[llvm-commits] [llvm] r51668 - in /llvm/trunk: lib/Transforms/Scalar/ADCE.cpp test/Transforms/ADCE/2003-12-19-MergeReturn.ll test/Transforms/ADCE/dead-phi-edge.ll
Owen Anderson
resistor at mac.com
Thu May 29 01:45:13 PDT 2008
Author: resistor
Date: Thu May 29 03:45:13 2008
New Revision: 51668
URL: http://llvm.org/viewvc/llvm-project?rev=51668&view=rev
Log:
Replace the old ADCE implementation with a new one that more simply solves
the one case that ADCE catches that normal DCE doesn't: non-induction variable
loop computations.
This implementation handles this problem without using postdominators.
Removed:
llvm/trunk/test/Transforms/ADCE/2003-12-19-MergeReturn.ll
llvm/trunk/test/Transforms/ADCE/dead-phi-edge.ll
Modified:
llvm/trunk/lib/Transforms/Scalar/ADCE.cpp
Modified: llvm/trunk/lib/Transforms/Scalar/ADCE.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/ADCE.cpp?rev=51668&r1=51667&r2=51668&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/ADCE.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/ADCE.cpp Thu May 29 03:45:13 2008
@@ -1,4 +1,4 @@
-//===- ADCE.cpp - Code to perform aggressive dead code elimination --------===//
+//===- DCE.cpp - Code to perform dead code elimination --------------------===//
//
// The LLVM Compiler Infrastructure
//
@@ -7,481 +7,86 @@
//
//===----------------------------------------------------------------------===//
//
-// This file implements "aggressive" dead code elimination. ADCE is DCe where
-// values are assumed to be dead until proven otherwise. This is similar to
-// SCCP, except applied to the liveness of values.
+// This file implements the Aggressive Dead Code Elimination pass. This pass
+// optimistically assumes that all instructions are dead until proven otherwise,
+// allowing it to eliminate dead computations that other DCE passes do not
+// catch, particularly involving loop computations.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "adce"
#include "llvm/Transforms/Scalar.h"
-#include "llvm/Constants.h"
#include "llvm/Instructions.h"
-#include "llvm/Analysis/AliasAnalysis.h"
-#include "llvm/Analysis/PostDominators.h"
-#include "llvm/Support/CFG.h"
-#include "llvm/Transforms/Utils/BasicBlockUtils.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
-#include "llvm/Support/Debug.h"
-#include "llvm/ADT/DepthFirstIterator.h"
-#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/Statistic.h"
-#include "llvm/ADT/STLExtras.h"
+#include "llvm/Pass.h"
#include "llvm/Support/Compiler.h"
-#include <algorithm>
+#include "llvm/Support/InstIterator.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/SmallPtrSet.h"
+
using namespace llvm;
-STATISTIC(NumBlockRemoved, "Number of basic blocks removed");
-STATISTIC(NumInstRemoved , "Number of instructions removed");
-STATISTIC(NumCallRemoved , "Number of calls removed");
+STATISTIC(NumRemoved, "Number of instructions removed");
namespace {
-//===----------------------------------------------------------------------===//
-// ADCE Class
-//
-// This class does all of the work of Aggressive Dead Code Elimination.
-// It's public interface consists of a constructor and a doADCE() method.
-//
-class VISIBILITY_HIDDEN ADCE : public FunctionPass {
- Function *Func; // The function that we are working on
- std::vector<Instruction*> WorkList; // Instructions that just became live
- std::set<Instruction*> LiveSet; // The set of live instructions
-
- //===--------------------------------------------------------------------===//
- // The public interface for this class
- //
-public:
- static char ID; // Pass identification, replacement for typeid
- ADCE() : FunctionPass((intptr_t)&ID) {}
-
- // Execute the Aggressive Dead Code Elimination Algorithm
- //
- virtual bool runOnFunction(Function &F) {
- Func = &F;
- bool Changed = doADCE();
- assert(WorkList.empty());
- LiveSet.clear();
- return Changed;
- }
- // getAnalysisUsage - We require post dominance frontiers (aka Control
- // Dependence Graph)
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- // We require that all function nodes are unified, because otherwise code
- // can be marked live that wouldn't necessarily be otherwise.
