2002-05-08 02:07:59 +08:00
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//===-- Local.cpp - Functions to perform local transformations ------------===//
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2005-04-22 07:48:37 +08:00
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//
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2003-10-21 03:43:21 +08:00
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// The LLVM Compiler Infrastructure
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//
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2007-12-30 04:36:04 +08:00
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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2005-04-22 07:48:37 +08:00
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//
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2003-10-21 03:43:21 +08:00
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//===----------------------------------------------------------------------===//
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2002-05-08 02:07:59 +08:00
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//
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// This family of functions perform various local transformations to the
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// program.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Transforms/Utils/Local.h"
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2004-01-13 02:35:03 +08:00
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#include "llvm/Constants.h"
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2009-06-17 01:23:12 +08:00
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#include "llvm/GlobalAlias.h"
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2009-03-06 08:19:37 +08:00
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#include "llvm/GlobalVariable.h"
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2005-09-26 13:27:10 +08:00
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#include "llvm/DerivedTypes.h"
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2004-01-13 03:56:36 +08:00
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#include "llvm/Instructions.h"
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2004-06-11 14:16:23 +08:00
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#include "llvm/Intrinsics.h"
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2007-12-29 08:59:12 +08:00
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#include "llvm/IntrinsicInst.h"
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2011-05-24 11:10:43 +08:00
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#include "llvm/Metadata.h"
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2011-04-11 17:35:34 +08:00
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#include "llvm/Operator.h"
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2009-12-29 17:12:29 +08:00
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#include "llvm/ADT/DenseMap.h"
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2009-05-03 02:29:22 +08:00
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#include "llvm/ADT/SmallPtrSet.h"
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2011-03-18 05:58:19 +08:00
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#include "llvm/Analysis/DebugInfo.h"
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#include "llvm/Analysis/DIBuilder.h"
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2011-01-09 01:01:52 +08:00
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#include "llvm/Analysis/Dominators.h"
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2009-11-11 06:26:15 +08:00
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#include "llvm/Analysis/InstructionSimplify.h"
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2011-10-24 12:35:36 +08:00
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#include "llvm/Analysis/MemoryBuiltins.h"
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2009-09-16 17:26:52 +08:00
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#include "llvm/Analysis/ProfileInfo.h"
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2010-12-26 04:37:57 +08:00
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#include "llvm/Analysis/ValueTracking.h"
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2007-01-31 07:13:49 +08:00
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#include "llvm/Target/TargetData.h"
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2009-11-10 13:59:26 +08:00
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#include "llvm/Support/CFG.h"
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#include "llvm/Support/Debug.h"
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2005-09-26 13:27:10 +08:00
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#include "llvm/Support/GetElementPtrTypeIterator.h"
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2011-05-19 01:37:10 +08:00
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#include "llvm/Support/IRBuilder.h"
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2005-09-26 13:27:10 +08:00
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#include "llvm/Support/MathExtras.h"
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2009-12-29 17:12:29 +08:00
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#include "llvm/Support/ValueHandle.h"
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2009-11-10 13:59:26 +08:00
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#include "llvm/Support/raw_ostream.h"
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2003-12-19 13:56:28 +08:00
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using namespace llvm;
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2003-11-12 06:41:34 +08:00
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2002-05-08 02:07:59 +08:00
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//===----------------------------------------------------------------------===//
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2008-11-28 06:57:53 +08:00
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// Local constant propagation.
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2002-05-08 02:07:59 +08:00
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//
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2011-05-23 00:24:18 +08:00
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/// ConstantFoldTerminator - If a terminator instruction is predicated on a
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/// constant value, convert it into an unconditional branch to the constant
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/// destination. This is a nontrivial operation because the successors of this
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/// basic block must have their PHI nodes updated.
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/// Also calls RecursivelyDeleteTriviallyDeadInstructions() on any branch/switch
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/// conditions and indirectbr addresses this might make dead if
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/// DeleteDeadConditions is true.
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bool llvm::ConstantFoldTerminator(BasicBlock *BB, bool DeleteDeadConditions) {
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2002-05-22 04:04:50 +08:00
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TerminatorInst *T = BB->getTerminator();
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2011-05-19 01:26:46 +08:00
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IRBuilder<> Builder(T);
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2005-04-22 07:48:37 +08:00
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2002-05-08 02:07:59 +08:00
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// Branch - See if we are conditional jumping on constant
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if (BranchInst *BI = dyn_cast<BranchInst>(T)) {
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if (BI->isUnconditional()) return false; // Can't optimize uncond branch
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2009-01-31 02:21:13 +08:00
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BasicBlock *Dest1 = BI->getSuccessor(0);
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BasicBlock *Dest2 = BI->getSuccessor(1);
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2002-05-08 02:07:59 +08:00
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2007-01-11 20:24:14 +08:00
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if (ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition())) {
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2002-05-08 02:07:59 +08:00
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// Are we branching on constant?
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// YES. Change to unconditional branch...
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2007-01-12 12:24:46 +08:00
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BasicBlock *Destination = Cond->getZExtValue() ? Dest1 : Dest2;
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BasicBlock *OldDest = Cond->getZExtValue() ? Dest2 : Dest1;
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2002-05-08 02:07:59 +08:00
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2005-04-22 07:48:37 +08:00
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//cerr << "Function: " << T->getParent()->getParent()
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// << "\nRemoving branch from " << T->getParent()
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2002-05-08 02:07:59 +08:00
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// << "\n\nTo: " << OldDest << endl;
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// Let the basic block know that we are letting go of it. Based on this,
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// it will adjust it's PHI nodes.
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2011-04-19 23:23:29 +08:00
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OldDest->removePredecessor(BB);
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2002-05-08 02:07:59 +08:00
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2011-01-08 04:25:56 +08:00
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// Replace the conditional branch with an unconditional one.
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2011-05-19 01:26:46 +08:00
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Builder.CreateBr(Destination);
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2011-01-08 04:25:56 +08:00
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BI->eraseFromParent();
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2002-05-08 02:07:59 +08:00
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return true;
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2009-11-01 11:40:38 +08:00
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}
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if (Dest2 == Dest1) { // Conditional branch to same location?
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2005-04-22 07:48:37 +08:00
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// This branch matches something like this:
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2002-05-08 02:07:59 +08:00
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// br bool %cond, label %Dest, label %Dest
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// and changes it into: br label %Dest
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// Let the basic block know that we are letting go of one copy of it.
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assert(BI->getParent() && "Terminator not inserted in block!");
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Dest1->removePredecessor(BI->getParent());
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2011-01-08 04:25:56 +08:00
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// Replace the conditional branch with an unconditional one.
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2011-05-19 01:26:46 +08:00
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Builder.CreateBr(Dest1);
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2011-05-23 00:24:18 +08:00
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Value *Cond = BI->getCondition();
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2011-01-08 04:25:56 +08:00
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BI->eraseFromParent();
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2011-05-23 00:24:18 +08:00
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if (DeleteDeadConditions)
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RecursivelyDeleteTriviallyDeadInstructions(Cond);
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2002-05-08 02:07:59 +08:00
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return true;
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}
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2009-11-01 11:40:38 +08:00
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return false;
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}
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if (SwitchInst *SI = dyn_cast<SwitchInst>(T)) {
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2003-08-18 04:21:14 +08:00
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// If we are switching on a constant, we can convert the switch into a
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// single branch instruction!
