mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-08-17 05:29:24 +00:00
Fix diamond shape ifcvt bugs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37444 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
parent
1d4eb6ab0d
commit
993fc9594e
@ -284,7 +284,7 @@ void IfConverter::StructuralAnalysis(MachineBasicBlock *BB) {
|
||||
}
|
||||
} else if (TrueBBI.TrueBB == FalseBBI.TrueBB && CanRevCond &&
|
||||
TrueBBI.BB->pred_size() == 1 &&
|
||||
TrueBBI.BB->pred_size() == 1 &&
|
||||
FalseBBI.BB->pred_size() == 1 &&
|
||||
// Check the 'true' and 'false' blocks if either isn't ended with
|
||||
// a branch. If the block does not fallthrough to another block
|
||||
// then we need to add a branch to its successor.
|
||||
@ -301,7 +301,7 @@ void IfConverter::StructuralAnalysis(MachineBasicBlock *BB) {
|
||||
// TBB FBB
|
||||
// \ /
|
||||
// TailBB
|
||||
// Note MBB can be empty in case both TBB and FBB are return blocks.
|
||||
// Note TailBB can be empty.
|
||||
BBI.Kind = ICDiamond;
|
||||
TrueBBI.Kind = FalseBBI.Kind = ICChild;
|
||||
BBI.TailBB = TrueBBI.TrueBB;
|
||||
@ -611,74 +611,58 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI) {
|
||||
--TrueBBI.NonPredSize;
|
||||
}
|
||||
|
||||
// Check the 'true' and 'false' blocks if either isn't ended with a branch.
|
||||
// Either the block fallthrough to another block or it ends with a
|
||||
// return. If it's the former, add a branch to its successor.
|
||||
bool TrueNeedBr = !TrueBBI.TrueBB && BBI.TrueBB->succ_size();
|
||||
bool FalseNeedBr = !FalseBBI.TrueBB && BBI.FalseBB->succ_size();
|
||||
|
||||
// Merge the 'true' and 'false' blocks by copying the instructions
|
||||
// from the 'false' block to the 'true' block. That is, unless the true
|
||||
// block would clobber the predicate, in that case, do the opposite.
|
||||
BBInfo *BBI1 = &TrueBBI;
|
||||
BBInfo *BBI2 = &FalseBBI;
|
||||
std::vector<MachineOperand> RevCond(BBI.BrCond);
|
||||
TII->ReverseBranchCondition(RevCond);
|
||||
BBInfo *CvtBBI;
|
||||
if (!TrueBBI.ModifyPredicate) {
|
||||
// Predicate the 'true' block after removing its branch.
|
||||
TrueBBI.NonPredSize -= TII->RemoveBranch(*BBI.TrueBB);
|
||||
PredicateBlock(TrueBBI, BBI.BrCond);
|
||||
|
||||
// Predicate the 'false' block.
|
||||
PredicateBlock(FalseBBI, RevCond, true);
|
||||
|
||||
if (TrueNeedBr)
|
||||
TII->InsertBranch(*BBI.TrueBB, *BBI.TrueBB->succ_begin(), NULL,
|
||||
BBI.BrCond);
|
||||
// Add an unconditional branch from 'false' to to 'false' successor if it
|
||||
// will not be the fallthrough block.
|
||||
if (FalseNeedBr &&
|
||||
!isNextBlock(BBI.BB, *BBI.FalseBB->succ_begin()))
|
||||
InsertUncondBranch(BBI.FalseBB, *BBI.FalseBB->succ_begin(), TII);
|
||||
MergeBlocks(TrueBBI, FalseBBI);
|
||||
CvtBBI = &TrueBBI;
|
||||
} else {
|
||||
// Predicate the 'false' block after removing its branch.
|
||||
FalseBBI.NonPredSize -= TII->RemoveBranch(*BBI.FalseBB);
|
||||
PredicateBlock(FalseBBI, RevCond);
|
||||
|
||||
// Predicate the 'false' block.
|
||||
PredicateBlock(TrueBBI, BBI.BrCond, true);
|
||||
|
||||
// Add a conditional branch from 'false' to 'false' successor if needed.
|
||||
if (FalseNeedBr)
|
||||
TII->InsertBranch(*BBI.FalseBB, *BBI.FalseBB->succ_begin(), NULL,
|
||||
RevCond);
|
||||
// Add an unconditional branch from 'true' to to 'true' successor if it
|
||||
// will not be the fallthrough block.