- AU.addRequired<UnifyFunctionExitNodes>();
- AU.addRequired<AliasAnalysis>();
- AU.addRequired<PostDominatorTree>();
- AU.addRequired<PostDominanceFrontier>();
- }
-
-
- //===--------------------------------------------------------------------===//
- // The implementation of this class
- //
-private:
- // doADCE() - Run the Aggressive Dead Code Elimination algorithm, returning
- // true if the function was modified.
- //
- bool doADCE();
-
- void markBlockAlive(BasicBlock *BB);
-
-
- // deleteDeadInstructionsInLiveBlock - Loop over all of the instructions in
- // the specified basic block, deleting ones that are dead according to
- // LiveSet.
- bool deleteDeadInstructionsInLiveBlock(BasicBlock *BB);
-
- TerminatorInst *convertToUnconditionalBranch(TerminatorInst *TI);
-
- inline void markInstructionLive(Instruction *I) {
- if (!LiveSet.insert(I).second) return;
- DOUT << "Insn Live: " << *I;
- WorkList.push_back(I);
- }
-
- inline void markTerminatorLive(const BasicBlock *BB) {
- DOUT << "Terminator Live: " << *BB->getTerminator();
- markInstructionLive(const_cast<TerminatorInst*>(BB->getTerminator()));
- }
-};
-} // End of anonymous namespace
-
-char ADCE::ID = 0;
-static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination");
-
-FunctionPass *llvm::createAggressiveDCEPass() { return new ADCE(); }
-
-void ADCE::markBlockAlive(BasicBlock *BB) {
- // Mark the basic block as being newly ALIVE... and mark all branches that
- // this block is control dependent on as being alive also...
- //
- PostDominanceFrontier &CDG = getAnalysis<PostDominanceFrontier>();
-
- PostDominanceFrontier::const_iterator It = CDG.find(BB);
- if (It != CDG.end()) {
- // Get the blocks that this node is control dependent on...
- const PostDominanceFrontier::DomSetType &CDB = It->second;
- for (PostDominanceFrontier::DomSetType::const_iterator I =
- CDB.begin(), E = CDB.end(); I != E; ++I)
- markTerminatorLive(*I); // Mark all their terminators as live
- }
-
- // If this basic block is live, and it ends in an unconditional branch, then
- // the branch is alive as well...
- if (BranchInst *BI = dyn_cast<BranchInst>(BB->getTerminator()))
- if (BI->isUnconditional())
- markTerminatorLive(BB);
-}
-
-// deleteDeadInstructionsInLiveBlock - Loop over all of the instructions in the
-// specified basic block, deleting ones that are dead according to LiveSet.
-bool ADCE::deleteDeadInstructionsInLiveBlock(BasicBlock *BB) {
- bool Changed = false;
- for (BasicBlock::iterator II = BB->begin(), E = --BB->end(); II != E; ) {
- Instruction *I = II++;
- if (!LiveSet.count(I)) { // Is this instruction alive?
- if (!I->use_empty())
- I->replaceAllUsesWith(UndefValue::get(I->getType()));
-
- // Nope... remove the instruction from it's basic block...
- if (isa<CallInst>(I))
- ++NumCallRemoved;
- else
- ++NumInstRemoved;
- BB->getInstList().erase(I);
- Changed = true;
+ struct VISIBILITY_HIDDEN ADCE : public FunctionPass {
+ static char ID; // Pass identification, replacement for typeid
+ ADCE() : FunctionPass((intptr_t)&ID) {}
+
+ virtual bool runOnFunction(Function& F);
+
+ virtual void getAnalysisUsage(AnalysisUsage& AU) const {
+ AU.setPreservesCFG();
}
- }
- return Changed;
-}
-
-
-/// convertToUnconditionalBranch - Transform this conditional terminator
-/// instruction into an unconditional branch because we don't care which of the
-/// successors it goes to. This eliminate a use of the condition as well.
-///
-TerminatorInst *ADCE::convertToUnconditionalBranch(TerminatorInst *TI) {
- BranchInst *NB = BranchInst::Create(TI->getSuccessor(0), TI);
- BasicBlock *BB = TI->getParent();
-
- // Remove entries from PHI nodes to avoid confusing ourself later...
