return const_cast<BasicBlock*>(this)->getFirstNonPHIOrDbg();
}
- // Same as above, but also skip lifetime intrinsics.
- Instruction* getFirstNonPHIOrDbgOrLifetime();
- const Instruction* getFirstNonPHIOrDbgOrLifetime() const {
- return const_cast<BasicBlock*>(this)->getFirstNonPHIOrDbgOrLifetime();
- }
-
/// removeFromParent - This method unlinks 'this' from the containing
/// function, but does not delete it.
///
/// TryToSimplifyUncondBranchFromEmptyBlock - BB is known to contain an
/// unconditional branch, and contains no instructions other than PHI nodes,
-/// potential side-effect free intrinsics and the branch. If possible,
-/// eliminate BB by rewriting all the predecessors to branch to the successor
-/// block and return true. If we can't transform, return false.
+/// potential debug intrinsics and the branch. If possible, eliminate BB by
+/// rewriting all the predecessors to branch to the successor block and return
+/// true. If we can't transform, return false.
bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB) {
assert(BB != &BB->getParent()->getEntryBlock() &&
"TryToSimplifyUncondBranchFromEmptyBlock called on entry block!");
}
}
- if (Succ->getSinglePredecessor()) {
- // BB is the only predecessor of Succ, so Succ will end up with exactly
- // the same predecessors BB had.
-
- // Copy over any phi, debug or lifetime instruction.
- BB->getTerminator()->eraseFromParent();
- Succ->getInstList().splice(Succ->begin(), BB->getInstList());
- } else {
- while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
+ while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
+ if (Succ->getSinglePredecessor()) {
+ // BB is the only predecessor of Succ, so Succ will end up with exactly
+ // the same predecessors BB had.
+ Succ->getInstList().splice(Succ->begin(),
+ BB->getInstList(), BB->begin());
+ } else {
// We explicitly check for such uses in CanPropagatePredecessorsForPHIs.
assert(PN->use_empty() && "There shouldn't be any uses here!");
PN->eraseFromParent();
BasicBlock *BB = BI->getParent();
// If the Terminator is the only non-phi instruction, simplify the block.
- BasicBlock::iterator I = BB->getFirstNonPHIOrDbgOrLifetime();
+ BasicBlock::iterator I = BB->getFirstNonPHIOrDbg();
if (I->isTerminator() && BB != &BB->getParent()->getEntryBlock() &&
TryToSimplifyUncondBranchFromEmptyBlock(BB))
return true;
return &*i;
}
-Instruction* BasicBlock::getFirstNonPHIOrDbgOrLifetime() {
- // All valid basic blocks should have a terminator,
- // which is not a PHINode. If we have an invalid basic
- // block we'll get an assertion failure when dereferencing
- // a past-the-end iterator.
- BasicBlock::iterator i = begin();
- for (;; ++i) {
- if (isa<PHINode>(i) || isa<DbgInfoIntrinsic>(i))
- continue;
-
- const IntrinsicInst *II = dyn_cast<IntrinsicInst>(i);
- if (!II)
- break;
- if (II->getIntrinsicID() != Intrinsic::lifetime_start &&
- II->getIntrinsicID() != Intrinsic::lifetime_end)
- break;
- }
- return &*i;
-}
-
void BasicBlock::dropAllReferences() {
for(iterator I = begin(), E = end(); I != E; ++I)
I->dropAllReferences();
+++ /dev/null
-; RUN: opt < %s -simplifycfg -S | FileCheck %s
-
-; Test that a lifetime intrinsic doesn't prevent us from simplifying this.
-
-; CHECK: foo
-; CHECK: entry:
-; CHECK-NOT: bb0:
-; CHECK-NOT: bb1:
-; CHECK: ret
-define void @foo(i1 %x) {
-entry:
- %a = alloca i8
- call void @llvm.lifetime.start(i64 -1, i8* %a) nounwind
- br i1 %x, label %bb0, label %bb1
-
-bb0:
- call void @llvm.lifetime.end(i64 -1, i8* %a) nounwind
- br label %bb1
-
-bb1:
- call void @f()
- ret void
-}
-
-declare void @f()
-
-declare void @llvm.lifetime.start(i64, i8* nocapture) nounwind
-
-declare void @llvm.lifetime.end(i64, i8* nocapture) nounwind