|
||||
if (TrueNeedBr &&
|
||||
!isNextBlock(BBI.BB, *BBI.TrueBB->succ_begin()))
|
||||
InsertUncondBranch(BBI.TrueBB, *BBI.TrueBB->succ_begin(), TII);
|
||||
MergeBlocks(FalseBBI, TrueBBI);
|
||||
CvtBBI = &FalseBBI;
|
||||
std::vector<MachineOperand> *Cond1 = &BBI.BrCond;
|
||||
std::vector<MachineOperand> *Cond2 = &RevCond;
|
||||
if (TrueBBI.ModifyPredicate) {
|
||||
std::swap(BBI1, BBI2);
|
||||
std::swap(Cond1, Cond2);
|
||||
}
|
||||
|
||||
// Check the 'true' and 'false' blocks if either isn't ended with a branch.
|
||||
// Either the block fallthrough to another block or it ends with a
|
||||
// return. If it's the former, add a branch to its successor.
|
||||
bool NeedBr1 = !BBI1->TrueBB && BBI1->BB->succ_size();
|
||||
bool NeedBr2 = !BBI2->TrueBB && BBI1->BB->succ_size();
|
||||
|
||||
// Predicate the 'true' block after removing its branch.
|
||||
BBI1->NonPredSize -= TII->RemoveBranch(*BBI1->BB);
|
||||
PredicateBlock(*BBI1, *Cond1);
|
||||
|
||||
// Add an early exit branch if needed.
|
||||
if (NeedBr1)
|
||||
TII->InsertBranch(*BBI1->BB, *BBI1->BB->succ_begin(), NULL, *Cond1);
|
||||
|
||||
// Predicate the 'false' block.
|
||||
PredicateBlock(*BBI2, *Cond2, true);
|
||||
|
||||
// Add an unconditional branch from 'false' to to 'false' successor if it
|
||||
// will not be the fallthrough block.
|
||||
if (NeedBr2 && !isNextBlock(BBI2->BB, *BBI2->BB->succ_begin()))
|
||||
InsertUncondBranch(BBI2->BB, *BBI2->BB->succ_begin(), TII);
|
||||
|
||||
// Keep them as two separate blocks if there is an early exit.
|
||||
if (!NeedBr1)
|
||||
MergeBlocks(*BBI1, *BBI2);
|
||||
else if (!isNextBlock(BBI1->BB, BBI2->BB))
|
||||
InsertUncondBranch(BBI1->BB, BBI2->BB, TII);
|
||||
|
||||
// Remove the conditional branch from entry to the blocks.
|
||||
BBI.NonPredSize -= TII->RemoveBranch(*BBI.BB);
|
||||
|
||||
bool OkToIfcvt = true;
|
||||
// Merge the combined block into the entry of the diamond if the entry
|
||||
// block is its only predecessor. Otherwise, insert an unconditional
|
||||
// branch from entry to the if-converted block.
|
||||
if (CvtBBI->BB->pred_size() == 1) {
|
||||
MergeBlocks(BBI, *CvtBBI);
|
||||
CvtBBI = &BBI;
|
||||
OkToIfcvt = false;
|
||||
} else if (!isNextBlock(BBI.BB, CvtBBI->BB))
|
||||
InsertUncondBranch(BBI.BB, CvtBBI->BB, TII);
|
||||
// Merge the combined block into the entry of the diamond.
|
||||
MergeBlocks(BBI, *BBI1);
|
||||
|
||||
// If the if-converted block fallthrough or unconditionally branch into the
|
||||
// tail block, and the tail block does not have other predecessors, then
|
||||
// fold the tail block in as well.
|
||||
BBInfo *CvtBBI = NeedBr1 ? BBI2 : &BBI;
|
||||
if (BBI.TailBB &&
|
||||
BBI.TailBB->pred_size() == 1 && CvtBBI->BB->succ_size() == 1) {
|
||||
CvtBBI->NonPredSize -= TII->RemoveBranch(*CvtBBI->BB);
|
||||
@ -687,11 +671,7 @@ bool IfConverter::IfConvertDiamond(BBInfo &BBI) {
|
||||
TailBBI.Kind = ICDead;
|
||||
}
|
||||
|
||||
// Update block info. BB may be iteratively if-converted.
|
||||
if (OkToIfcvt) {
|
||||
BBI.Kind = ICReAnalyze;
|
||||
ReTryPreds(BBI.BB);
|
||||
}
|
||||
// Update block info.
|
||||
TrueBBI.Kind = ICDead;
|
||||
FalseBBI.Kind = ICDead;
|
||||
|
||||
|
Loading…
Reference in New Issue
Block a user