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ConstantInt *CI = dyn_cast<ConstantInt>(SI->getCondition());
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BasicBlock *TheOnlyDest = SI->getSuccessor(0); // The default dest
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2003-08-24 07:18:19 +08:00
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BasicBlock *DefaultDest = TheOnlyDest;
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assert(TheOnlyDest == SI->getDefaultDest() &&
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"Default destination is not successor #0?");
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2003-08-18 04:21:14 +08:00
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2009-11-01 11:40:38 +08:00
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// Figure out which case it goes to.
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2003-08-18 04:21:14 +08:00
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for (unsigned i = 1, e = SI->getNumSuccessors(); i != e; ++i) {
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// Found case matching a constant operand?
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if (SI->getSuccessorValue(i) == CI) {
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TheOnlyDest = SI->getSuccessor(i);
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break;
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}
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2003-08-24 07:18:19 +08:00
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// Check to see if this branch is going to the same place as the default
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// dest. If so, eliminate it as an explicit compare.
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if (SI->getSuccessor(i) == DefaultDest) {
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2009-11-01 11:40:38 +08:00
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// Remove this entry.
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2003-08-24 07:18:19 +08:00
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DefaultDest->removePredecessor(SI->getParent());
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SI->removeCase(i);
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--i; --e; // Don't skip an entry...
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continue;
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}
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2003-08-18 04:21:14 +08:00
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// Otherwise, check to see if the switch only branches to one destination.
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// We do this by reseting "TheOnlyDest" to null when we find two non-equal
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// destinations.
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if (SI->getSuccessor(i) != TheOnlyDest) TheOnlyDest = 0;
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}
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2003-08-18 03:41:53 +08:00
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2003-08-18 04:21:14 +08:00
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if (CI && !TheOnlyDest) {
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// Branching on a constant, but not any of the cases, go to the default
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// successor.
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TheOnlyDest = SI->getDefaultDest();
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2003-08-18 03:41:53 +08:00
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}
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2003-08-18 04:21:14 +08:00
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// If we found a single destination that we can fold the switch into, do so
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// now.
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if (TheOnlyDest) {
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2009-11-01 11:40:38 +08:00
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// Insert the new branch.
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2011-05-19 01:26:46 +08:00
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Builder.CreateBr(TheOnlyDest);
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2003-08-18 04:21:14 +08:00
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BasicBlock *BB = SI->getParent();
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// Remove entries from PHI nodes which we no longer branch to...
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for (unsigned i = 0, e = SI->getNumSuccessors(); i != e; ++i) {
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// Found case matching a constant operand?
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BasicBlock *Succ = SI->getSuccessor(i);
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if (Succ == TheOnlyDest)
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TheOnlyDest = 0; // Don't modify the first branch to TheOnlyDest
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else
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Succ->removePredecessor(BB);
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}
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2009-11-01 11:40:38 +08:00
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// Delete the old switch.
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2011-05-23 00:24:18 +08:00
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Value *Cond = SI->getCondition();
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SI->eraseFromParent();
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if (DeleteDeadConditions)
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RecursivelyDeleteTriviallyDeadInstructions(Cond);
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2003-08-18 04:21:14 +08:00
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return true;
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2009-11-01 11:40:38 +08:00
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}
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if (SI->getNumSuccessors() == 2) {
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2003-08-18 04:21:14 +08:00
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// Otherwise, we can fold this switch into a conditional branch
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// instruction if it has only one non-default destination.
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2011-05-19 01:26:46 +08:00
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Value *Cond = Builder.CreateICmpEQ(SI->getCondition(),
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SI->getSuccessorValue(1), "cond");
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2009-11-01 11:40:38 +08:00
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// Insert the new branch.
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2011-05-19 01:26:46 +08:00
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Builder.CreateCondBr(Cond, SI->getSuccessor(1), SI->getSuccessor(0));
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2003-08-18 04:21:14 +08:00
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2009-11-01 11:40:38 +08:00
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// Delete the old switch.
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2008-06-22 06:08:46 +08:00
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SI->eraseFromParent();
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2003-08-18 04:21:14 +08:00
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return true;
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}
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2009-11-01 11:40:38 +08:00
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return false;
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}
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if (IndirectBrInst *IBI = dyn_cast<IndirectBrInst>(T)) {
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// indirectbr blockaddress(@F, @BB) -> br label @BB
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if (BlockAddress *BA =
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dyn_cast<BlockAddress>(IBI->getAddress()->stripPointerCasts())) {
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BasicBlock *TheOnlyDest = BA->getBasicBlock();
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// Insert the new branch.
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2011-05-19 01:26:46 +08:00
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Builder.CreateBr(TheOnlyDest);
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2009-11-01 11:40:38 +08:00
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for (unsigned i = 0, e = IBI->getNumDestinations(); i != e; ++i) {
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if (IBI->getDestination(i) == TheOnlyDest)
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TheOnlyDest = 0;
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else
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IBI->getDestination(i)->removePredecessor(IBI->getParent());
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}
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2011-05-23 00:24:18 +08:00
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Value *Address = IBI->getAddress();
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2009-11-01 11:40:38 +08:00
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IBI->eraseFromParent();
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2011-05-23 00:24:18 +08:00
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if (DeleteDeadConditions)
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RecursivelyDeleteTriviallyDeadInstructions(Address);
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2009-11-01 11:40:38 +08:00
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// If we didn't find our destination in the IBI successor list, then we
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// have undefined behavior. Replace the unconditional branch with an
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// 'unreachable' instruction.
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if (TheOnlyDest) {
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BB->getTerminator()->eraseFromParent();
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new UnreachableInst(BB->getContext(), BB);
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}
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return true;
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}
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2002-05-08 02:07:59 +08:00
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}
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2009-11-01 11:40:38 +08:00
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2002-05-08 02:07:59 +08:00
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return false;
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}
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//===----------------------------------------------------------------------===//
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2009-11-11 06:26:15 +08:00
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// Local dead code elimination.
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2002-05-08 02:07:59 +08:00
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//
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2008-11-28 06:57:53 +08:00
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/// isInstructionTriviallyDead - Return true if the result produced by the
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/// instruction is not used, and the instruction has no side effects.
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///
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2003-12-19 13:56:28 +08:00
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bool llvm::isInstructionTriviallyDead(Instruction *I) {
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2005-05-06 13:27:34 +08:00
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if (!I->use_empty() || isa<TerminatorInst>(I)) return false;
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2005-07-27 14:12:32 +08:00
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2011-08-16 04:10:51 +08:00
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// We don't want the landingpad instruction removed by anything this general.
