// This file implements inlining of a function into a call site, resolving
// parameters and the return value as appropriate.
//
+// The code in this file for handling inlines through invoke
+// instructions preserves semantics only under some assumptions about
+// the behavior of unwinders which correspond to gcc-style libUnwind
+// exception personality functions. Eventually the IR will be
+// improved to make this unnecessary, but until then, this code is
+// marked [LIBUNWIND].
+//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/Cloning.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
-#include "llvm/LLVMContext.h"
#include "llvm/Module.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Attributes.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/DebugInfo.h"
+#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/Utils/Local.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/Support/CallSite.h"
+#include "llvm/Support/IRBuilder.h"
using namespace llvm;
-bool llvm::InlineFunction(CallInst *CI, CallGraph *CG, const TargetData *TD) {
- return InlineFunction(CallSite(CI), CG, TD);
+bool llvm::InlineFunction(CallInst *CI, InlineFunctionInfo &IFI) {
+ return InlineFunction(CallSite(CI), IFI);
+}
+bool llvm::InlineFunction(InvokeInst *II, InlineFunctionInfo &IFI) {
+ return InlineFunction(CallSite(II), IFI);
+}
+
+/// [LIBUNWIND] Look for an llvm.eh.exception call in the given block.
+static EHExceptionInst *findExceptionInBlock(BasicBlock *bb) {
+ for (BasicBlock::iterator i = bb->begin(), e = bb->end(); i != e; i++) {
+ EHExceptionInst *exn = dyn_cast<EHExceptionInst>(i);
+ if (exn) return exn;
+ }
+
+ return 0;
+}
+
+/// [LIBUNWIND] Look for the 'best' llvm.eh.selector instruction for
+/// the given llvm.eh.exception call.
+static EHSelectorInst *findSelectorForException(EHExceptionInst *exn) {
+ BasicBlock *exnBlock = exn->getParent();
+
+ EHSelectorInst *outOfBlockSelector = 0;
+ for (Instruction::use_iterator
+ ui = exn->use_begin(), ue = exn->use_end(); ui != ue; ++ui) {
+ EHSelectorInst *sel = dyn_cast<EHSelectorInst>(*ui);
+ if (!sel) continue;
+
+ // Immediately accept an eh.selector in the same block as the
+ // excepton call.
+ if (sel->getParent() == exnBlock) return sel;
+
+ // Otherwise, use the first selector we see.
+ if (!outOfBlockSelector) outOfBlockSelector = sel;
+ }
+
+ return outOfBlockSelector;
+}
+
+/// [LIBUNWIND] Find the (possibly absent) call to @llvm.eh.selector
+/// in the given landing pad. In principle, llvm.eh.exception is
+/// required to be in the landing pad; in practice, SplitCriticalEdge
+/// can break that invariant, and then inlining can break it further.
+/// There's a real need for a reliable solution here, but until that
+/// happens, we have some fragile workarounds here.
+static EHSelectorInst *findSelectorForLandingPad(BasicBlock *lpad) {
+ // Look for an exception call in the actual landing pad.
+ EHExceptionInst *exn = findExceptionInBlock(lpad);
+ if (exn) return findSelectorForException(exn);
+
+ // Okay, if that failed, look for one in an obvious successor. If
+ // we find one, we'll fix the IR by moving things back to the
+ // landing pad.
+
+ bool dominates = true; // does the lpad dominate the exn call
+ BasicBlock *nonDominated = 0; // if not, the first non-dominated block
+ BasicBlock *lastDominated = 0; // and the block which branched to it
+
+ BasicBlock *exnBlock = lpad;
+
+ // We need to protect against lpads that lead into infinite loops.
+ SmallPtrSet<BasicBlock*,4> visited;
+ visited.insert(exnBlock);
+
+ do {
+ // We're not going to apply this hack to anything more complicated
+ // than a series of unconditional branches, so if the block
+ // doesn't terminate in an unconditional branch, just fail. More
+ // complicated cases can arise when, say, sinking a call into a
+ // split unwind edge and then inlining it; but that can do almost
+ // *anything* to the CFG, including leaving the selector
+ // completely unreachable. The only way to fix that properly is
+ // to (1) prohibit transforms which move the exception or selector
+ // values away from the landing pad, e.g. by producing them with
+ // instructions that are pinned to an edge like a phi, or
+ // producing them with not-really-instructions, and (2) making
+ // transforms which split edges deal with that.
+ BranchInst *branch = dyn_cast<BranchInst>(&exnBlock->back());
+ if (!branch || branch->isConditional()) return 0;
+
+ BasicBlock *successor = branch->getSuccessor(0);
+
+ // Fail if we found an infinite loop.
+ if (!visited.insert(successor)) return 0;
+
+ // If the successor isn't dominated by exnBlock:
+ if (!successor->getSinglePredecessor()) {
+ // We don't want to have to deal with threading the exception
+ // through multiple levels of phi, so give up if we've already
+ // followed a non-dominating edge.
+ if (!dominates) return 0;
+
+ // Otherwise, remember this as a non-dominating edge.
+ dominates = false;
+ nonDominated = successor;
+ lastDominated = exnBlock;
+ }
+
+ exnBlock = successor;
+
+ // Can we stop here?
+ exn = findExceptionInBlock(exnBlock);
+ } while (!exn);
+
+ // Look for a selector call for the exception we found.
+ EHSelectorInst *selector = findSelectorForException(exn);
+ if (!selector) return 0;
+
+ // The easy case is when the landing pad still dominates the
+ // exception call, in which case we can just move both calls back to
+ // the landing pad.
+ if (dominates) {
+ selector->moveBefore(lpad->getFirstNonPHI());
+ exn->moveBefore(selector);
+ return selector;
+ }
+
+ // Otherwise, we have to split at the first non-dominating block.
+ // The CFG looks basically like this:
+ // lpad:
+ // phis_0
+ // insnsAndBranches_1
+ // br label %nonDominated
+ // nonDominated:
+ // phis_2
+ // insns_3
+ // %exn = call i8* @llvm.eh.exception()
+ // insnsAndBranches_4
+ // %selector = call @llvm.eh.selector(i8* %exn, ...
+ // We need to turn this into:
+ // lpad:
+ // phis_0
+ // %exn0 = call i8* @llvm.eh.exception()
+ // %selector0 = call @llvm.eh.selector(i8* %exn0, ...
