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improve DEBUG's a bit, switch to eraseFromParent() to simplify

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code a bit, switch from constant folding to instsimplify.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121751 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2010-12-14 06:17:25 +00:00
parent 8168efffa7
commit 302ba6fc1c
1 changed files with 28 additions and 26 deletions
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52
lib/Transforms/Utils/SimplifyCFG.cpp
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@ -19,10 +19,7 @@
#include "llvm/Type.h" #include "llvm/Type.h"
#include "llvm/DerivedTypes.h" #include "llvm/DerivedTypes.h"
#include "llvm/GlobalVariable.h" #include "llvm/GlobalVariable.h"
#include "llvm/Support/CFG.h" #include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Target/TargetData.h" #include "llvm/Target/TargetData.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h" #include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/DenseMap.h"
@ -30,6 +27,9 @@
#include "llvm/ADT/SmallPtrSet.h" #include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h" #include "llvm/ADT/Statistic.h"
#include "llvm/ADT/STLExtras.h" #include "llvm/ADT/STLExtras.h"
#include "llvm/Support/CFG.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm> #include <algorithm>
#include <set> #include <set>
#include <map> #include <map>
@ -796,7 +796,7 @@ static bool HoistThenElseCodeToIf(BranchInst *BI) {
if (!I2->use_empty()) if (!I2->use_empty())
I2->replaceAllUsesWith(I1); I2->replaceAllUsesWith(I1);
I1->intersectOptionalDataWith(I2); I1->intersectOptionalDataWith(I2);
BB2->getInstList().erase(I2); I2->eraseFromParent();
I1 = BB1_Itr++; I1 = BB1_Itr++;
while (isa<DbgInfoIntrinsic>(I1)) while (isa<DbgInfoIntrinsic>(I1))
@ -1050,7 +1050,7 @@ static bool BlockIsSimpleEnoughToThreadThrough(BasicBlock *BB) {
/// that is defined in the same block as the branch and if any PHI entries are /// that is defined in the same block as the branch and if any PHI entries are
/// constants, thread edges corresponding to that entry to be branches to their /// constants, thread edges corresponding to that entry to be branches to their
/// ultimate destination. /// ultimate destination.
static bool FoldCondBranchOnPHI(BranchInst *BI) { static bool FoldCondBranchOnPHI(BranchInst *BI, const TargetData *TD) {
BasicBlock *BB = BI->getParent(); BasicBlock *BB = BI->getParent();
PHINode *PN = dyn_cast<PHINode>(BI->getCondition()); PHINode *PN = dyn_cast<PHINode>(BI->getCondition());
// NOTE: we currently cannot transform this case if the PHI node is used // NOTE: we currently cannot transform this case if the PHI node is used
@ -1118,9 +1118,9 @@ static bool FoldCondBranchOnPHI(BranchInst *BI) {
} }
// Check for trivial simplification. // Check for trivial simplification.
if (Constant *C = ConstantFoldInstruction(N)) { if (Value *V = SimplifyInstruction(N, TD)) {
TranslateMap[BBI] = C; TranslateMap[BBI] = V;
delete N; // Constant folded away, don't need actual inst delete N; // Instruction folded away, don't need actual inst
} else { } else {
// Insert the new instruction into its new home. // Insert the new instruction into its new home.
EdgeBB->getInstList().insert(InsertPt, N); EdgeBB->getInstList().insert(InsertPt, N);
@ -1139,7 +1139,7 @@ static bool FoldCondBranchOnPHI(BranchInst *BI) {
} }
// Recurse, simplifying any other constants. // Recurse, simplifying any other constants.
return FoldCondBranchOnPHI(BI) | true; return FoldCondBranchOnPHI(BI, TD) | true;
} }
return false; return false;
@ -1251,7 +1251,7 @@ static bool FoldTwoEntryPHINode(PHINode *PN) {
PN->replaceAllUsesWith(NV); PN->replaceAllUsesWith(NV);
NV->takeName(PN); NV->takeName(PN);
BB->getInstList().erase(PN); PN->eraseFromParent();
} }
return true; return true;
} }
@ -1779,7 +1779,8 @@ static bool SimplifyIndirectBrOnSelect(IndirectBrInst *IBI, SelectInst *SI) {
/// ///
/// We prefer to split the edge to 'end' so that there is a true/false entry to /// We prefer to split the edge to 'end' so that there is a true/false entry to
/// the PHI, merging the third icmp into the switch. /// the PHI, merging the third icmp into the switch.
static bool TryToSimplifyUncondBranchWithICmpInIt(ICmpInst *ICI) { static bool TryToSimplifyUncondBranchWithICmpInIt(ICmpInst *ICI,
const TargetData *TD) {
BasicBlock *BB = ICI->getParent(); BasicBlock *BB = ICI->getParent();
// If the block has any PHIs in it or the icmp has multiple uses, it is too // If the block has any PHIs in it or the icmp has multiple uses, it is too
// complex. // complex.
@ -1806,8 +1807,8 @@ static bool TryToSimplifyUncondBranchWithICmpInIt(ICmpInst *ICI) {
assert(VVal && "Should have a unique destination value"); assert(VVal && "Should have a unique destination value");
ICI->setOperand(0, VVal); ICI->setOperand(0, VVal);
if (Constant *C = ConstantFoldInstruction(ICI)) { if (Value *V = SimplifyInstruction(ICI, TD)) {
ICI->replaceAllUsesWith(C); ICI->replaceAllUsesWith(V);
ICI->eraseFromParent(); ICI->eraseFromParent();
} }
// BB is now empty, so it is likely to simplify away. // BB is now empty, so it is likely to simplify away.