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if (isa<LandingPadInst>(I))
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return false;
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2011-03-19 07:28:02 +08:00
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// We don't want debug info removed by anything this general, unless
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// debug info is empty.
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if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
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2011-08-03 05:19:27 +08:00
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if (DDI->getAddress())
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2011-03-19 07:28:02 +08:00
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return false;
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2011-03-22 06:04:45 +08:00
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return true;
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2011-08-03 05:19:27 +08:00
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}
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2011-03-22 06:04:45 +08:00
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if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
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2011-03-19 07:28:02 +08:00
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if (DVI->getValue())
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return false;
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2011-03-22 06:04:45 +08:00
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return true;
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2011-03-19 07:28:02 +08:00
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}
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2009-05-06 14:49:50 +08:00
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if (!I->mayHaveSideEffects()) return true;
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// Special case intrinsics that "may have side effects" but can be deleted
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// when dead.
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2011-08-03 05:19:27 +08:00
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if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
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2007-12-29 08:59:12 +08:00
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// Safe to delete llvm.stacksave if dead.
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if (II->getIntrinsicID() == Intrinsic::stacksave)
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return true;
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2011-08-03 05:19:27 +08:00
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// Lifetime intrinsics are dead when their right-hand is undef.
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if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
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II->getIntrinsicID() == Intrinsic::lifetime_end)
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return isa<UndefValue>(II->getArgOperand(1));
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}
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2011-10-24 12:35:36 +08:00
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if (extractMallocCall(I)) return true;
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if (CallInst *CI = isFreeCall(I))
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if (Constant *C = dyn_cast<Constant>(CI->getArgOperand(0)))
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return C->isNullValue() || isa<UndefValue>(C);
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2005-05-06 13:27:34 +08:00
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return false;
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2002-05-08 02:07:59 +08:00
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}
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2008-11-28 06:57:53 +08:00
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/// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a
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/// trivially dead instruction, delete it. If that makes any of its operands
|
2010-01-05 23:45:31 +08:00
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/// trivially dead, delete them too, recursively. Return true if any
|
|
|
|
/// instructions were deleted.
|
|
|
|
bool llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
|
2008-11-28 06:57:53 +08:00
|
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
2008-11-28 09:20:46 +08:00
|
|
|
if (!I || !I->use_empty() || !isInstructionTriviallyDead(I))
|
2010-01-05 23:45:31 +08:00
|
|
|
return false;
|
2008-11-28 06:57:53 +08:00
|
|
|
|
2008-11-28 09:20:46 +08:00
|
|
|
SmallVector<Instruction*, 16> DeadInsts;
|
|
|
|
DeadInsts.push_back(I);
|
2008-11-28 06:57:53 +08:00
|
|
|
|
2010-01-06 00:27:25 +08:00
|
|
|
do {
|
2009-05-07 01:22:41 +08:00
|
|
|
I = DeadInsts.pop_back_val();
|
2008-11-28 08:58:15 +08:00
|
|
|
|
2008-11-28 09:20:46 +08:00
|
|
|
// Null out all of the instruction's operands to see if any operand becomes
|
|
|
|
// dead as we go.
|
|
|
|
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i) {
|
|
|
|
Value *OpV = I->getOperand(i);
|
|
|
|
I->setOperand(i, 0);
|
|
|
|
|
|
|
|
if (!OpV->use_empty()) continue;
|
|
|
|
|
|
|
|
// If the operand is an instruction that became dead as we nulled out the
|
|
|
|
// operand, and if it is 'trivially' dead, delete it in a future loop
|
|
|
|
// iteration.
|
|
|
|
if (Instruction *OpI = dyn_cast<Instruction>(OpV))
|
|
|
|
if (isInstructionTriviallyDead(OpI))
|
|
|
|
DeadInsts.push_back(OpI);
|
|
|
|
}
|
|
|
|
|
|
|
|
I->eraseFromParent();
|
2010-01-06 00:27:25 +08:00
|
|
|
} while (!DeadInsts.empty());
|
2010-01-05 23:45:31 +08:00
|
|
|
|
|
|
|
return true;
|
2002-05-08 02:07:59 +08:00
|
|
|
}
|
2008-11-27 15:43:12 +08:00
|
|
|
|
2011-02-20 16:38:20 +08:00
|
|
|
/// areAllUsesEqual - Check whether the uses of a value are all the same.
|
|
|
|
/// This is similar to Instruction::hasOneUse() except this will also return
|
2011-02-22 00:27:36 +08:00
|
|
|
/// true when there are no uses or multiple uses that all refer to the same
|
|
|
|
/// value.
|
2011-02-20 16:38:20 +08:00
|
|
|
static bool areAllUsesEqual(Instruction *I) {
|
|
|
|
Value::use_iterator UI = I->use_begin();
|
|
|
|
Value::use_iterator UE = I->use_end();
|
|
|
|
if (UI == UE)
|
2011-02-22 00:27:36 +08:00
|
|
|
return true;
|
2011-02-20 16:38:20 +08:00
|
|
|
|
|
|
|
User *TheUse = *UI;
|
|
|
|
for (++UI; UI != UE; ++UI) {
|
|
|
|
if (*UI != TheUse)
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
2009-05-03 02:29:22 +08:00
|
|
|
/// RecursivelyDeleteDeadPHINode - If the specified value is an effectively
|
|
|
|
/// dead PHI node, due to being a def-use chain of single-use nodes that
|
|
|
|
/// either forms a cycle or is terminated by a trivially dead instruction,
|
|
|
|
/// delete it. If that makes any of its operands trivially dead, delete them
|
2011-02-22 01:32:05 +08:00
|
|
|
/// too, recursively. Return true if a change was made.
|
2011-02-20 16:38:20 +08:00
|
|
|
bool llvm::RecursivelyDeleteDeadPHINode(PHINode *PN) {
|
2011-02-22 00:27:36 +08:00
|
|
|
SmallPtrSet<Instruction*, 4> Visited;
|
|
|
|
for (Instruction *I = PN; areAllUsesEqual(I) && !I->mayHaveSideEffects();
|
|
|
|
I = cast<Instruction>(*I->use_begin())) {
|
|
|
|
if (I->use_empty())
|
|
|
|
return RecursivelyDeleteTriviallyDeadInstructions(I);
|
2009-05-03 02:29:22 +08:00
|
|
|
|
2011-02-22 00:27:36 +08:00
|
|
|
// If we find an instruction more than once, we're on a cycle that
|
2009-05-03 02:29:22 +08:00
|
|
|
// won't prove fruitful.
|
2011-02-22 00:27:36 +08:00
|
|
|
if (!Visited.insert(I)) {
|
|
|
|
// Break the cycle and delete the instruction and its operands.
|
|
|
|
I->replaceAllUsesWith(UndefValue::get(I->getType()));
|
2011-02-22 01:32:05 +08:00
|
|
|
(void)RecursivelyDeleteTriviallyDeadInstructions(I);
|
|
|
|
return true;
|
2011-02-22 00:27:36 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
return false;
|
2009-05-03 02:29:22 +08:00
|
|
|
}
|
2008-11-28 06:57:53 +08:00
|
|
|
|
2010-01-13 03:40:54 +08:00
|
|
|
/// SimplifyInstructionsInBlock - Scan the specified basic block and try to
|
|
|
|
/// simplify any instructions in it and recursively delete dead instructions.