+ // insnsAndBranches_1
+ // br label %split // from lastDominated
+ // nonDominated:
+ // phis_2 (without edge from lastDominated)
+ // %exn1 = call i8* @llvm.eh.exception()
+ // %selector1 = call i8* @llvm.eh.selector(i8* %exn1, ...
+ // br label %split
+ // split:
+ // phis_2 (edge from lastDominated, edge from split)
+ // %exn = phi ...
+ // %selector = phi ...
+ // insns_3
+ // insnsAndBranches_4
+
+ assert(nonDominated);
+ assert(lastDominated);
+
+ // First, make clones of the intrinsics to go in lpad.
+ EHExceptionInst *lpadExn = cast<EHExceptionInst>(exn->clone());
+ EHSelectorInst *lpadSelector = cast<EHSelectorInst>(selector->clone());
+ lpadSelector->setArgOperand(0, lpadExn);
+ lpadSelector->insertBefore(lpad->getFirstNonPHI());
+ lpadExn->insertBefore(lpadSelector);
+
+ // Split the non-dominated block.
+ BasicBlock *split =
+ nonDominated->splitBasicBlock(nonDominated->getFirstNonPHI(),
+ nonDominated->getName() + ".lpad-fix");
+
+ // Redirect the last dominated branch there.
+ cast<BranchInst>(lastDominated->back()).setSuccessor(0, split);
+
+ // Move the existing intrinsics to the end of the old block.
+ selector->moveBefore(&nonDominated->back());
+ exn->moveBefore(selector);
+
+ Instruction *splitIP = &split->front();
+
+ // For all the phis in nonDominated, make a new phi in split to join
+ // that phi with the edge from lastDominated.
+ for (BasicBlock::iterator
+ i = nonDominated->begin(), e = nonDominated->end(); i != e; ++i) {
+ PHINode *phi = dyn_cast<PHINode>(i);
+ if (!phi) break;
+
+ PHINode *splitPhi = PHINode::Create(phi->getType(), 2, phi->getName(),
+ splitIP);
+ phi->replaceAllUsesWith(splitPhi);
+ splitPhi->addIncoming(phi, nonDominated);
+ splitPhi->addIncoming(phi->removeIncomingValue(lastDominated),
+ lastDominated);
+ }
+
+ // Make new phis for the exception and selector.
+ PHINode *exnPhi = PHINode::Create(exn->getType(), 2, "", splitIP);
+ exn->replaceAllUsesWith(exnPhi);
+ selector->setArgOperand(0, exn); // except for this use
+ exnPhi->addIncoming(exn, nonDominated);
+ exnPhi->addIncoming(lpadExn, lastDominated);
+
+ PHINode *selectorPhi = PHINode::Create(selector->getType(), 2, "", splitIP);
+ selector->replaceAllUsesWith(selectorPhi);
+ selectorPhi->addIncoming(selector, nonDominated);
+ selectorPhi->addIncoming(lpadSelector, lastDominated);
+
+ return lpadSelector;
+}
+
+namespace {
+ /// A class for recording information about inlining through an invoke.
+ class InvokeInliningInfo {
+ BasicBlock *OuterUnwindDest;
+ EHSelectorInst *OuterSelector;
+ BasicBlock *InnerUnwindDest;
+ PHINode *InnerExceptionPHI;
+ PHINode *InnerSelectorPHI;
+ SmallVector<Value*, 8> UnwindDestPHIValues;
+
+ public:
+ InvokeInliningInfo(InvokeInst *II) :
+ OuterUnwindDest(II->getUnwindDest()), OuterSelector(0),
+ InnerUnwindDest(0), InnerExceptionPHI(0), InnerSelectorPHI(0) {
+
+ // If there are PHI nodes in the unwind destination block, we
+ // need to keep track of which values came into them from the
+ // invoke before removing the edge from this block.
+ llvm::BasicBlock *invokeBB = II->getParent();
+ for (BasicBlock::iterator I = OuterUnwindDest->begin();
+ isa<PHINode>(I); ++I) {
+ // Save the value to use for this edge.
+ PHINode *phi = cast<PHINode>(I);
+ UnwindDestPHIValues.push_back(phi->getIncomingValueForBlock(invokeBB));
+ }
+ }
+
+ /// The outer unwind destination is the target of unwind edges
+ /// introduced for calls within the inlined function.
+ BasicBlock *getOuterUnwindDest() const {
+ return OuterUnwindDest;
+ }
+
+ EHSelectorInst *getOuterSelector() {
+ if (!OuterSelector)
+ OuterSelector = findSelectorForLandingPad(OuterUnwindDest);
+ return OuterSelector;
+ }
+
+ BasicBlock *getInnerUnwindDest();
+
+ bool forwardEHResume(CallInst *call, BasicBlock *src);
+
+ /// Add incoming-PHI values to the unwind destination block for
+ /// the given basic block, using the values for the original
+ /// invoke's source block.
+ void addIncomingPHIValuesFor(BasicBlock *BB) const {
+ addIncomingPHIValuesForInto(BB, OuterUnwindDest);
+ }
+
+ void addIncomingPHIValuesForInto(BasicBlock *src, BasicBlock *dest) const {
+ BasicBlock::iterator I = dest->begin();
+ for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
+ PHINode *phi = cast<PHINode>(I);
+ phi->addIncoming(UnwindDestPHIValues[i], src);
+ }
+ }
+ };
+}
+
+/// Get or create a target for the branch out of rewritten calls to
+/// llvm.eh.resume.
+BasicBlock *InvokeInliningInfo::getInnerUnwindDest() {
+ if (InnerUnwindDest) return InnerUnwindDest;
+
+ // Find and hoist the llvm.eh.exception and llvm.eh.selector calls
+ // in the outer landing pad to immediately following the phis.
+ EHSelectorInst *selector = getOuterSelector();
+ if (!selector) return 0;
+
+ // The call to llvm.eh.exception *must* be in the landing pad.
+ Instruction *exn = cast<Instruction>(selector->getArgOperand(0));
+ assert(exn->getParent() == OuterUnwindDest);
+
+ // TODO: recognize when we've already done this, so that we don't
+ // get a linear number of these when inlining calls into lots of
+ // invokes with the same landing pad.
