump Threading");
@ -158,8 +160,17 @@ bool JumpThreading::ThreadBlock(BasicBlock *BB) {
// See if this is a phi node in the current block.
PHINode *PN = dyn_cast<PHINode>(Condition);
if (!PN || PN->getParent() != BB) return false;
if (PN && PN->getParent() == BB)
return ProcessJumpOnPHI(PN);
return false;
}
/// ProcessJumpOnPHI - We have a conditional branch of switch on a PHI node in
/// the current block. See if there are any simplifications we can do based on
/// inputs to the phi node.
///
bool JumpThreading::ProcessJumpOnPHI(PHINode *PN) {
// See if the phi node has any constant values. If so, we can determine where
// the corresponding predecessor will branch.
unsigned PredNo = ~0U;
@ -177,6 +188,7 @@ bool JumpThreading::ThreadBlock(BasicBlock *BB) {
return false;
// See if the cost of duplicating this block is low enough.
BasicBlock *BB = PN->getParent();
unsigned JumpThreadCost = getJumpThreadDuplicationCost(BB);
if (JumpThreadCost > Threshold) {
DOUT << " Not threading BB '" << BB->getNameStart()
@ -210,7 +222,6 @@ bool JumpThreading::ThreadBlock(BasicBlock *BB) {
".thr_comm", this);
}
DOUT << " Threading edge from '" << PredBB->getNameStart() << "' to '"
<< SuccBB->getNameStart() << "' with cost: " << JumpThreadCost
<< ", across block:\n "