|
|
|
|
///
|
|
|
|
/// This returns true if it changed the code, note that it can delete
|
|
|
|
/// instructions in other blocks as well in this block.
|
|
|
|
bool llvm::SimplifyInstructionsInBlock(BasicBlock *BB, const TargetData *TD) {
|
|
|
|
bool MadeChange = false;
|
|
|
|
for (BasicBlock::iterator BI = BB->begin(), E = BB->end(); BI != E; ) {
|
|
|
|
Instruction *Inst = BI++;
|
|
|
|
|
|
|
|
if (Value *V = SimplifyInstruction(Inst, TD)) {
|
|
|
|
WeakVH BIHandle(BI);
|
|
|
|
ReplaceAndSimplifyAllUses(Inst, V, TD);
|
|
|
|
MadeChange = true;
|
2010-07-15 14:06:04 +08:00
|
|
|
if (BIHandle != BI)
|
2010-01-13 03:40:54 +08:00
|
|
|
BI = BB->begin();
|
|
|
|
continue;
|
|
|
|
}
|
2011-04-03 06:45:17 +08:00
|
|
|
|
2011-04-04 08:37:38 +08:00
|
|
|
if (Inst->isTerminator())
|
|
|
|
break;
|
|
|
|
|
2011-04-03 06:45:17 +08:00
|
|
|
WeakVH BIHandle(BI);
|
2010-01-13 03:40:54 +08:00
|
|
|
MadeChange |= RecursivelyDeleteTriviallyDeadInstructions(Inst);
|
2011-04-03 06:45:17 +08:00
|
|
|
if (BIHandle != BI)
|
|
|
|
BI = BB->begin();
|
2010-01-13 03:40:54 +08:00
|
|
|
}
|
|
|
|
return MadeChange;
|
|
|
|
}
|
|
|
|
|
2008-11-27 15:43:12 +08:00
|
|
|
//===----------------------------------------------------------------------===//
|
2009-11-11 06:26:15 +08:00
|
|
|
// Control Flow Graph Restructuring.
|
2008-11-27 15:43:12 +08:00
|
|
|
//
|
|
|
|
|
2009-11-11 06:26:15 +08:00
|
|
|
|
|
|
|
/// RemovePredecessorAndSimplify - Like BasicBlock::removePredecessor, this
|
|
|
|
/// method is called when we're about to delete Pred as a predecessor of BB. If
|
|
|
|
/// BB contains any PHI nodes, this drops the entries in the PHI nodes for Pred.
|
|
|
|
///
|
|
|
|
/// Unlike the removePredecessor method, this attempts to simplify uses of PHI
|
|
|
|
/// nodes that collapse into identity values. For example, if we have:
|
|
|
|
/// x = phi(1, 0, 0, 0)
|
|
|
|
/// y = and x, z
|
|
|
|
///
|
|
|
|
/// .. and delete the predecessor corresponding to the '1', this will attempt to
|
|
|
|
/// recursively fold the and to 0.
|
|
|
|
void llvm::RemovePredecessorAndSimplify(BasicBlock *BB, BasicBlock *Pred,
|
|
|
|
TargetData *TD) {
|
|
|
|
// This only adjusts blocks with PHI nodes.
|
|
|
|
if (!isa<PHINode>(BB->begin()))
|
|
|
|
return;
|
|
|
|
|
|
|
|
// Remove the entries for Pred from the PHI nodes in BB, but do not simplify
|
|
|
|
// them down. This will leave us with single entry phi nodes and other phis
|
|
|
|
// that can be removed.
|
|
|
|
BB->removePredecessor(Pred, true);
|
|
|
|
|
|
|
|
WeakVH PhiIt = &BB->front();
|
|
|
|
while (PHINode *PN = dyn_cast<PHINode>(PhiIt)) {
|
|
|
|
PhiIt = &*++BasicBlock::iterator(cast<Instruction>(PhiIt));
|
2010-11-17 12:12:05 +08:00
|
|
|
|
|
|
|
Value *PNV = SimplifyInstruction(PN, TD);
|
2009-11-11 06:26:15 +08:00
|
|
|
if (PNV == 0) continue;
|
2010-11-17 12:12:05 +08:00
|
|
|
|
2009-11-11 06:26:15 +08:00
|
|
|
// If we're able to simplify the phi to a single value, substitute the new
|
|
|
|
// value into all of its uses.
|
2010-11-17 12:12:05 +08:00
|
|
|
assert(PNV != PN && "SimplifyInstruction broken!");
|
2009-11-11 06:26:15 +08:00
|
|
|
|
2010-07-15 14:06:04 +08:00
|
|
|
Value *OldPhiIt = PhiIt;
|
2009-11-11 06:26:15 +08:00
|
|
|
ReplaceAndSimplifyAllUses(PN, PNV, TD);
|
|
|
|
|
|
|
|
// If recursive simplification ended up deleting the next PHI node we would
|
|
|
|
// iterate to, then our iterator is invalid, restart scanning from the top
|
|
|
|
// of the block.
|
2010-07-15 14:06:04 +08:00
|
|
|
if (PhiIt != OldPhiIt) PhiIt = &BB->front();
|
2009-11-11 06:26:15 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
|
2008-11-27 15:43:12 +08:00
|
|
|
/// MergeBasicBlockIntoOnlyPred - DestBB is a block with one predecessor and its
|
|
|
|
/// predecessor is known to have one successor (DestBB!). Eliminate the edge
|
|
|
|
/// between them, moving the instructions in the predecessor into DestBB and
|
|
|
|
/// deleting the predecessor block.
|
|
|
|
///
|
2009-09-16 17:26:52 +08:00
|
|
|
void llvm::MergeBasicBlockIntoOnlyPred(BasicBlock *DestBB, Pass *P) {
|
2008-11-27 15:43:12 +08:00
|
|
|
// If BB has single-entry PHI nodes, fold them.
|
|
|
|
while (PHINode *PN = dyn_cast<PHINode>(DestBB->begin())) {
|
|
|
|
Value *NewVal = PN->getIncomingValue(0);
|
|
|
|
// Replace self referencing PHI with undef, it must be dead.
|
2009-07-31 07:03:37 +08:00
|
|
|
if (NewVal == PN) NewVal = UndefValue::get(PN->getType());
|
2008-11-27 15:43:12 +08:00
|
|
|
PN->replaceAllUsesWith(NewVal);
|
|
|
|
PN->eraseFromParent();
|
|
|
|
}
|
|
|
|
|
|
|
|
BasicBlock *PredBB = DestBB->getSinglePredecessor();
|
|
|
|
assert(PredBB && "Block doesn't have a single predecessor!");
|
|
|
|
|
2010-02-16 04:47:49 +08:00
|
|
|
// Zap anything that took the address of DestBB. Not doing this will give the
|
|
|
|
// address an invalid value.
