Reapply r55191 and r55192.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55205 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman
2008-08-22 21:28:19 +00:00
parent 70f24c62ad
commit 3c8f36fd03
3 changed files with 18 additions and 9 deletions

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@ -17,6 +17,7 @@
#include "llvm/BasicBlock.h" #include "llvm/BasicBlock.h"
#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/DenseMap.h"
#include "llvm/CodeGen/SelectionDAGNodes.h" #include "llvm/CodeGen/SelectionDAGNodes.h"
#include <map>
namespace llvm { namespace llvm {
@ -52,6 +53,7 @@ public:
BasicBlock::iterator BasicBlock::iterator
SelectInstructions(BasicBlock::iterator Begin, BasicBlock::iterator End, SelectInstructions(BasicBlock::iterator Begin, BasicBlock::iterator End,
DenseMap<const Value*, unsigned> &ValueMap, DenseMap<const Value*, unsigned> &ValueMap,
std::map<const BasicBlock*, MachineBasicBlock *> &MBBMap,
MachineBasicBlock *MBB); MachineBasicBlock *MBB);
virtual ~FastISel(); virtual ~FastISel();

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@ -145,6 +145,8 @@ BasicBlock::iterator
FastISel::SelectInstructions(BasicBlock::iterator Begin, FastISel::SelectInstructions(BasicBlock::iterator Begin,
BasicBlock::iterator End, BasicBlock::iterator End,
DenseMap<const Value*, unsigned> &ValueMap, DenseMap<const Value*, unsigned> &ValueMap,
std::map<const BasicBlock*,
MachineBasicBlock *> &MBBMap,
MachineBasicBlock *mbb) { MachineBasicBlock *mbb) {
MBB = mbb; MBB = mbb;
BasicBlock::iterator I = Begin; BasicBlock::iterator I = Begin;
@ -195,19 +197,24 @@ FastISel::SelectInstructions(BasicBlock::iterator Begin,
case Instruction::Br: { case Instruction::Br: {
BranchInst *BI = cast<BranchInst>(I); BranchInst *BI = cast<BranchInst>(I);
// For now, check for and handle just the most trivial case: an
// unconditional fall-through branch.
if (BI->isUnconditional()) { if (BI->isUnconditional()) {
MachineFunction::iterator NextMBB = MachineFunction::iterator NextMBB =
next(MachineFunction::iterator(MBB)); next(MachineFunction::iterator(MBB));
if (NextMBB != MF.end() && BasicBlock *LLVMSucc = BI->getSuccessor(0);
NextMBB->getBasicBlock() == BI->getSuccessor(0)) { MachineBasicBlock *MSucc = MBBMap[LLVMSucc];
MBB->addSuccessor(NextMBB);
break; if (NextMBB != MF.end() && MSucc == NextMBB) {
// The unconditional fall-through case, which needs no instructions.
} else {
// The unconditional branch case.
TII.InsertBranch(*MBB, MSucc, NULL, SmallVector<MachineOperand, 0>());
} }
MBB->addSuccessor(MSucc);
break;
} }
// Something more complicated. Halt "fast" selection and bail. // Conditional branches are not handed yet.
// Halt "fast" selection and bail.
return I; return I;
} }

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@ -5113,7 +5113,7 @@ void SelectionDAGISel::BuildSelectionDAG(SelectionDAG &DAG, BasicBlock *LLVMBB,
cast<BranchInst>(LLVMBB->getTerminator())->isUnconditional()) { cast<BranchInst>(LLVMBB->getTerminator())->isUnconditional()) {
if (FastISel *F = TLI.createFastISel(FuncInfo.MF)) { if (FastISel *F = TLI.createFastISel(FuncInfo.MF)) {
Begin = F->SelectInstructions(Begin, LLVMBB->end(), Begin = F->SelectInstructions(Begin, LLVMBB->end(),
FuncInfo.ValueMap, BB); FuncInfo.ValueMap, FuncInfo.MBBMap, BB);
// Clean up the FastISel object. TODO: Reorganize what data is // Clean up the FastISel object. TODO: Reorganize what data is
// stored in the FastISel class itself and what is merely passed // stored in the FastISel class itself and what is merely passed