mirror of
https://github.com/RPCS3/llvm-mirror.git
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factor some code better and move a function, no functionality change.
llvm-svn: 83755
This commit is contained in:
Chris Lattner
parent
525c0272aa
commit
b4e9fb6967
@ -74,8 +74,7 @@ namespace {
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void FindLoopHeaders(Function &F);
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bool ProcessBlock(BasicBlock *BB);
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bool ThreadEdge(BasicBlock *BB, BasicBlock *PredBB, BasicBlock *SuccBB,
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unsigned JumpThreadCost);
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bool ThreadEdge(BasicBlock *BB, BasicBlock *PredBB, BasicBlock *SuccBB);
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BasicBlock *FactorCommonPHIPreds(PHINode *PN, Value *Val);
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bool ProcessBranchOnDuplicateCond(BasicBlock *PredBB, BasicBlock *DestBB);
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bool ProcessSwitchOnDuplicateCond(BasicBlock *PredBB, BasicBlock *DestBB);
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@ -180,46 +179,6 @@ BasicBlock *JumpThreading::FactorCommonPHIPreds(PHINode *PN, Value *Val) {
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}
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/// getJumpThreadDuplicationCost - Return the cost of duplicating this block to
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/// thread across it.
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static unsigned getJumpThreadDuplicationCost(const BasicBlock *BB) {
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/// Ignore PHI nodes, these will be flattened when duplication happens.
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BasicBlock::const_iterator I = BB->getFirstNonPHI();
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// Sum up the cost of each instruction until we get to the terminator. Don't
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// include the terminator because the copy won't include it.
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unsigned Size = 0;
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for (; !isa<TerminatorInst>(I); ++I) {
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// Debugger intrinsics don't incur code size.
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if (isa<DbgInfoIntrinsic>(I)) continue;
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// If this is a pointer->pointer bitcast, it is free.
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if (isa<BitCastInst>(I) && isa<PointerType>(I->getType()))
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continue;
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// All other instructions count for at least one unit.
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++Size;
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// Calls are more expensive. If they are non-intrinsic calls, we model them
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// as having cost of 4. If they are a non-vector intrinsic, we model them
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// as having cost of 2 total, and if they are a vector intrinsic, we model
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// them as having cost 1.
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if (const CallInst *CI = dyn_cast<CallInst>(I)) {
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if (!isa<IntrinsicInst>(CI))
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Size += 3;
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else if (!isa<VectorType>(CI->getType()))
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Size += 1;
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}
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}
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// Threading through a switch statement is particularly profitable. If this
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// block ends in a switch, decrease its cost to make it more likely to happen.
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if (isa<SwitchInst>(I))
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Size = Size > 6 ? Size-6 : 0;
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return Size;
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}
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/// GetBestDestForBranchOnUndef - If we determine that the specified block ends
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/// in an undefined jump, decide which block is best to revector to.
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///
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@ -450,21 +409,13 @@ bool JumpThreading::ProcessBranchOnDuplicateCond(BasicBlock *PredBB,
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ConstantFoldTerminator(BB);
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return true;
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}
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// Otherwise we need to thread from PredBB to DestBB's successor which
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// involves code duplication. Check to see if it is worth it.
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unsigned JumpThreadCost = getJumpThreadDuplicationCost(BB);
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if (JumpThreadCost > Threshold) {
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DEBUG(errs() << " Not threading BB '" << BB->getName()
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<< "' - Cost is too high: " << JumpThreadCost << "\n");
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return false;
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}
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// Next, figure out which successor we are threading to.
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BasicBlock *SuccBB = DestBI->getSuccessor(!BranchDir);
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// Ok, try to thread it!
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return ThreadEdge(BB, PredBB, SuccBB, JumpThreadCost);
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return ThreadEdge(BB, PredBB, SuccBB);
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}
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/// ProcessSwitchOnDuplicateCond - We found a block and a predecessor of that
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@ -724,18 +675,11 @@ bool JumpThreading::ProcessJumpOnPHI(PHINode *PN) {
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// See if the cost of duplicating this block is low enough.
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BasicBlock *BB = PN->getParent();
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unsigned JumpThreadCost = getJumpThreadDuplicationCost(BB);
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if (JumpThreadCost > Threshold) {
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DEBUG(errs() << " Not threading BB '" << BB->getName()
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<< "' - Cost is too high: " << JumpThreadCost << "\n");
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return false;
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}
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// If so, we can actually do this threading. Merge any common predecessors
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// that will act the same.
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BasicBlock *PredBB = FactorCommonPHIPreds(PN, PredCst);
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TerminatorInst *BBTerm = BB->getTerminator();
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// Next, figure out which successor we are threading to.
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@ -751,7 +695,7 @@ bool JumpThreading::ProcessJumpOnPHI(PHINode *PN) {
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}
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// Ok, try to thread it!