+
+ // Do the hoisting.
+ Instruction *splitPoint = exn->getParent()->getFirstNonPHI();
+ assert(splitPoint != selector && "selector-on-exception dominance broken!");
+ if (splitPoint == exn) {
+ selector->removeFromParent();
+ selector->insertAfter(exn);
+ splitPoint = selector->getNextNode();
+ } else {
+ exn->moveBefore(splitPoint);
+ selector->moveBefore(splitPoint);
+ }
+
+ // Split the landing pad.
+ InnerUnwindDest = OuterUnwindDest->splitBasicBlock(splitPoint,
+ OuterUnwindDest->getName() + ".body");
+
+ // The number of incoming edges we expect to the inner landing pad.
+ const unsigned phiCapacity = 2;
+
+ // Create corresponding new phis for all the phis in the outer landing pad.
+ BasicBlock::iterator insertPoint = InnerUnwindDest->begin();
+ BasicBlock::iterator I = OuterUnwindDest->begin();
+ for (unsigned i = 0, e = UnwindDestPHIValues.size(); i != e; ++i, ++I) {
+ PHINode *outerPhi = cast<PHINode>(I);
+ PHINode *innerPhi = PHINode::Create(outerPhi->getType(), phiCapacity,
+ outerPhi->getName() + ".lpad-body",
+ insertPoint);
+ outerPhi->replaceAllUsesWith(innerPhi);
+ innerPhi->addIncoming(outerPhi, OuterUnwindDest);
+ }
+
+ // Create a phi for the exception value...
+ InnerExceptionPHI = PHINode::Create(exn->getType(), phiCapacity,
+ "exn.lpad-body", insertPoint);
+ exn->replaceAllUsesWith(InnerExceptionPHI);
+ selector->setArgOperand(0, exn); // restore this use
+ InnerExceptionPHI->addIncoming(exn, OuterUnwindDest);
+
+ // ...and the selector.
+ InnerSelectorPHI = PHINode::Create(selector->getType(), phiCapacity,
+ "selector.lpad-body", insertPoint);
+ selector->replaceAllUsesWith(InnerSelectorPHI);
+ InnerSelectorPHI->addIncoming(selector, OuterUnwindDest);
+
+ // All done.
+ return InnerUnwindDest;
+}
+
+/// [LIBUNWIND] Try to forward the given call, which logically occurs
+/// at the end of the given block, as a branch to the inner unwind
+/// block. Returns true if the call was forwarded.
+bool InvokeInliningInfo::forwardEHResume(CallInst *call, BasicBlock *src) {
+ // First, check whether this is a call to the intrinsic.
+ Function *fn = dyn_cast<Function>(call->getCalledValue());
+ if (!fn || fn->getName() != "llvm.eh.resume")
+ return false;
+
+ // At this point, we need to return true on all paths, because
+ // otherwise we'll construct an invoke of the intrinsic, which is
+ // not well-formed.
+
+ // Try to find or make an inner unwind dest, which will fail if we
+ // can't find a selector call for the outer unwind dest.
+ BasicBlock *dest = getInnerUnwindDest();
+ bool hasSelector = (dest != 0);
+
+ // If we failed, just use the outer unwind dest, dropping the
+ // exception and selector on the floor.
+ if (!hasSelector)
+ dest = OuterUnwindDest;
+
+ // Make a branch.
+ BranchInst::Create(dest, src);
+
+ // Update the phis in the destination. They were inserted in an
+ // order which makes this work.
+ addIncomingPHIValuesForInto(src, dest);
+
+ if (hasSelector) {
+ InnerExceptionPHI->addIncoming(call->getArgOperand(0), src);
+ InnerSelectorPHI->addIncoming(call->getArgOperand(1), src);
+ }
+
+ return true;
}
-bool llvm::InlineFunction(InvokeInst *II, CallGraph *CG, const TargetData *TD) {
- return InlineFunction(CallSite(II), CG, TD);
+
+/// [LIBUNWIND] Check whether this selector is "only cleanups":
+/// call i32 @llvm.eh.selector(blah, blah, i32 0)
+static bool isCleanupOnlySelector(EHSelectorInst *selector) {
+ if (selector->getNumArgOperands() != 3) return false;
+ ConstantInt *val = dyn_cast<ConstantInt>(selector->getArgOperand(2));
+ return (val && val->isZero());
}
+/// HandleCallsInBlockInlinedThroughInvoke - When we inline a basic block into
+/// an invoke, we have to turn all of the calls that can throw into
+/// invokes. This function analyze BB to see if there are any calls, and if so,
+/// it rewrites them to be invokes that jump to InvokeDest and fills in the PHI
+/// nodes in that block with the values specified in InvokeDestPHIValues.
+///
+/// Returns true to indicate that the next block should be skipped.
+static bool HandleCallsInBlockInlinedThroughInvoke(BasicBlock *BB,
+ InvokeInliningInfo &Invoke) {
+ for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ) {
+ Instruction *I = BBI++;
+
+ // We only need to check for function calls: inlined invoke
+ // instructions require no special handling.
+ CallInst *CI = dyn_cast<CallInst>(I);
+ if (CI == 0) continue;
+
+ // LIBUNWIND: merge selector instructions.
+ if (EHSelectorInst *Inner = dyn_cast<EHSelectorInst>(CI)) {
+ EHSelectorInst *Outer = Invoke.getOuterSelector();
+ if (!Outer) continue;
+
+ bool innerIsOnlyCleanup = isCleanupOnlySelector(Inner);
+ bool outerIsOnlyCleanup = isCleanupOnlySelector(Outer);
+
+ // If both selectors contain only cleanups, we don't need to do
+ // anything. TODO: this is really just a very specific instance
+ // of a much more general optimization.
+ if (innerIsOnlyCleanup && outerIsOnlyCleanup) continue;
+
+ // Otherwise, we just append the outer selector to the inner selector.
+ SmallVector<Value*, 16> NewSelector;
+ for (unsigned i = 0, e = Inner->getNumArgOperands(); i != e; ++i)
+ NewSelector.push_back(Inner->getArgOperand(i));
+ for (unsigned i = 2, e = Outer->getNumArgOperands(); i != e; ++i)
+ NewSelector.push_back(Outer->getArgOperand(i));
+
+ CallInst *NewInner =
+ IRBuilder<>(Inner).CreateCall(Inner->getCalledValue(),
+ NewSelector.begin(),
+ NewSelector.end());
+ // No need to copy attributes, calling convention, etc.