@ -1905,16 +1906,13 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, const TargetData *TD) {
BasicBlock *BB = BI->getParent(); BasicBlock *BB = BI->getParent();
DEBUG(dbgs() << "CONVERTING 'icmp' CHAIN with " << Values.size() DEBUG(dbgs() << "Converting 'icmp' chain with " << Values.size()
<< " cases into SWITCH. BB is:\n" << *BB); << " cases into SWITCH. BB is:\n" << *BB);
// If there are any extra values that couldn't be folded into the switch // If there are any extra values that couldn't be folded into the switch
// then we evaluate them with an explicit branch first. Split the block // then we evaluate them with an explicit branch first. Split the block
// right before the condbr to handle it. // right before the condbr to handle it.
if (ExtraCase) { if (ExtraCase) {
DEBUG(dbgs() << " ** 'icmp' chain unhandled condition: " << *ExtraCase
<< '\n');
BasicBlock *NewBB = BB->splitBasicBlock(BI, "switch.early.test"); BasicBlock *NewBB = BB->splitBasicBlock(BI, "switch.early.test");
// Remove the uncond branch added to the old block. // Remove the uncond branch added to the old block.
TerminatorInst *OldTI = BB->getTerminator(); TerminatorInst *OldTI = BB->getTerminator();
@ -1932,6 +1930,9 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, const TargetData *TD) {
PHINode *PN = cast<PHINode>(I); PHINode *PN = cast<PHINode>(I);
PN->addIncoming(PN->getIncomingValueForBlock(NewBB), BB); PN->addIncoming(PN->getIncomingValueForBlock(NewBB), BB);
} }
DEBUG(dbgs() << " ** 'icmp' chain unhandled condition: " << *ExtraCase
<< "\nEXTRABB = " << *BB);
BB = NewBB; BB = NewBB;
} }
@ -1964,6 +1965,7 @@ static bool SimplifyBranchOnICmpChain(BranchInst *BI, const TargetData *TD) {
// Erase the old branch instruction. // Erase the old branch instruction.
EraseTerminatorInstAndDCECond(BI); EraseTerminatorInstAndDCECond(BI);
DEBUG(dbgs() << " ** 'icmp' chain result is:\n" << *BB << '\n');
return true; return true;
} }
@ -2007,7 +2009,7 @@ bool SimplifyCFGOpt::SimplifyReturn(ReturnInst *RI) {
// Update any PHI nodes in the returning block to realize that we no // Update any PHI nodes in the returning block to realize that we no
// longer branch to them. // longer branch to them.
BB->removePredecessor(Pred); BB->removePredecessor(Pred);
Pred->getInstList().erase(UncondBranch); UncondBranch->eraseFromParent();
} }
// If we eliminated all predecessors of the block, delete the block now. // If we eliminated all predecessors of the block, delete the block now.
@ -2101,7 +2103,7 @@ bool SimplifyCFGOpt::SimplifyUnreachable(UnreachableInst *UI) {
break; break;
// Delete this instruction // Delete this instruction
BB->getInstList().erase(BBI); BBI->eraseFromParent();
Changed = true; Changed = true;
} }
@ -2286,7 +2288,7 @@ bool SimplifyCFGOpt::SimplifyUncondBranch(BranchInst *BI) {
if (ICI->isEquality() && isa<ConstantInt>(ICI->getOperand(1))) { if (ICI->isEquality() && isa<ConstantInt>(ICI->getOperand(1))) {
for (++I; isa<DbgInfoIntrinsic>(I); ++I) for (++I; isa<DbgInfoIntrinsic>(I); ++I)
; ;
if (I->isTerminator() && TryToSimplifyUncondBranchWithICmpInIt(ICI)) if (I->isTerminator() && TryToSimplifyUncondBranchWithICmpInIt(ICI, TD))
return true; return true;
} }
@ -2360,7 +2362,7 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI) {
// through this block if any PHI node entries are constants. // through this block if any PHI node entries are constants.
if (PHINode *PN = dyn_cast<PHINode>(BI->getCondition())) if (PHINode *PN = dyn_cast<PHINode>(BI->getCondition()))
if (PN->getParent() == BI->getParent()) if (PN->getParent() == BI->getParent())
if (FoldCondBranchOnPHI(BI)) if (FoldCondBranchOnPHI(BI, TD))
return SimplifyCFG(BB) | true; return SimplifyCFG(BB) | true;
// If this basic block is ONLY a setcc and a branch, and if a predecessor // If this basic block is ONLY a setcc and a branch, and if a predecessor
@ -2381,14 +2383,14 @@ bool SimplifyCFGOpt::SimplifyCondBranch(BranchInst *BI) {
bool SimplifyCFGOpt::run(BasicBlock *BB) { bool SimplifyCFGOpt::run(BasicBlock *BB) {
bool Changed = false; bool Changed = false;
Function *Fn = BB->getParent();
assert(BB && Fn && "Block not embedded in function!"); assert(BB && BB->getParent() && "Block not embedded in function!");
assert(BB->getTerminator() && "Degenerate basic block encountered!"); assert(BB->getTerminator() && "Degenerate basic block encountered!");
// Remove basic blocks that have no predecessors (except the entry block)... // Remove basic blocks that have no predecessors (except the entry block)...
// or that just have themself as a predecessor. These are unreachable. // or that just have themself as a predecessor. These are unreachable.
if ((pred_begin(BB) == pred_end(BB) && BB != &Fn->getEntryBlock()) || if ((pred_begin(BB) == pred_end(BB) &&
BB != &BB->getParent()->getEntryBlock()) ||
BB->getSinglePredecessor() == BB) { BB->getSinglePredecessor() == BB) {
DEBUG(dbgs() << "Removing BB: \n" << *BB); DEBUG(dbgs() << "Removing BB: \n" << *BB);
DeleteDeadBlock(BB); DeleteDeadBlock(BB);