- for (unsigned i = 1, e = TI->getNumSuccessors(); i != e; ++i)
- TI->getSuccessor(i)->removePredecessor(BB);
-
- // Delete the old branch itself...
- BB->getInstList().erase(TI);
- return NB;
+
+ };
}
+char ADCE::ID = 0;
+static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination");
-// doADCE() - Run the Aggressive Dead Code Elimination algorithm, returning
-// true if the function was modified.
-//
-bool ADCE::doADCE() {
- bool MadeChanges = false;
-
- AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
-
- // Iterate over all of the instructions in the function, eliminating trivially
- // dead instructions, and marking instructions live that are known to be
- // needed. Perform the walk in depth first order so that we avoid marking any
- // instructions live in basic blocks that are unreachable. These blocks will
- // be eliminated later, along with the instructions inside.
- //
- std::set<BasicBlock*> ReachableBBs;
- std::vector<BasicBlock*> Stack;
- Stack.push_back(&Func->getEntryBlock());
+bool ADCE::runOnFunction(Function& F) {
+ SmallPtrSet<Instruction*, 32> alive;
+ std::vector<Instruction*> worklist;
- while (!Stack.empty()) {
- BasicBlock* BB = Stack.back();
- if (ReachableBBs.count(BB)) {
- Stack.pop_back();
- continue;
- } else {
- ReachableBBs.insert(BB);
- }
-
- for (BasicBlock::iterator II = BB->begin(), EI = BB->end(); II != EI; ) {
- Instruction *I = II++;
- if (CallInst *CI = dyn_cast<CallInst>(I)) {
- if (AA.onlyReadsMemory(CI)) {
- if (CI->use_empty()) {
- BB->getInstList().erase(CI);
- ++NumCallRemoved;
- }
- } else {
- markInstructionLive(I);
- }
- } else if (I->mayWriteToMemory() || isa<ReturnInst>(I) ||
- isa<UnwindInst>(I) || isa<UnreachableInst>(I)) {
- // FIXME: Unreachable instructions should not be marked intrinsically
- // live here.
- markInstructionLive(I);
- } else if (isInstructionTriviallyDead(I)) {
- // Remove the instruction from it's basic block...
- BB->getInstList().erase(I);
- ++NumInstRemoved;
- }
+ // Collect the set of "root" instructions that are known live.
+ for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
+ if (isa<TerminatorInst>(I.getInstructionIterator()) ||
+ I->mayWriteToMemory()) {
+ alive.insert(I.getInstructionIterator());
+ worklist.push_back(I.getInstructionIterator());
}
- for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI) {
- // Back edges (as opposed to cross edges) indicate loops, so implicitly
- // mark them live.
- if (std::find(Stack.begin(), Stack.end(), *SI) != Stack.end())
- markInstructionLive(BB->getTerminator());
- if (!ReachableBBs.count(*SI))
- Stack.push_back(*SI);
- }
- }
-
- // Check to ensure we have an exit node for this CFG. If we don't, we won't
- // have any post-dominance information, thus we cannot perform our
- // transformations safely.
- //
- PostDominatorTree &DT = getAnalysis<PostDominatorTree>();
- if (DT[&Func->getEntryBlock()] == 0) {
- WorkList.clear();
- return MadeChanges;
- }
-
- // Scan the function marking blocks without post-dominance information as
- // live. Blocks without post-dominance information occur when there is an
- // infinite loop in the program. Because the infinite loop could contain a
- // function which unwinds, exits or has side-effects, we don't want to delete
- // the infinite loop or those blocks leading up to it.
- for (Function::iterator I = Func->begin(), E = Func->end(); I != E; ++I)
- if (DT[I] == 0 && ReachableBBs.count(I))
- for (pred_iterator PI = pred_begin(I), E = pred_end(I); PI != E; ++PI)
- markInstructionLive((*PI)->getTerminator());
-
- DOUT << "Processing work list\n";
-
- // AliveBlocks - Set of basic blocks that we know have instructions that are
- // alive in them...