+ NewInner->takeName(Inner);
+ Inner->replaceAllUsesWith(NewInner);
+ Inner->eraseFromParent();
+ continue;
+ }
+
+ // If this call cannot unwind, don't convert it to an invoke.
+ if (CI->doesNotThrow())
+ continue;
+
+ // Convert this function call into an invoke instruction.
+ // First, split the basic block.
+ BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
+
+ // Delete the unconditional branch inserted by splitBasicBlock
+ BB->getInstList().pop_back();
+
+ // LIBUNWIND: If this is a call to @llvm.eh.resume, just branch
+ // directly to the new landing pad.
+ if (Invoke.forwardEHResume(CI, BB)) {
+ // TODO: 'Split' is now unreachable; clean it up.
+
+ // We want to leave the original call intact so that the call
+ // graph and other structures won't get misled. We also have to
+ // avoid processing the next block, or we'll iterate here forever.
+ return true;
+ }
+
+ // Otherwise, create the new invoke instruction.
+ ImmutableCallSite CS(CI);
+ SmallVector<Value*, 8> InvokeArgs(CS.arg_begin(), CS.arg_end());
+ InvokeInst *II =
+ InvokeInst::Create(CI->getCalledValue(), Split,
+ Invoke.getOuterUnwindDest(),
+ InvokeArgs.begin(), InvokeArgs.end(),
+ CI->getName(), BB);
+ II->setCallingConv(CI->getCallingConv());
+ II->setAttributes(CI->getAttributes());
+
+ // Make sure that anything using the call now uses the invoke! This also
+ // updates the CallGraph if present, because it uses a WeakVH.
+ CI->replaceAllUsesWith(II);
+
+ Split->getInstList().pop_front(); // Delete the original call
+
+ // Update any PHI nodes in the exceptional block to indicate that
+ // there is now a new entry in them.
+ Invoke.addIncomingPHIValuesFor(BB);
+ return false;
+ }
+
+ return false;
+}
+
+
/// HandleInlinedInvoke - If we inlined an invoke site, we need to convert calls
/// in the body of the inlined function into invokes and turn unwind
/// instructions into branches to the invoke unwind dest.
/// block of the inlined code (the last block is the end of the function),
/// and InlineCodeInfo is information about the code that got inlined.
static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock,
- ClonedCodeInfo &InlinedCodeInfo,
- CallGraph *CG) {
+ ClonedCodeInfo &InlinedCodeInfo) {
BasicBlock *InvokeDest = II->getUnwindDest();
- std::vector<Value*> InvokeDestPHIValues;
-
- // If there are PHI nodes in the unwind destination block, we need to
- // keep track of which values came into them from this invoke, then remove
- // the entry for this block.
- BasicBlock *InvokeBlock = II->getParent();
- for (BasicBlock::iterator I = InvokeDest->begin(); isa<PHINode>(I); ++I) {
- PHINode *PN = cast<PHINode>(I);
- // Save the value to use for this edge.
- InvokeDestPHIValues.push_back(PN->getIncomingValueForBlock(InvokeBlock));
- }
Function *Caller = FirstNewBlock->getParent();
// The inlined code is currently at the end of the function, scan from the
// start of the inlined code to its end, checking for stuff we need to
- // rewrite.
- if (InlinedCodeInfo.ContainsCalls || InlinedCodeInfo.ContainsUnwinds) {
- for (Function::iterator BB = FirstNewBlock, E = Caller->end();
- BB != E; ++BB) {
- if (InlinedCodeInfo.ContainsCalls) {
- for (BasicBlock::iterator BBI = BB->begin(), E = BB->end(); BBI != E; ){
- Instruction *I = BBI++;
-
- // We only need to check for function calls: inlined invoke
- // instructions require no special handling.
- if (!isa<CallInst>(I)) continue;
- CallInst *CI = cast<CallInst>(I);
-
- // If this call cannot unwind, don't convert it to an invoke.
- if (CI->doesNotThrow())
- continue;
-
- // Convert this function call into an invoke instruction.
- // First, split the basic block.
- BasicBlock *Split = BB->splitBasicBlock(CI, CI->getName()+".noexc");
-
- // Next, create the new invoke instruction, inserting it at the end
- // of the old basic block.
- SmallVector<Value*, 8> InvokeArgs(CI->op_begin()+1, CI->op_end());
- InvokeInst *II =
- InvokeInst::Create(CI->getCalledValue(), Split, InvokeDest,
- InvokeArgs.begin(), InvokeArgs.end(),
- CI->getName(), BB->getTerminator());
- II->setCallingConv(CI->getCallingConv());
- II->setAttributes(CI->getAttributes());
-
- // Make sure that anything using the call now uses the invoke!
- CI->replaceAllUsesWith(II);
-
- // Update the callgraph.
- if (CG) {
- // We should be able to do this:
- // (*CG)[Caller]->replaceCallSite(CI, II);
- // but that fails if the old call site isn't in the call graph,
- // which, because of LLVM bug 3601, it sometimes isn't.
- CallGraphNode *CGN = (*CG)[Caller];
- for (CallGraphNode::iterator NI = CGN->begin(), NE = CGN->end();
- NI != NE; ++NI) {
- if (NI->first == CI) {
- NI->first = II;
- break;
- }
- }
- }
-
- // Delete the unconditional branch inserted by splitBasicBlock
- BB->getInstList().pop_back();
- Split->getInstList().pop_front(); // Delete the original call
-
- // Update any PHI nodes in the exceptional block to indicate that
- // there is now a new entry in them.
- unsigned i = 0;
- for (BasicBlock::iterator I = InvokeDest->begin();
- isa<PHINode>(I); ++I, ++i) {
- PHINode *PN = cast<PHINode>(I);
- PN->addIncoming(InvokeDestPHIValues[i], BB);
- }
-
- // This basic block is now complete, start scanning the next one.
- break;
- }
- }
+ // rewrite. If the code doesn't have calls or unwinds, we know there is
+ // nothing to rewrite.