|
|
|
|
if (DestBB->hasAddressTaken()) {
|
|
|
|
BlockAddress *BA = BlockAddress::get(DestBB);
|
|
|
|
Constant *Replacement =
|
|
|
|
ConstantInt::get(llvm::Type::getInt32Ty(BA->getContext()), 1);
|
|
|
|
BA->replaceAllUsesWith(ConstantExpr::getIntToPtr(Replacement,
|
|
|
|
BA->getType()));
|
|
|
|
BA->destroyConstant();
|
|
|
|
}
|
2008-11-27 15:43:12 +08:00
|
|
|
|
|
|
|
// Anything that branched to PredBB now branches to DestBB.
|
|
|
|
PredBB->replaceAllUsesWith(DestBB);
|
|
|
|
|
2011-06-23 17:09:15 +08:00
|
|
|
// Splice all the instructions from PredBB to DestBB.
|
|
|
|
PredBB->getTerminator()->eraseFromParent();
|
|
|
|
DestBB->getInstList().splice(DestBB->begin(), PredBB->getInstList());
|
|
|
|
|
2009-09-16 17:26:52 +08:00
|
|
|
if (P) {
|
2011-01-09 01:01:52 +08:00
|
|
|
DominatorTree *DT = P->getAnalysisIfAvailable<DominatorTree>();
|
|
|
|
if (DT) {
|
|
|
|
BasicBlock *PredBBIDom = DT->getNode(PredBB)->getIDom()->getBlock();
|
|
|
|
DT->changeImmediateDominator(DestBB, PredBBIDom);
|
|
|
|
DT->eraseNode(PredBB);
|
|
|
|
}
|
2009-09-16 17:26:52 +08:00
|
|
|
ProfileInfo *PI = P->getAnalysisIfAvailable<ProfileInfo>();
|
|
|
|
if (PI) {
|
|
|
|
PI->replaceAllUses(PredBB, DestBB);
|
|
|
|
PI->removeEdge(ProfileInfo::getEdge(PredBB, DestBB));
|
|
|
|
}
|
|
|
|
}
|
2008-11-27 15:43:12 +08:00
|
|
|
// Nuke BB.
|
|
|
|
PredBB->eraseFromParent();
|
|
|
|
}
|
2009-02-10 15:00:59 +08:00
|
|
|
|
2009-11-10 13:59:26 +08:00
|
|
|
/// CanPropagatePredecessorsForPHIs - Return true if we can fold BB, an
|
|
|
|
/// almost-empty BB ending in an unconditional branch to Succ, into succ.
|
|
|
|
///
|
|
|
|
/// Assumption: Succ is the single successor for BB.
|
|
|
|
///
|
|
|
|
static bool CanPropagatePredecessorsForPHIs(BasicBlock *BB, BasicBlock *Succ) {
|
|
|
|
assert(*succ_begin(BB) == Succ && "Succ is not successor of BB!");
|
|
|
|
|
2010-01-05 09:26:57 +08:00
|
|
|
DEBUG(dbgs() << "Looking to fold " << BB->getName() << " into "
|
2009-11-10 13:59:26 +08:00
|
|
|
<< Succ->getName() << "\n");
|
|
|
|
// Shortcut, if there is only a single predecessor it must be BB and merging
|
|
|
|
// is always safe
|
|
|
|
if (Succ->getSinglePredecessor()) return true;
|
|
|
|
|
|
|
|
// Make a list of the predecessors of BB
|
2011-12-07 00:14:29 +08:00
|
|
|
SmallPtrSet<BasicBlock*, 16> BBPreds(pred_begin(BB), pred_end(BB));
|
2009-11-10 13:59:26 +08:00
|
|
|
|
|
|
|
// Look at all the phi nodes in Succ, to see if they present a conflict when
|
|
|
|
// merging these blocks
|
|
|
|
for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
|
|
|
|
PHINode *PN = cast<PHINode>(I);
|
|
|
|
|
|
|
|
// If the incoming value from BB is again a PHINode in
|
|
|
|
// BB which has the same incoming value for *PI as PN does, we can
|
|
|
|
// merge the phi nodes and then the blocks can still be merged
|
|
|
|
PHINode *BBPN = dyn_cast<PHINode>(PN->getIncomingValueForBlock(BB));
|
|
|
|
if (BBPN && BBPN->getParent() == BB) {
|
2011-12-07 00:14:29 +08:00
|
|
|
for (unsigned PI = 0, PE = PN->getNumIncomingValues(); PI != PE; ++PI) {
|
|
|
|
BasicBlock *IBB = PN->getIncomingBlock(PI);
|
|
|
|
if (BBPreds.count(IBB) &&
|
|
|
|
BBPN->getIncomingValueForBlock(IBB) != PN->getIncomingValue(PI)) {
|
2010-01-05 09:26:57 +08:00
|
|
|
DEBUG(dbgs() << "Can't fold, phi node " << PN->getName() << " in "
|
2009-11-10 13:59:26 +08:00
|
|
|
<< Succ->getName() << " is conflicting with "
|
|
|
|
<< BBPN->getName() << " with regard to common predecessor "
|
2011-12-07 00:14:29 +08:00
|
|
|
<< IBB->getName() << "\n");
|
2009-11-10 13:59:26 +08:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
Value* Val = PN->getIncomingValueForBlock(BB);
|
2011-12-07 00:14:29 +08:00
|
|
|
for (unsigned PI = 0, PE = PN->getNumIncomingValues(); PI != PE; ++PI) {
|
2009-11-10 13:59:26 +08:00
|
|
|
// See if the incoming value for the common predecessor is equal to the
|
|
|
|
// one for BB, in which case this phi node will not prevent the merging
|
|
|
|
// of the block.
|
2011-12-07 00:14:29 +08:00
|
|
|
BasicBlock *IBB = PN->getIncomingBlock(PI);
|
|
|
|
if (BBPreds.count(IBB) && Val != PN->getIncomingValue(PI)) {
|
2010-01-05 09:26:57 +08:00
|
|
|
DEBUG(dbgs() << "Can't fold, phi node " << PN->getName() << " in "
|
2009-11-10 13:59:26 +08:00
|
|
|
<< Succ->getName() << " is conflicting with regard to common "
|
2011-12-07 00:14:29 +08:00
|
|
|
<< "predecessor " << IBB->getName() << "\n");
|
2009-11-10 13:59:26 +08:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
|
|
|
/// TryToSimplifyUncondBranchFromEmptyBlock - BB is known to contain an
|
|
|
|
/// unconditional branch, and contains no instructions other than PHI nodes,
|
2011-07-01 04:14:24 +08:00
|
|
|
/// 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.
|
2009-11-10 13:59:26 +08:00
|
|
|
bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB) {
|
2010-08-14 08:29:42 +08:00
|
|
|
assert(BB != &BB->getParent()->getEntryBlock() &&
|
|
|
|
"TryToSimplifyUncondBranchFromEmptyBlock called on entry block!");
|
|
|
|
|
2009-11-10 13:59:26 +08:00
|
|
|
// We can't eliminate infinite loops.