- //
- std::set<BasicBlock*> AliveBlocks;
-
- // Process the work list of instructions that just became live... if they
- // became live, then that means that all of their operands are necessary as
- // well... make them live as well.
- //
- while (!WorkList.empty()) {
- Instruction *I = WorkList.back(); // Get an instruction that became live...
- WorkList.pop_back();
-
- BasicBlock *BB = I->getParent();
- if (!ReachableBBs.count(BB)) continue;
- if (AliveBlocks.insert(BB).second) // Basic block not alive yet.
- markBlockAlive(BB); // Make it so now!
-
- // PHI nodes are a special case, because the incoming values are actually
- // defined in the predecessor nodes of this block, meaning that the PHI
- // makes the predecessors alive.
- //
- if (PHINode *PN = dyn_cast<PHINode>(I)) {
- for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
- // If the incoming edge is clearly dead, it won't have control
- // dependence information. Do not mark it live.
- BasicBlock *PredBB = PN->getIncomingBlock(i);
- if (ReachableBBs.count(PredBB)) {
- // FIXME: This should mark the control dependent edge as live, not
- // necessarily the predecessor itself!
- if (AliveBlocks.insert(PredBB).second)
- markBlockAlive(PN->getIncomingBlock(i)); // Block is newly ALIVE!
- if (Instruction *Op = dyn_cast<Instruction>(PN->getIncomingValue(i)))
- markInstructionLive(Op);
- }
- }
- } else {
- // Loop over all of the operands of the live instruction, making sure that
- // they are known to be alive as well.
- //
- for (unsigned op = 0, End = I->getNumOperands(); op != End; ++op)
- if (Instruction *Operand = dyn_cast<Instruction>(I->getOperand(op)))
- markInstructionLive(Operand);
- }
+ // Propagate liveness backwards to operands.
+ while (!worklist.empty()) {
+ Instruction* curr = worklist.back();
+ worklist.pop_back();
+
+ for (Instruction::op_iterator OI = curr->op_begin(), OE = curr->op_end();
+ OI != OE; ++OI)
+ if (Instruction* Inst = dyn_cast<Instruction>(OI))
+ if (alive.insert(Inst))
+ worklist.push_back(Inst);
}
-
- DEBUG(
- DOUT << "Current Function: X = Live\n";
- for (Function::iterator I = Func->begin(), E = Func->end(); I != E; ++I){
- DOUT << I->getName() << ":\t"
- << (AliveBlocks.count(I) ? "LIVE\n" : "DEAD\n");
- for (BasicBlock::iterator BI = I->begin(), BE = I->end(); BI != BE; ++BI){
- if (LiveSet.count(BI)) DOUT << "X ";
- DOUT << *BI;
- }
- });
-
- // All blocks being live is a common case, handle it specially.
- if (AliveBlocks.size() == Func->size()) { // No dead blocks?
- for (Function::iterator I = Func->begin(), E = Func->end(); I != E; ++I) {
- // Loop over all of the instructions in the function deleting instructions
- // to drop their references.
- deleteDeadInstructionsInLiveBlock(I);
-
- // Check to make sure the terminator instruction is live. If it isn't,
- // this means that the condition that it branches on (we know it is not an
- // unconditional branch), is not needed to make the decision of where to
- // go to, because all outgoing edges go to the same place. We must remove
- // the use of the condition (because it's probably dead), so we convert
- // the terminator to an unconditional branch.
- //
- TerminatorInst *TI = I->getTerminator();
- if (!LiveSet.count(TI))
- convertToUnconditionalBranch(TI);
+
+ // The inverse of the live set is the dead set. These are those instructions
+ // which have no side effects and do not influence the control flow or return
+ // value of the function, and may therefore be deleted safely.
+ SmallPtrSet<Instruction*, 32> dead;
+ for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
+ if (!alive.count(I.getInstructionIterator())) {
+ dead.insert(I.getInstructionIterator());
+ I->dropAllReferences();
}
-
- return MadeChanges;
- }
-
-
- // If the entry node is dead, insert a new entry node to eliminate the entry
- // node as a special case.