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return ThreadEdge(BB, PredBB, SuccBB, JumpThreadCost);
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return ThreadEdge(BB, PredBB, SuccBB);
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}
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/// ProcessJumpOnLogicalPHI - PN's basic block contains a conditional branch
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@ -795,14 +739,6 @@ bool JumpThreading::ProcessBranchOnLogical(Value *V, BasicBlock *BB,
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if (PredNo == ~0U)
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return false;
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// See if the cost of duplicating this block is low enough.
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unsigned JumpThreadCost = getJumpThreadDuplicationCost(BB);
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if (JumpThreadCost > Threshold) {
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DEBUG(errs() << " Not threading BB '" << BB->getName()
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<< "' - Cost is too high: " << JumpThreadCost << "\n");
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return false;
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}
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// If so, we can actually do this threading. Merge any common predecessors
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// that will act the same.
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BasicBlock *PredBB = FactorCommonPHIPreds(PN, PredCst);
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@ -814,7 +750,7 @@ bool JumpThreading::ProcessBranchOnLogical(Value *V, BasicBlock *BB,
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BasicBlock *SuccBB = BB->getTerminator()->getSuccessor(isAnd);
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// Ok, try to thread it!
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return ThreadEdge(BB, PredBB, SuccBB, JumpThreadCost);
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return ThreadEdge(BB, PredBB, SuccBB);
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}
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/// GetResultOfComparison - Given an icmp/fcmp predicate and the left and right
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@ -881,14 +817,6 @@ bool JumpThreading::ProcessBranchOnCompare(CmpInst *Cmp, BasicBlock *BB) {
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if (PredVal == 0)
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return false;
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// See if the cost of duplicating this block is low enough.
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unsigned JumpThreadCost = getJumpThreadDuplicationCost(BB);
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if (JumpThreadCost > Threshold) {
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DEBUG(errs() << " Not threading BB '" << BB->getName()
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<< "' - Cost is too high: " << JumpThreadCost << "\n");
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return false;
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}
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// If so, we can actually do this threading. Merge any common predecessors
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// that will act the same.
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BasicBlock *PredBB = FactorCommonPHIPreds(PN, PredVal);
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@ -897,7 +825,47 @@ bool JumpThreading::ProcessBranchOnCompare(CmpInst *Cmp, BasicBlock *BB) {
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BasicBlock *SuccBB = BB->getTerminator()->getSuccessor(!TrueDirection);
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// Ok, try to thread it!
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return ThreadEdge(BB, PredBB, SuccBB, JumpThreadCost);
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return ThreadEdge(BB, PredBB, SuccBB);
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}
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/// getJumpThreadDuplicationCost - Return the cost of duplicating this block to
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/// thread across it.
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static unsigned getJumpThreadDuplicationCost(const BasicBlock *BB) {
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/// Ignore PHI nodes, these will be flattened when duplication happens.
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BasicBlock::const_iterator I = BB->getFirstNonPHI();
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// Sum up the cost of each instruction until we get to the terminator. Don't
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// include the terminator because the copy won't include it.
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unsigned Size = 0;
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for (; !isa<TerminatorInst>(I); ++I) {
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// Debugger intrinsics don't incur code size.
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if (isa<DbgInfoIntrinsic>(I)) continue;
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// If this is a pointer->pointer bitcast, it is free.
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if (isa<BitCastInst>(I) && isa<PointerType>(I->getType()))
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continue;
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// All other instructions count for at least one unit.
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++Size;
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// Calls are more expensive. If they are non-intrinsic calls, we model them
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// as having cost of 4. If they are a non-vector intrinsic, we model them
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// as having cost of 2 total, and if they are a vector intrinsic, we model
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// them as having cost 1.
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if (const CallInst *CI = dyn_cast<CallInst>(I)) {
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if (!isa<IntrinsicInst>(CI))
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Size += 3;
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else if (!isa<VectorType>(CI->getType()))
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Size += 1;
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}
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}
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// Threading through a switch statement is particularly profitable. If this
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// block ends in a switch, decrease its cost to make it more likely to happen.
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if (isa<SwitchInst>(I))
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Size = Size > 6 ? Size-6 : 0;
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return Size;
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}
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@ -905,8 +873,14 @@ bool JumpThreading::ProcessBranchOnCompare(CmpInst *Cmp, BasicBlock *BB) {
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/// edge from PredBB to SuccBB across BB. Transform the IR to reflect this
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/// change.
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bool JumpThreading::ThreadEdge(BasicBlock *BB, BasicBlock *PredBB,
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BasicBlock *SuccBB, unsigned JumpThreadCost) {
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BasicBlock *SuccBB) {
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unsigned JumpThreadCost = getJumpThreadDuplicationCost(BB);
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if (JumpThreadCost > Threshold) {
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DEBUG(errs() << " Not threading BB '" << BB->getName()
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<< "' - Cost is too high: " << JumpThreadCost << "\n");
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return false;
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}
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// If threading to the same block as we come from, we would infinite loop.
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if (SuccBB == BB) {
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DEBUG(errs() << " Not threading across BB '" << BB->getName()
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