|
|
|
|
BasicBlock *Succ = cast<BranchInst>(BB->getTerminator())->getSuccessor(0);
|
|
|
|
if (BB == Succ) return false;
|
|
|
|
|
|
|
|
// Check to see if merging these blocks would cause conflicts for any of the
|
|
|
|
// phi nodes in BB or Succ. If not, we can safely merge.
|
|
|
|
if (!CanPropagatePredecessorsForPHIs(BB, Succ)) return false;
|
|
|
|
|
|
|
|
// Check for cases where Succ has multiple predecessors and a PHI node in BB
|
|
|
|
// has uses which will not disappear when the PHI nodes are merged. It is
|
|
|
|
// possible to handle such cases, but difficult: it requires checking whether
|
|
|
|
// BB dominates Succ, which is non-trivial to calculate in the case where
|
|
|
|
// Succ has multiple predecessors. Also, it requires checking whether
|
|
|
|
// constructing the necessary self-referential PHI node doesn't intoduce any
|
|
|
|
// conflicts; this isn't too difficult, but the previous code for doing this
|
|
|
|
// was incorrect.
|
|
|
|
//
|
|
|
|
// Note that if this check finds a live use, BB dominates Succ, so BB is
|
|
|
|
// something like a loop pre-header (or rarely, a part of an irreducible CFG);
|
|
|
|
// folding the branch isn't profitable in that case anyway.
|
|
|
|
if (!Succ->getSinglePredecessor()) {
|
|
|
|
BasicBlock::iterator BBI = BB->begin();
|
|
|
|
while (isa<PHINode>(*BBI)) {
|
|
|
|
for (Value::use_iterator UI = BBI->use_begin(), E = BBI->use_end();
|
|
|
|
UI != E; ++UI) {
|
|
|
|
if (PHINode* PN = dyn_cast<PHINode>(*UI)) {
|
|
|
|
if (PN->getIncomingBlock(UI) != BB)
|
|
|
|
return false;
|
|
|
|
} else {
|
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
++BBI;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-01-05 09:26:57 +08:00
|
|
|
DEBUG(dbgs() << "Killing Trivial BB: \n" << *BB);
|
2009-11-10 13:59:26 +08:00
|
|
|
|
|
|
|
if (isa<PHINode>(Succ->begin())) {
|
|
|
|
// If there is more than one pred of succ, and there are PHI nodes in
|
|
|
|
// the successor, then we need to add incoming edges for the PHI nodes
|
|
|
|
//
|
|
|
|
const SmallVector<BasicBlock*, 16> BBPreds(pred_begin(BB), pred_end(BB));
|
|
|
|
|
|
|
|
// Loop over all of the PHI nodes in the successor of BB.
|
|
|
|
for (BasicBlock::iterator I = Succ->begin(); isa<PHINode>(I); ++I) {
|
|
|
|
PHINode *PN = cast<PHINode>(I);
|
|
|
|
Value *OldVal = PN->removeIncomingValue(BB, false);
|
|
|
|
assert(OldVal && "No entry in PHI for Pred BB!");
|
|
|
|
|
|
|
|
// If this incoming value is one of the PHI nodes in BB, the new entries
|
|
|
|
// in the PHI node are the entries from the old PHI.
|
|
|
|
if (isa<PHINode>(OldVal) && cast<PHINode>(OldVal)->getParent() == BB) {
|
|
|
|
PHINode *OldValPN = cast<PHINode>(OldVal);
|
|
|
|
for (unsigned i = 0, e = OldValPN->getNumIncomingValues(); i != e; ++i)
|
|
|
|
// Note that, since we are merging phi nodes and BB and Succ might
|
|
|
|
// have common predecessors, we could end up with a phi node with
|
|
|
|
// identical incoming branches. This will be cleaned up later (and
|
|
|
|
// will trigger asserts if we try to clean it up now, without also
|
|
|
|
// simplifying the corresponding conditional branch).
|
|
|
|
PN->addIncoming(OldValPN->getIncomingValue(i),
|
|
|
|
OldValPN->getIncomingBlock(i));
|
|
|
|
} else {
|
|
|
|
// Add an incoming value for each of the new incoming values.
|
|
|
|
for (unsigned i = 0, e = BBPreds.size(); i != e; ++i)
|
|
|
|
PN->addIncoming(OldVal, BBPreds[i]);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-07-01 04:14:24 +08:00
|
|
|
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->getFirstNonPHI(), BB->getInstList());
|
|
|
|
} else {
|
|
|
|
while (PHINode *PN = dyn_cast<PHINode>(&BB->front())) {
|
2009-11-10 13:59:26 +08:00
|
|
|
// We explicitly check for such uses in CanPropagatePredecessorsForPHIs.
|
|
|
|
assert(PN->use_empty() && "There shouldn't be any uses here!");
|
|
|
|
PN->eraseFromParent();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Everything that jumped to BB now goes to Succ.
|
|
|
|
BB->replaceAllUsesWith(Succ);
|
|
|
|
if (!Succ->hasName()) Succ->takeName(BB);
|
|
|
|
BB->eraseFromParent(); // Delete the old basic block.
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
2009-12-03 01:06:45 +08:00
|
|
|
/// EliminateDuplicatePHINodes - Check for and eliminate duplicate PHI
|
|
|
|
/// nodes in this block. This doesn't try to be clever about PHI nodes
|
|
|
|
/// which differ only in the order of the incoming values, but instcombine
|
|
|
|
/// orders them so it usually won't matter.
|
|
|
|
///
|
|
|
|
bool llvm::EliminateDuplicatePHINodes(BasicBlock *BB) {
|
|
|
|
bool Changed = false;
|
|
|
|
|
|
|
|
// This implementation doesn't currently consider undef operands
|
2011-06-28 11:57:31 +08:00
|
|
|
// specially. Theoretically, two phis which are identical except for
|
2009-12-03 01:06:45 +08:00
|
|
|
// one having an undef where the other doesn't could be collapsed.
|
|
|
|
|
|
|
|
// Map from PHI hash values to PHI nodes. If multiple PHIs have
|
|
|
|
// the same hash value, the element is the first PHI in the
|
|
|
|
// linked list in CollisionMap.
|
|
|
|
DenseMap<uintptr_t, PHINode *> HashMap;
|
|
|
|
|
|
|
|
// Maintain linked lists of PHI nodes with common hash values.
|
|
|
|
DenseMap<PHINode *, PHINode *> CollisionMap;
|
|
|
|
|
|
|
|
// Examine each PHI.
|
|
|
|
for (BasicBlock::iterator I = BB->begin();
|
|
|
|
PHINode *PN = dyn_cast<PHINode>(I++); ) {
|
|
|
|
// Compute a hash value on the operands. Instcombine will likely have sorted
|
|
|
|
// them, which helps expose duplicates, but we have to check all the
|
|
|
|
// operands to be safe in case instcombine hasn't run.