+ if (!InlinedCodeInfo.ContainsCalls && !InlinedCodeInfo.ContainsUnwinds) {
+ // Now that everything is happy, we have one final detail. The PHI nodes in
+ // the exception destination block still have entries due to the original
+ // invoke instruction. Eliminate these entries (which might even delete the
+ // PHI node) now.
+ InvokeDest->removePredecessor(II->getParent());
+ return;
+ }
- if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
- // An UnwindInst requires special handling when it gets inlined into an
- // invoke site. Once this happens, we know that the unwind would cause
- // a control transfer to the invoke exception destination, so we can
- // transform it into a direct branch to the exception destination.
- BranchInst::Create(InvokeDest, UI);
-
- // Delete the unwind instruction!
- UI->eraseFromParent();
-
- // Update any PHI nodes in the exceptional block to indicate that
- // there is now a new entry in them.
- unsigned i = 0;
- for (BasicBlock::iterator I = InvokeDest->begin();
- isa<PHINode>(I); ++I, ++i) {
- PHINode *PN = cast<PHINode>(I);
- PN->addIncoming(InvokeDestPHIValues[i], BB);
- }
+ InvokeInliningInfo Invoke(II);
+
+ for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E; ++BB){
+ if (InlinedCodeInfo.ContainsCalls)
+ if (HandleCallsInBlockInlinedThroughInvoke(BB, Invoke)) {
+ // Honor a request to skip the next block. We don't need to
+ // consider UnwindInsts in this case either.
+ ++BB;
+ continue;
}
+
+ if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
+ // An UnwindInst requires special handling when it gets inlined into an
+ // invoke site. Once this happens, we know that the unwind would cause
+ // a control transfer to the invoke exception destination, so we can
+ // transform it into a direct branch to the exception destination.
+ BranchInst::Create(InvokeDest, UI);
+
+ // Delete the unwind instruction!
+ UI->eraseFromParent();
+
+ // Update any PHI nodes in the exceptional block to indicate that
+ // there is now a new entry in them.
+ Invoke.addIncomingPHIValuesFor(BB);
}
}
/// some edges of the callgraph may remain.
static void UpdateCallGraphAfterInlining(CallSite CS,
Function::iterator FirstNewBlock,
- DenseMap<const Value*, Value*> &ValueMap,
- CallGraph &CG) {
+ ValueToValueMapTy &VMap,
+ InlineFunctionInfo &IFI) {
+ CallGraph &CG = *IFI.CG;
const Function *Caller = CS.getInstruction()->getParent()->getParent();
const Function *Callee = CS.getCalledFunction();
CallGraphNode *CalleeNode = CG[Callee];
}
for (; I != E; ++I) {
- const Instruction *OrigCall = I->first.getInstruction();
+ const Value *OrigCall = I->first;
- DenseMap<const Value*, Value*>::iterator VMI = ValueMap.find(OrigCall);
+ ValueToValueMapTy::iterator VMI = VMap.find(OrigCall);
// Only copy the edge if the call was inlined!
- if (VMI != ValueMap.end() && VMI->second) {
- // If the call was inlined, but then constant folded, there is no edge to
- // add. Check for this case.
- if (Instruction *NewCall = dyn_cast<Instruction>(VMI->second))
- CallerNode->addCalledFunction(CallSite::get(NewCall), I->second);
- }
+ if (VMI == VMap.end() || VMI->second == 0)
+ continue;
+
+ // If the call was inlined, but then constant folded, there is no edge to
+ // add. Check for this case.
+ Instruction *NewCall = dyn_cast<Instruction>(VMI->second);
+ if (NewCall == 0) continue;
+
+ // Remember that this call site got inlined for the client of
+ // InlineFunction.
+ IFI.InlinedCalls.push_back(NewCall);
+
+ // It's possible that inlining the callsite will cause it to go from an
+ // indirect to a direct call by resolving a function pointer. If this
+ // happens, set the callee of the new call site to a more precise
+ // destination. This can also happen if the call graph node of the caller
+ // was just unnecessarily imprecise.
+ if (I->second->getFunction() == 0)
+ if (Function *F = CallSite(NewCall).getCalledFunction()) {
+ // Indirect call site resolved to direct call.
+ CallerNode->addCalledFunction(CallSite(NewCall), CG[F]);
+
+ continue;
+ }
+
+ CallerNode->addCalledFunction(CallSite(NewCall), I->second);
}
+
// Update the call graph by deleting the edge from Callee to Caller. We must
// do this after the loop above in case Caller and Callee are the same.
CallerNode->removeCallEdgeFor(CS);
}
-/// findFnRegionEndMarker - This is a utility routine that is used by
-/// InlineFunction. Return llvm.dbg.region.end intrinsic that corresponds
-/// to the llvm.dbg.func.start of the function F. Otherwise return NULL.
-static const DbgRegionEndInst *findFnRegionEndMarker(const Function *F) {
-
- GlobalVariable *FnStart = NULL;
- const DbgRegionEndInst *FnEnd = NULL;
- for (Function::const_iterator FI = F->begin(), FE =F->end(); FI != FE; ++FI)
- for (BasicBlock::const_iterator BI = FI->begin(), BE = FI->end(); BI != BE;
- ++BI) {
- if (FnStart == NULL) {
- if (const DbgFuncStartInst *FSI = dyn_cast<DbgFuncStartInst>(BI)) {
- DISubprogram SP(cast<GlobalVariable>(FSI->getSubprogram()));
- assert (SP.isNull() == false && "Invalid llvm.dbg.func.start");
- if (SP.describes(F))
- FnStart = SP.getGV();
- }
- } else {
- if (const DbgRegionEndInst *REI = dyn_cast<DbgRegionEndInst>(BI))
- if (REI->getContext() == FnStart)
- FnEnd = REI;
+/// HandleByValArgument - When inlining a call site that has a byval argument,
+/// we have to make the implicit memcpy explicit by adding it.
+static Value *HandleByValArgument(Value *Arg, Instruction *TheCall,
+ const Function *CalledFunc,
+ InlineFunctionInfo &IFI,
+ unsigned ByValAlignment) {
+ const Type *AggTy = cast<PointerType>(Arg->getType())->getElementType();
+
+ // If the called function is readonly, then it could not mutate the caller's
+ // copy of the byval'd memory. In this case, it is safe to elide the copy and
+ // temporary.