- //
- if (!AliveBlocks.count(&Func->front())) {
- BasicBlock *NewEntry = BasicBlock::Create();
- BranchInst::Create(&Func->front(), NewEntry);
- Func->getBasicBlockList().push_front(NewEntry);
- AliveBlocks.insert(NewEntry); // This block is always alive!
- LiveSet.insert(NewEntry->getTerminator()); // The branch is live
+
+ for (SmallPtrSet<Instruction*, 32>::iterator I = dead.begin(),
+ E = dead.end(); I != E; ++I) {
+ NumRemoved++;
+ (*I)->eraseFromParent();
}
-
- // Loop over all of the alive blocks in the function. If any successor
- // blocks are not alive, we adjust the outgoing branches to branch to the
- // first live postdominator of the live block, adjusting any PHI nodes in
- // the block to reflect this.
- //
- for (Function::iterator I = Func->begin(), E = Func->end(); I != E; ++I)
- if (AliveBlocks.count(I)) {
- BasicBlock *BB = I;
- TerminatorInst *TI = BB->getTerminator();
-
- // If the terminator instruction is alive, but the block it is contained
- // in IS alive, this means that this terminator is a conditional branch on
- // a condition that doesn't matter. Make it an unconditional branch to
- // ONE of the successors. This has the side effect of dropping a use of
- // the conditional value, which may also be dead.
- if (!LiveSet.count(TI))
- TI = convertToUnconditionalBranch(TI);
-
- // Loop over all of the successors, looking for ones that are not alive.
- // We cannot save the number of successors in the terminator instruction
- // here because we may remove them if we don't have a postdominator.
- //
- for (unsigned i = 0; i != TI->getNumSuccessors(); ++i)
- if (!AliveBlocks.count(TI->getSuccessor(i))) {
- // Scan up the postdominator tree, looking for the first
- // postdominator that is alive, and the last postdominator that is
- // dead...
- //
- DomTreeNode *LastNode = DT[TI->getSuccessor(i)];
- DomTreeNode *NextNode = 0;
-
- if (LastNode) {
- NextNode = LastNode->getIDom();
- while (!AliveBlocks.count(NextNode->getBlock())) {
- LastNode = NextNode;
- NextNode = NextNode->getIDom();
- if (NextNode == 0) {
- LastNode = 0;
- break;
- }
- }
- }
-
- // There is a special case here... if there IS no post-dominator for
- // the block we have nowhere to point our branch to. Instead, convert
- // it to a return. This can only happen if the code branched into an
- // infinite loop. Note that this may not be desirable, because we
- // _are_ altering the behavior of the code. This is a well known
- // drawback of ADCE, so in the future if we choose to revisit the
- // decision, this is where it should be.
- //
- if (LastNode == 0) { // No postdominator!
- if (!isa<InvokeInst>(TI)) {
- // Call RemoveSuccessor to transmogrify the terminator instruction
- // to not contain the outgoing branch, or to create a new
- // terminator if the form fundamentally changes (i.e.,
- // unconditional branch to return). Note that this will change a
- // branch into an infinite loop into a return instruction!
- //
- RemoveSuccessor(TI, i);
-
- // RemoveSuccessor may replace TI... make sure we have a fresh
- // pointer.
- //
- TI = BB->getTerminator();
-
- // Rescan this successor...
- --i;
- } else {
-
- }
- } else {
- // Get the basic blocks that we need...
- BasicBlock *LastDead = LastNode->getBlock();
- BasicBlock *NextAlive = NextNode->getBlock();
-
- // Make the conditional branch now go to the next alive block...
- TI->getSuccessor(i)->removePredecessor(BB);
- TI->setSuccessor(i, NextAlive);
-
- // If there are PHI nodes in NextAlive, we need to add entries to
- // the PHI nodes for the new incoming edge. The incoming values
- // should be identical to the incoming values for LastDead.
- //
- for (BasicBlock::iterator II = NextAlive->begin();
- isa<PHINode>(II); ++II) {
- PHINode *PN = cast<PHINode>(II);
- if (LiveSet.count(PN)) { // Only modify live phi nodes
- // Get the incoming value for LastDead...