|
|
|
|
uintptr_t Hash = 0;
|
2011-06-23 17:09:15 +08:00
|
|
|
// This hash algorithm is quite weak as hash functions go, but it seems
|
|
|
|
// to do a good enough job for this particular purpose, and is very quick.
|
2009-12-03 01:06:45 +08:00
|
|
|
for (User::op_iterator I = PN->op_begin(), E = PN->op_end(); I != E; ++I) {
|
|
|
|
Hash ^= reinterpret_cast<uintptr_t>(static_cast<Value *>(*I));
|
|
|
|
Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7));
|
|
|
|
}
|
2011-06-23 17:09:15 +08:00
|
|
|
for (PHINode::block_iterator I = PN->block_begin(), E = PN->block_end();
|
|
|
|
I != E; ++I) {
|
|
|
|
Hash ^= reinterpret_cast<uintptr_t>(static_cast<BasicBlock *>(*I));
|
|
|
|
Hash = (Hash << 7) | (Hash >> (sizeof(uintptr_t) * CHAR_BIT - 7));
|
|
|
|
}
|
2011-03-04 10:48:56 +08:00
|
|
|
// Avoid colliding with the DenseMap sentinels ~0 and ~0-1.
|
|
|
|
Hash >>= 1;
|
2009-12-03 01:06:45 +08:00
|
|
|
// If we've never seen this hash value before, it's a unique PHI.
|
|
|
|
std::pair<DenseMap<uintptr_t, PHINode *>::iterator, bool> Pair =
|
|
|
|
HashMap.insert(std::make_pair(Hash, PN));
|
|
|
|
if (Pair.second) continue;
|
|
|
|
// Otherwise it's either a duplicate or a hash collision.
|
|
|
|
for (PHINode *OtherPN = Pair.first->second; ; ) {
|
|
|
|
if (OtherPN->isIdenticalTo(PN)) {
|
|
|
|
// A duplicate. Replace this PHI with its duplicate.
|
|
|
|
PN->replaceAllUsesWith(OtherPN);
|
|
|
|
PN->eraseFromParent();
|
|
|
|
Changed = true;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
// A non-duplicate hash collision.
|
|
|
|
DenseMap<PHINode *, PHINode *>::iterator I = CollisionMap.find(OtherPN);
|
|
|
|
if (I == CollisionMap.end()) {
|
|
|
|
// Set this PHI to be the head of the linked list of colliding PHIs.
|
|
|
|
PHINode *Old = Pair.first->second;
|
|
|
|
Pair.first->second = PN;
|
|
|
|
CollisionMap[PN] = Old;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
// Procede to the next PHI in the list.
|
|
|
|
OtherPN = I->second;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
return Changed;
|
|
|
|
}
|
2010-12-26 04:37:57 +08:00
|
|
|
|
|
|
|
/// enforceKnownAlignment - If the specified pointer points to an object that
|
|
|
|
/// we control, modify the object's alignment to PrefAlign. This isn't
|
|
|
|
/// often possible though. If alignment is important, a more reliable approach
|
|
|
|
/// is to simply align all global variables and allocation instructions to
|
|
|
|
/// their preferred alignment from the beginning.
|
|
|
|
///
|
2010-12-31 06:34:44 +08:00
|
|
|
static unsigned enforceKnownAlignment(Value *V, unsigned Align,
|
2011-10-11 07:42:08 +08:00
|
|
|
unsigned PrefAlign, const TargetData *TD) {
|
2011-06-16 05:08:25 +08:00
|
|
|
V = V->stripPointerCasts();
|
2010-12-26 04:37:57 +08:00
|
|
|
|
2011-06-16 05:08:25 +08:00
|
|
|
if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) {
|
2011-10-11 07:42:08 +08:00
|
|
|
// If the preferred alignment is greater than the natural stack alignment
|
|
|
|
// then don't round up. This avoids dynamic stack realignment.
|
|
|
|
if (TD && TD->exceedsNaturalStackAlignment(PrefAlign))
|
|
|
|
return Align;
|
2010-12-26 04:37:57 +08:00
|
|
|
// If there is a requested alignment and if this is an alloca, round up.
|
|
|
|
if (AI->getAlignment() >= PrefAlign)
|
|
|
|
return AI->getAlignment();
|
|
|
|
AI->setAlignment(PrefAlign);
|
|
|
|
return PrefAlign;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (GlobalValue *GV = dyn_cast<GlobalValue>(V)) {
|
|
|
|
// If there is a large requested alignment and we can, bump up the alignment
|
|
|
|
// of the global.
|
|
|
|
if (GV->isDeclaration()) return Align;
|
2011-11-30 02:26:38 +08:00
|
|
|
// If the memory we set aside for the global may not be the memory used by
|
|
|
|
// the final program then it is impossible for us to reliably enforce the
|
|
|
|
// preferred alignment.
|
|
|
|
if (GV->isWeakForLinker()) return Align;
|
2010-12-26 04:37:57 +08:00
|
|
|
|
|
|
|
if (GV->getAlignment() >= PrefAlign)
|
|
|
|
return GV->getAlignment();
|
|
|
|
// We can only increase the alignment of the global if it has no alignment
|
|
|
|
// specified or if it is not assigned a section. If it is assigned a
|
|
|
|
// section, the global could be densely packed with other objects in the
|
|
|
|
// section, increasing the alignment could cause padding issues.
|
|
|
|
if (!GV->hasSection() || GV->getAlignment() == 0)
|
|
|
|
GV->setAlignment(PrefAlign);
|
|
|
|
return GV->getAlignment();
|
|
|
|
}
|
|
|
|
|
|
|
|
return Align;
|
|
|
|
}
|
|
|
|
|
|
|
|
/// getOrEnforceKnownAlignment - If the specified pointer has an alignment that
|
|
|
|
/// we can determine, return it, otherwise return 0. If PrefAlign is specified,
|
|
|
|
/// and it is more than the alignment of the ultimate object, see if we can
|
|
|
|
/// increase the alignment of the ultimate object, making this check succeed.
|
|
|
|
unsigned llvm::getOrEnforceKnownAlignment(Value *V, unsigned PrefAlign,
|
|
|
|
const TargetData *TD) {
|
|
|
|
assert(V->getType()->isPointerTy() &&
|
|
|
|
"getOrEnforceKnownAlignment expects a pointer!");
|
|
|
|
unsigned BitWidth = TD ? TD->getPointerSizeInBits() : 64;
|
|
|
|
APInt Mask = APInt::getAllOnesValue(BitWidth);
|
|
|
|
APInt KnownZero(BitWidth, 0), KnownOne(BitWidth, 0);
|
2010-12-26 04:52:04 +08:00
|
|
|
ComputeMaskedBits(V, Mask, KnownZero, KnownOne, TD);
|
2010-12-26 04:37:57 +08:00
|
|
|
unsigned TrailZ = KnownZero.countTrailingOnes();
|
|
|
|
|
|
|
|
// Avoid trouble with rediculously large TrailZ values, such as
|
|
|
|
// those computed from a null pointer.