+ if (CalledFunc->onlyReadsMemory()) {
+ // If the byval argument has a specified alignment that is greater than the
+ // passed in pointer, then we either have to round up the input pointer or
+ // give up on this transformation.
+ if (ByValAlignment <= 1) // 0 = unspecified, 1 = no particular alignment.
+ return Arg;
+
+ // If the pointer is already known to be sufficiently aligned, or if we can
+ // round it up to a larger alignment, then we don't need a temporary.
+ if (getOrEnforceKnownAlignment(Arg, ByValAlignment,
+ IFI.TD) >= ByValAlignment)
+ return Arg;
+
+ // Otherwise, we have to make a memcpy to get a safe alignment. This is bad
+ // for code quality, but rarely happens and is required for correctness.
+ }
+
+ LLVMContext &Context = Arg->getContext();
+
+ const Type *VoidPtrTy = Type::getInt8PtrTy(Context);
+
+ // Create the alloca. If we have TargetData, use nice alignment.
+ unsigned Align = 1;
+ if (IFI.TD)
+ Align = IFI.TD->getPrefTypeAlignment(AggTy);
+
+ // If the byval had an alignment specified, we *must* use at least that
+ // alignment, as it is required by the byval argument (and uses of the
+ // pointer inside the callee).
+ Align = std::max(Align, ByValAlignment);
+
+ Function *Caller = TheCall->getParent()->getParent();
+
+ Value *NewAlloca = new AllocaInst(AggTy, 0, Align, Arg->getName(),
+ &*Caller->begin()->begin());
+ // Emit a memcpy.
+ const Type *Tys[3] = {VoidPtrTy, VoidPtrTy, Type::getInt64Ty(Context)};
+ Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
+ Intrinsic::memcpy,
+ Tys, 3);
+ Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
+ Value *SrcCast = new BitCastInst(Arg, VoidPtrTy, "tmp", TheCall);
+
+ Value *Size;
+ if (IFI.TD == 0)
+ Size = ConstantExpr::getSizeOf(AggTy);
+ else
+ Size = ConstantInt::get(Type::getInt64Ty(Context),
+ IFI.TD->getTypeStoreSize(AggTy));
+
+ // Always generate a memcpy of alignment 1 here because we don't know
+ // the alignment of the src pointer. Other optimizations can infer
+ // better alignment.
+ Value *CallArgs[] = {
+ DestCast, SrcCast, Size,
+ ConstantInt::get(Type::getInt32Ty(Context), 1),
+ ConstantInt::getFalse(Context) // isVolatile
+ };
+ IRBuilder<>(TheCall).CreateCall(MemCpyFn, CallArgs, CallArgs+5);
+
+ // Uses of the argument in the function should use our new alloca
+ // instead.
+ return NewAlloca;
+}
+
+// isUsedByLifetimeMarker - Check whether this Value is used by a lifetime
+// intrinsic.
+static bool isUsedByLifetimeMarker(Value *V) {
+ for (Value::use_iterator UI = V->use_begin(), UE = V->use_end(); UI != UE;
+ ++UI) {
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*UI)) {
+ switch (II->getIntrinsicID()) {
+ default: break;
+ case Intrinsic::lifetime_start:
+ case Intrinsic::lifetime_end:
+ return true;
}
}
- return FnEnd;
+ }
+ return false;
+}
+
+// hasLifetimeMarkers - Check whether the given alloca already has
+// lifetime.start or lifetime.end intrinsics.
+static bool hasLifetimeMarkers(AllocaInst *AI) {
+ const Type *Int8PtrTy = Type::getInt8PtrTy(AI->getType()->getContext());
+ if (AI->getType() == Int8PtrTy)
+ return isUsedByLifetimeMarker(AI);
+
+ // Do a scan to find all the casts to i8*.
+ for (Value::use_iterator I = AI->use_begin(), E = AI->use_end(); I != E;
+ ++I) {
+ if (I->getType() != Int8PtrTy) continue;
+ if (I->stripPointerCasts() != AI) continue;
+ if (isUsedByLifetimeMarker(*I))
+ return true;
+ }
+ return false;
}
// InlineFunction - This function inlines the called function into the basic
//
// Note that this only does one level of inlining. For example, if the
// instruction 'call B' is inlined, and 'B' calls 'C', then the call to 'C' now
-// exists in the instruction stream. Similiarly this will inline a recursive
+// exists in the instruction stream. Similarly this will inline a recursive
// function by one level.
//
-bool llvm::InlineFunction(CallSite CS, CallGraph *CG, const TargetData *TD) {
+bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI) {
Instruction *TheCall = CS.getInstruction();
LLVMContext &Context = TheCall->getContext();
assert(TheCall->getParent() && TheCall->getParent()->getParent() &&
"Instruction not in function!");
+ // If IFI has any state in it, zap it before we fill it in.
+ IFI.reset();
+
const Function *CalledFunc = CS.getCalledFunction();
if (CalledFunc == 0 || // Can't inline external function or indirect
CalledFunc->isDeclaration() || // call, or call to a vararg function!
CalledFunc->getFunctionType()->isVarArg()) return false;
-
// If the call to the callee is not a tail call, we must clear the 'tail'
// flags on any calls that we inline.
bool MustClearTailCallFlags =
// Make sure to capture all of the return instructions from the cloned
// function.
- std::vector<ReturnInst*> Returns;
+ SmallVector<ReturnInst*, 8> Returns;
ClonedCodeInfo InlinedFunctionInfo;
Function::iterator FirstNewBlock;
- { // Scope to destroy ValueMap after cloning.
- DenseMap<const Value*, Value*> ValueMap;
+ { // Scope to destroy VMap after cloning.
+ ValueToValueMapTy VMap;
assert(CalledFunc->arg_size() == CS.arg_size() &&
"No varargs calls can be inlined!");
// by them explicit. However, we don't do this if the callee is readonly
// or readnone, because the copy would be unneeded: the callee doesn't
// modify the struct.
- if (CalledFunc->paramHasAttr(ArgNo+1, Attribute::ByVal) &&
- !CalledFunc->onlyReadsMemory()) {
- const Type *AggTy = cast<PointerType>(I->getType())->getElementType();
- const Type *VoidPtrTy = Context.getPointerTypeUnqual(Type::Int8Ty);
-
- // Create the alloca. If we have TargetData, use nice alignment.