- int OldIdx = PN->getBasicBlockIndex(LastDead);
- assert(OldIdx != -1 &&"LastDead is not a pred of NextAlive!");
- Value *InVal = PN->getIncomingValue(OldIdx);
-
- // Add an incoming value for BB now...
- PN->addIncoming(InVal, BB);
- }
- }
- }
- }
-
- // Now loop over all of the instructions in the basic block, deleting
- // dead instructions. This is so that the next sweep over the program
- // can safely delete dead instructions without other dead instructions
- // still referring to them.
- //
- deleteDeadInstructionsInLiveBlock(BB);
- }
-
- // Loop over all of the basic blocks in the function, dropping references of
- // the dead basic blocks. We must do this after the previous step to avoid
- // dropping references to PHIs which still have entries...
- //
- std::vector<BasicBlock*> DeadBlocks;
- for (Function::iterator BB = Func->begin(), E = Func->end(); BB != E; ++BB)
- if (!AliveBlocks.count(BB)) {
- // Remove PHI node entries for this block in live successor blocks.
- for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
- if (!SI->empty() && isa<PHINode>(SI->front()) && AliveBlocks.count(*SI))
- (*SI)->removePredecessor(BB);
-
- BB->dropAllReferences();
- MadeChanges = true;
- DeadBlocks.push_back(BB);
- }
-
- NumBlockRemoved += DeadBlocks.size();
-
- // Now loop through all of the blocks and delete the dead ones. We can safely
- // do this now because we know that there are no references to dead blocks
- // (because they have dropped all of their references).
- for (std::vector<BasicBlock*>::iterator I = DeadBlocks.begin(),
- E = DeadBlocks.end(); I != E; ++I)
- Func->getBasicBlockList().erase(*I);
-
- return MadeChanges;
+
+ return !dead.empty();
}
+
+FunctionPass *llvm::createAggressiveDCEPass() {
+ return new ADCE();
+}
\ No newline at end of file
Removed: llvm/trunk/test/Transforms/ADCE/2003-12-19-MergeReturn.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ADCE/2003-12-19-MergeReturn.ll?rev=51667&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ADCE/2003-12-19-MergeReturn.ll (original)
+++ llvm/trunk/test/Transforms/ADCE/2003-12-19-MergeReturn.ll (removed)
@@ -1,27 +0,0 @@
-; This testcase was failing because without merging the return blocks, ADCE
-; didn't know that it could get rid of the then.0 block.
-
-; RUN: llvm-as < %s | opt -adce | llvm-dis | not grep load
-
-
-define void @main(i32 %argc, i8** %argv) {
-entry:
- call void @__main( )
- %tmp.1 = icmp ule i32 %argc, 5 ; <i1> [#uses=1]
- br i1 %tmp.1, label %then.0, label %return
-
-then.0: ; preds = %entry
- %tmp.8 = load i8** %argv ; <i8*> [#uses=1]
- %tmp.10 = load i8* %tmp.8 ; <i8> [#uses=1]
- %tmp.11 = icmp eq i8 %tmp.10, 98 ; <i1> [#uses=1]
- br i1 %tmp.11, label %then.1, label %return
-
-then.1: ; preds = %then.0
- ret void
-
-return: ; preds = %then.0, %entry
- ret void
-}
-
-declare void @__main()
-
Removed: llvm/trunk/test/Transforms/ADCE/dead-phi-edge.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ADCE/dead-phi-edge.ll?rev=51667&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/ADCE/dead-phi-edge.ll (original)
+++ llvm/trunk/test/Transforms/ADCE/dead-phi-edge.ll (removed)
@@ -1,17 +0,0 @@
-; RUN: llvm-as < %s | opt -adce | llvm-dis | not grep call
-
-; The call is not live just because the PHI uses the call retval!
-
-define i32 @test(i32 %X) {
-; <label>:0
- br label %Done
-
-DeadBlock: ; No predecessors!
- %Y = call i32 @test( i32 0 ) ; <i32> [#uses=1]
- br label %Done
-
-Done: ; preds = %DeadBlock, %0
- %Z = phi i32 [ %X, %0 ], [ %Y, %DeadBlock ] ; <i32> [#uses=1]
- ret i32 %Z
-}
-
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