|
|
|
|
TrailZ = std::min(TrailZ, unsigned(sizeof(unsigned) * CHAR_BIT - 1));
|
|
|
|
|
|
|
|
unsigned Align = 1u << std::min(BitWidth - 1, TrailZ);
|
|
|
|
|
|
|
|
// LLVM doesn't support alignments larger than this currently.
|
|
|
|
Align = std::min(Align, +Value::MaximumAlignment);
|
|
|
|
|
|
|
|
if (PrefAlign > Align)
|
2011-10-11 07:42:08 +08:00
|
|
|
Align = enforceKnownAlignment(V, Align, PrefAlign, TD);
|
2010-12-26 04:37:57 +08:00
|
|
|
|
|
|
|
// We don't need to make any adjustment.
|
|
|
|
return Align;
|
|
|
|
}
|
|
|
|
|
2011-03-18 05:58:19 +08:00
|
|
|
///===---------------------------------------------------------------------===//
|
|
|
|
/// Dbg Intrinsic utilities
|
|
|
|
///
|
|
|
|
|
|
|
|
/// Inserts a llvm.dbg.value instrinsic before the stores to an alloca'd value
|
|
|
|
/// that has an associated llvm.dbg.decl intrinsic.
|
|
|
|
bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
|
|
|
|
StoreInst *SI, DIBuilder &Builder) {
|
|
|
|
DIVariable DIVar(DDI->getVariable());
|
|
|
|
if (!DIVar.Verify())
|
|
|
|
return false;
|
|
|
|
|
2011-05-17 05:24:05 +08:00
|
|
|
Instruction *DbgVal = NULL;
|
|
|
|
// If an argument is zero extended then use argument directly. The ZExt
|
|
|
|
// may be zapped by an optimization pass in future.
|
|
|
|
Argument *ExtendedArg = NULL;
|
|
|
|
if (ZExtInst *ZExt = dyn_cast<ZExtInst>(SI->getOperand(0)))
|
|
|
|
ExtendedArg = dyn_cast<Argument>(ZExt->getOperand(0));
|
|
|
|
if (SExtInst *SExt = dyn_cast<SExtInst>(SI->getOperand(0)))
|
|
|
|
ExtendedArg = dyn_cast<Argument>(SExt->getOperand(0));
|
|
|
|
if (ExtendedArg)
|
|
|
|
DbgVal = Builder.insertDbgValueIntrinsic(ExtendedArg, 0, DIVar, SI);
|
|
|
|
else
|
|
|
|
DbgVal = Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar, SI);
|
|
|
|
|
2011-03-18 05:58:19 +08:00
|
|
|
// Propagate any debug metadata from the store onto the dbg.value.
|
|
|
|
DebugLoc SIDL = SI->getDebugLoc();
|
|
|
|
if (!SIDL.isUnknown())
|
|
|
|
DbgVal->setDebugLoc(SIDL);
|
|
|
|
// Otherwise propagate debug metadata from dbg.declare.
|
|
|
|
else
|
|
|
|
DbgVal->setDebugLoc(DDI->getDebugLoc());
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
2011-03-19 07:45:43 +08:00
|
|
|
/// Inserts a llvm.dbg.value instrinsic before the stores to an alloca'd value
|
|
|
|
/// that has an associated llvm.dbg.decl intrinsic.
|
|
|
|
bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
|
|
|
|
LoadInst *LI, DIBuilder &Builder) {
|
|
|
|
DIVariable DIVar(DDI->getVariable());
|
|
|
|
if (!DIVar.Verify())
|
|
|
|
return false;
|
|
|
|
|
|
|
|
Instruction *DbgVal =
|
|
|
|
Builder.insertDbgValueIntrinsic(LI->getOperand(0), 0,
|
|
|
|
DIVar, LI);
|
|
|
|
|
|
|
|
// Propagate any debug metadata from the store onto the dbg.value.
|
|
|
|
DebugLoc LIDL = LI->getDebugLoc();
|
|
|
|
if (!LIDL.isUnknown())
|
|
|
|
DbgVal->setDebugLoc(LIDL);
|
|
|
|
// Otherwise propagate debug metadata from dbg.declare.
|
|
|
|
else
|
|
|
|
DbgVal->setDebugLoc(DDI->getDebugLoc());
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
2011-03-18 06:18:16 +08:00
|
|
|
/// LowerDbgDeclare - Lowers llvm.dbg.declare intrinsics into appropriate set
|
|
|
|
/// of llvm.dbg.value intrinsics.
|
|
|
|
bool llvm::LowerDbgDeclare(Function &F) {
|
|
|
|
DIBuilder DIB(*F.getParent());
|
|
|
|
SmallVector<DbgDeclareInst *, 4> Dbgs;
|
|
|
|
for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
|
|
|
|
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end(); BI != BE; ++BI) {
|
|
|
|
if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(BI))
|
|
|
|
Dbgs.push_back(DDI);
|
|
|
|
}
|
|
|
|
if (Dbgs.empty())
|
|
|
|
return false;
|
|
|
|
|
|
|
|
for (SmallVector<DbgDeclareInst *, 4>::iterator I = Dbgs.begin(),
|
|
|
|
E = Dbgs.end(); I != E; ++I) {
|
|
|
|
DbgDeclareInst *DDI = *I;
|
|
|
|
if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(DDI->getAddress())) {
|
2011-04-29 04:32:02 +08:00
|
|
|
bool RemoveDDI = true;
|
2011-03-18 06:18:16 +08:00
|
|
|
for (Value::use_iterator UI = AI->use_begin(), E = AI->use_end();
|
|
|
|
UI != E; ++UI)
|
|
|
|
if (StoreInst *SI = dyn_cast<StoreInst>(*UI))
|
|
|
|
ConvertDebugDeclareToDebugValue(DDI, SI, DIB);
|
2011-03-19 07:45:43 +08:00
|
|
|
else if (LoadInst *LI = dyn_cast<LoadInst>(*UI))
|
|
|
|
ConvertDebugDeclareToDebugValue(DDI, LI, DIB);
|
2011-04-29 04:32:02 +08:00
|
|
|
else
|
|
|
|
RemoveDDI = false;
|
|
|
|
if (RemoveDDI)
|
|
|
|
DDI->eraseFromParent();
|
2011-03-18 06:18:16 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
return true;
|
|
|
|
}
|
2011-05-24 11:10:43 +08:00
|
|
|
|
|
|
|
/// FindAllocaDbgDeclare - Finds the llvm.dbg.declare intrinsic describing the
|
|
|
|
/// alloca 'V', if any.
|
|
|
|
DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
|
|
|
|
if (MDNode *DebugNode = MDNode::getIfExists(V->getContext(), V))
|
|
|
|
for (Value::use_iterator UI = DebugNode->use_begin(),
|
|
|
|
E = DebugNode->use_end(); UI != E; ++UI)
|
|
|
|
if (DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(*UI))
|
|
|
|
return DDI;
|
|
|
|
|
|
|
|
return 0;
|
|
|
|
}
|