- unsigned Align = 1;
- if (TD) Align = TD->getPrefTypeAlignment(AggTy);
- Value *NewAlloca = new AllocaInst(AggTy, 0, Align,
- I->getName(),
- &*Caller->begin()->begin());
- // Emit a memcpy.
- const Type *Tys[] = { Type::Int64Ty };
- Function *MemCpyFn = Intrinsic::getDeclaration(Caller->getParent(),
- Intrinsic::memcpy,
- Tys, 1);
- Value *DestCast = new BitCastInst(NewAlloca, VoidPtrTy, "tmp", TheCall);
- Value *SrcCast = new BitCastInst(*AI, VoidPtrTy, "tmp", TheCall);
-
- Value *Size;
- if (TD == 0)
- Size = Context.getConstantExprSizeOf(AggTy);
- else
- Size = ConstantInt::get(Type::Int64Ty,
- TD->getTypeStoreSize(AggTy));
-
- // Always generate a memcpy of alignment 1 here because we don't know
- // the alignment of the src pointer. Other optimizations can infer
- // better alignment.
- Value *CallArgs[] = {
- DestCast, SrcCast, Size, ConstantInt::get(Type::Int32Ty, 1)
- };
- CallInst *TheMemCpy =
- CallInst::Create(MemCpyFn, CallArgs, CallArgs+4, "", TheCall);
-
- // If we have a call graph, update it.
- if (CG) {
- CallGraphNode *MemCpyCGN = CG->getOrInsertFunction(MemCpyFn);
- CallGraphNode *CallerNode = (*CG)[Caller];
- CallerNode->addCalledFunction(TheMemCpy, MemCpyCGN);
- }
-
- // Uses of the argument in the function should use our new alloca
- // instead.
- ActualArg = NewAlloca;
+ if (CalledFunc->paramHasAttr(ArgNo+1, Attribute::ByVal)) {
+ ActualArg = HandleByValArgument(ActualArg, TheCall, CalledFunc, IFI,
+ CalledFunc->getParamAlignment(ArgNo+1));
+
+ // Calls that we inline may use the new alloca, so we need to clear
+ // their 'tail' flags if HandleByValArgument introduced a new alloca and
+ // the callee has calls.
+ MustClearTailCallFlags |= ActualArg != *AI;
}
- ValueMap[I] = ActualArg;
- }
-
- // Adjust llvm.dbg.region.end. If the CalledFunc has region end
- // marker then clone that marker after next stop point at the
- // call site. The function body cloner does not clone original
- // region end marker from the CalledFunc. This will ensure that
- // inlined function's scope ends at the right place.
- const DbgRegionEndInst *DREI = findFnRegionEndMarker(CalledFunc);
- if (DREI) {
- for (BasicBlock::iterator BI = TheCall,
- BE = TheCall->getParent()->end(); BI != BE; ++BI) {
- if (DbgStopPointInst *DSPI = dyn_cast<DbgStopPointInst>(BI)) {
- if (DbgRegionEndInst *NewDREI =
- dyn_cast<DbgRegionEndInst>(DREI->clone(Context)))
- NewDREI->insertAfter(DSPI);
- break;
- }
- }
+ VMap[I] = ActualArg;
}
// We want the inliner to prune the code as it copies. We would LOVE to
// have no dead or constant instructions leftover after inlining occurs
// (which can happen, e.g., because an argument was constant), but we'll be
// happy with whatever the cloner can do.
- CloneAndPruneFunctionInto(Caller, CalledFunc, ValueMap, Returns, ".i",
- &InlinedFunctionInfo, TD);
+ CloneAndPruneFunctionInto(Caller, CalledFunc, VMap,
+ /*ModuleLevelChanges=*/false, Returns, ".i",
+ &InlinedFunctionInfo, IFI.TD, TheCall);
// Remember the first block that is newly cloned over.
FirstNewBlock = LastBlock; ++FirstNewBlock;
// Update the callgraph if requested.
- if (CG)
- UpdateCallGraphAfterInlining(CS, FirstNewBlock, ValueMap, *CG);
+ if (IFI.CG)
+ UpdateCallGraphAfterInlining(CS, FirstNewBlock, VMap, IFI);
}
// If there are any alloca instructions in the block that used to be the entry
{
BasicBlock::iterator InsertPoint = Caller->begin()->begin();
for (BasicBlock::iterator I = FirstNewBlock->begin(),
- E = FirstNewBlock->end(); I != E; )
- if (AllocaInst *AI = dyn_cast<AllocaInst>(I++)) {
- // If the alloca is now dead, remove it. This often occurs due to code
- // specialization.
- if (AI->use_empty()) {
- AI->eraseFromParent();
- continue;
- }
+ E = FirstNewBlock->end(); I != E; ) {
+ AllocaInst *AI = dyn_cast<AllocaInst>(I++);
+ if (AI == 0) continue;
+
+ // If the alloca is now dead, remove it. This often occurs due to code
+ // specialization.
+ if (AI->use_empty()) {
+ AI->eraseFromParent();
+ continue;
+ }
- if (isa<Constant>(AI->getArraySize())) {
- // Scan for the block of allocas that we can move over, and move them
- // all at once.
- while (isa<AllocaInst>(I) &&
- isa<Constant>(cast<AllocaInst>(I)->getArraySize()))
- ++I;
-
- // Transfer all of the allocas over in a block. Using splice means
- // that the instructions aren't removed from the symbol table, then
- // reinserted.
- Caller->getEntryBlock().getInstList().splice(
- InsertPoint,
- FirstNewBlock->getInstList(),
- AI, I);
- }
+ if (!isa<Constant>(AI->getArraySize()))
+ continue;
+
+ // Keep track of the static allocas that we inline into the caller.
+ IFI.StaticAllocas.push_back(AI);
+
+ // Scan for the block of allocas that we can move over, and move them
+ // all at once.
+ while (isa<AllocaInst>(I) &&
+ isa<Constant>(cast<AllocaInst>(I)->getArraySize())) {
+ IFI.StaticAllocas.push_back(cast<AllocaInst>(I));
+ ++I;
+ }
+
+ // Transfer all of the allocas over in a block. Using splice means
+ // that the instructions aren't removed from the symbol table, then
+ // reinserted.
