mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-18 12:29:21 +00:00
Revert r53735. It broke SPEC 464.h264ref.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53757 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
0c141e6673
commit
79c23effe2
@ -2036,12 +2036,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
|
||||
// pred, and if there is only one distinct successor of the predecessor, and
|
||||
// if there are no PHI nodes.
|
||||
//
|
||||
if (MergeBlockIntoPredecessor(BB))
|
||||
return true;
|
||||
|
||||
// Otherwise, if this block only has a single predecessor, and if that block
|
||||
// is a conditional branch, see if we can hoist any code from this block up
|
||||
// into our predecessor.
|
||||
pred_iterator PI(pred_begin(BB)), PE(pred_end(BB));
|
||||
BasicBlock *OnlyPred = *PI++;
|
||||
for (; PI != PE; ++PI) // Search all predecessors, see if they are all same
|
||||
@ -2049,7 +2043,57 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
|
||||
OnlyPred = 0; // There are multiple different predecessors...
|
||||
break;
|
||||
}
|
||||
|
||||
|
||||
BasicBlock *OnlySucc = 0;
|
||||
if (OnlyPred && OnlyPred != BB && // Don't break self loops
|
||||
OnlyPred->getTerminator()->getOpcode() != Instruction::Invoke) {
|
||||
// Check to see if there is only one distinct successor...
|
||||
succ_iterator SI(succ_begin(OnlyPred)), SE(succ_end(OnlyPred));
|
||||
OnlySucc = BB;
|
||||
for (; SI != SE; ++SI)
|
||||
if (*SI != OnlySucc) {
|
||||
OnlySucc = 0; // There are multiple distinct successors!
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
if (OnlySucc) {
|
||||
DOUT << "Merging: " << *BB << "into: " << *OnlyPred;
|
||||
|
||||
// Resolve any PHI nodes at the start of the block. They are all
|
||||
// guaranteed to have exactly one entry if they exist, unless there are
|
||||
// multiple duplicate (but guaranteed to be equal) entries for the
|
||||
// incoming edges. This occurs when there are multiple edges from
|
||||
// OnlyPred to OnlySucc.
|
||||
//
|
||||
while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
|
||||
PN->replaceAllUsesWith(PN->getIncomingValue(0));
|
||||
BB->getInstList().pop_front(); // Delete the phi node.
|
||||
}
|
||||
|
||||
// Delete the unconditional branch from the predecessor.
|
||||
OnlyPred->getInstList().pop_back();
|
||||
|
||||
// Move all definitions in the successor to the predecessor.
|
||||
OnlyPred->getInstList().splice(OnlyPred->end(), BB->getInstList());
|
||||
|
||||
// Make all PHI nodes that referred to BB now refer to Pred as their
|
||||
// source.
|
||||
BB->replaceAllUsesWith(OnlyPred);
|
||||
|
||||
// Inherit predecessors name if it exists.
|
||||
if (!OnlyPred->hasName())
|
||||
OnlyPred->takeName(BB);
|
||||
|
||||
// Erase basic block from the function.
|
||||
M->getBasicBlockList().erase(BB);
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
// Otherwise, if this block only has a single predecessor, and if that block
|
||||
// is a conditional branch, see if we can hoist any code from this block up
|
||||
// into our predecessor.
|
||||
if (OnlyPred)
|
||||
if (BranchInst *BI = dyn_cast<BranchInst>(OnlyPred->getTerminator()))
|
||||
if (BI->isConditional()) {
|
||||
@ -2057,7 +2101,6 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
|
||||
BasicBlock *OtherBB = BI->getSuccessor(BI->getSuccessor(0) == BB);
|
||||
PI = pred_begin(OtherBB);
|
||||
++PI;
|
||||
|
||||
if (PI == pred_end(OtherBB)) {
|
||||
// We have a conditional branch to two blocks that are only reachable
|
||||
// from the condbr. We know that the condbr dominates the two blocks,
|
||||
@ -2065,7 +2108,7 @@ bool llvm::SimplifyCFG(BasicBlock *BB) {
|
||||
// blocks. If so, we can hoist it up to the branching block.
|
||||
Changed |= HoistThenElseCodeToIf(BI);
|
||||
} else {
|
||||
BasicBlock* OnlySucc = NULL;
|
||||
OnlySucc = NULL;
|
||||
for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
|
||||
SI != SE; ++SI) {
|
||||
if (!OnlySucc)
|
||||
|
Loading…
Reference in New Issue
Block a user