+ Caller->getEntryBlock().getInstList().splice(InsertPoint,
+ FirstNewBlock->getInstList(),
+ AI, I);
+ }
+ }
+
+ // Leave lifetime markers for the static alloca's, scoping them to the
+ // function we just inlined.
+ if (!IFI.StaticAllocas.empty()) {
+ IRBuilder<> builder(FirstNewBlock->begin());
+ for (unsigned ai = 0, ae = IFI.StaticAllocas.size(); ai != ae; ++ai) {
+ AllocaInst *AI = IFI.StaticAllocas[ai];
+
+ // If the alloca is already scoped to something smaller than the whole
+ // function then there's no need to add redundant, less accurate markers.
+ if (hasLifetimeMarkers(AI))
+ continue;
+
+ builder.CreateLifetimeStart(AI);
+ for (unsigned ri = 0, re = Returns.size(); ri != re; ++ri) {
+ IRBuilder<> builder(Returns[ri]);
+ builder.CreateLifetimeEnd(AI);
}
+ }
}
// If the inlined code contained dynamic alloca instructions, wrap the inlined
if (InlinedFunctionInfo.ContainsDynamicAllocas) {
Module *M = Caller->getParent();
// Get the two intrinsics we care about.
- Constant *StackSave, *StackRestore;
- StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
- StackRestore = Intrinsic::getDeclaration(M, Intrinsic::stackrestore);
-
- // If we are preserving the callgraph, add edges to the stacksave/restore
- // functions for the calls we insert.
- CallGraphNode *StackSaveCGN = 0, *StackRestoreCGN = 0, *CallerNode = 0;
- if (CG) {
- // We know that StackSave/StackRestore are Function*'s, because they are
- // intrinsics which must have the right types.
- StackSaveCGN = CG->getOrInsertFunction(cast<Function>(StackSave));
- StackRestoreCGN = CG->getOrInsertFunction(cast<Function>(StackRestore));
- CallerNode = (*CG)[Caller];
- }
+ Function *StackSave = Intrinsic::getDeclaration(M, Intrinsic::stacksave);
+ Function *StackRestore=Intrinsic::getDeclaration(M,Intrinsic::stackrestore);
// Insert the llvm.stacksave.
- CallInst *SavedPtr = CallInst::Create(StackSave, "savedstack",
- FirstNewBlock->begin());
- if (CG) CallerNode->addCalledFunction(SavedPtr, StackSaveCGN);
+ CallInst *SavedPtr = IRBuilder<>(FirstNewBlock, FirstNewBlock->begin())
+ .CreateCall(StackSave, "savedstack");
// Insert a call to llvm.stackrestore before any return instructions in the
// inlined function.
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
- CallInst *CI = CallInst::Create(StackRestore, SavedPtr, "", Returns[i]);
- if (CG) CallerNode->addCalledFunction(CI, StackRestoreCGN);
+ IRBuilder<>(Returns[i]).CreateCall(StackRestore, SavedPtr);
}
// Count the number of StackRestore calls we insert.
for (Function::iterator BB = FirstNewBlock, E = Caller->end();
BB != E; ++BB)
if (UnwindInst *UI = dyn_cast<UnwindInst>(BB->getTerminator())) {
- CallInst::Create(StackRestore, SavedPtr, "", UI);
+ IRBuilder<>(UI).CreateCall(StackRestore, SavedPtr);
++NumStackRestores;
}
}
BB != E; ++BB) {
TerminatorInst *Term = BB->getTerminator();
if (isa<UnwindInst>(Term)) {
- new UnreachableInst(Term);
+ new UnreachableInst(Context, Term);
BB->getInstList().erase(Term);
}
}
// any inlined 'unwind' instructions into branches to the invoke exception
// destination, and call instructions into invoke instructions.
if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall))
- HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo, CG);
+ HandleInlinedInvoke(II, FirstNewBlock, InlinedFunctionInfo);
// If we cloned in _exactly one_ basic block, and if that block ends in a
// return instruction, we splice the body of the inlined callee directly into
if (!TheCall->use_empty()) {
ReturnInst *R = Returns[0];
if (TheCall == R->getReturnValue())
- TheCall->replaceAllUsesWith(Context.getUndef(TheCall->getType()));
+ TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
else
TheCall->replaceAllUsesWith(R->getReturnValue());
}
// any users of the original call/invoke instruction.
const Type *RTy = CalledFunc->getReturnType();
+ PHINode *PHI = 0;
if (Returns.size() > 1) {
// The PHI node should go at the front of the new basic block to merge all
// possible incoming values.
- PHINode *PHI = 0;
if (!TheCall->use_empty()) {
- PHI = PHINode::Create(RTy, TheCall->getName(),
+ PHI = PHINode::Create(RTy, Returns.size(), TheCall->getName(),
AfterCallBB->begin());
// Anything that used the result of the function call should now use the
// PHI node as their operand.
}
}
+
// Add a branch to the merge points and remove return instructions.
for (unsigned i = 0, e = Returns.size(); i != e; ++i) {
ReturnInst *RI = Returns[i];
// using the return value of the call with the computed value.
if (!TheCall->use_empty()) {
if (TheCall == Returns[0]->getReturnValue())
- TheCall->replaceAllUsesWith(Context.getUndef(TheCall->getType()));
+ TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
else
TheCall->replaceAllUsesWith(Returns[0]->getReturnValue());
}
} else if (!TheCall->use_empty()) {
// No returns, but something is using the return value of the call. Just
// nuke the result.
- TheCall->replaceAllUsesWith(Context.getUndef(TheCall->getType()));
+ TheCall->replaceAllUsesWith(UndefValue::get(TheCall->getType()));
}
// Since we are now done with the Call/Invoke, we can delete it.
// Now we can remove the CalleeEntry block, which is now empty.
Caller->getBasicBlockList().erase(CalleeEntry);
+ // If we inserted a phi node, check to see if it has a single value (e.g. all
+ // the entries are the same or undef). If so, remove the PHI so it doesn't
+ // block other optimizations.
+ if (PHI)
+ if (Value *V = SimplifyInstruction(PHI, IFI.TD)) {
+ PHI->replaceAllUsesWith(V);
+ PHI->eraseFromParent();
+ }
+
return true;
}
projects / oota-llvm.git / blobdiff