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Re-apply 85799. It turns out my code isn't buggy.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85947 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2009-11-03 21:40:02 +00:00
parent 60faaf64b4
commit 777c6b7caa
3 changed files with 52 additions and 21 deletions
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63
lib/CodeGen/MachineLICM.cpp
View File

@ -56,12 +56,12 @@ namespace {
// State that is updated as we process loops
bool Changed; // True if a loop is changed.
bool FirstInLoop; // True if it's the first LICM in the loop.
MachineLoop *CurLoop; // The current loop we are working on.
MachineBasicBlock *CurPreheader; // The preheader for CurLoop.
// For each BB and opcode pair, keep a list of hoisted instructions.
DenseMap<std::pair<unsigned, unsigned>,
std::vector<const MachineInstr*> > CSEMap;
// For each opcode, keep a list of potentail CSE instructions.
DenseMap<unsigned, std::vector<const MachineInstr*> > CSEMap;
public:
static char ID; // Pass identification, replacement for typeid
MachineLICM() : MachineFunctionPass(&ID) {}
@ -115,6 +115,11 @@ namespace {
/// that is safe to hoist, this instruction is called to do the dirty work.
///
void Hoist(MachineInstr *MI);
/// InitCSEMap - Initialize the CSE map with instructions that are in the
/// current loop preheader that may become duplicates of instructions that
/// are hoisted out of the loop.
void InitCSEMap(MachineBasicBlock *BB);
};
} // end anonymous namespace
@ -140,7 +145,7 @@ static bool LoopIsOuterMostWithPreheader(MachineLoop *CurLoop) {
bool MachineLICM::runOnMachineFunction(MachineFunction &MF) {
DEBUG(errs() << "******** Machine LICM ********\n");
Changed = false;
Changed = FirstInLoop = false;
TM = &MF.getTarget();
TII = TM->getInstrInfo();
TRI = TM->getRegisterInfo();
@ -152,8 +157,7 @@ bool MachineLICM::runOnMachineFunction(MachineFunction &MF) {
DT = &getAnalysis<MachineDominatorTree>();
AA = &getAnalysis<AliasAnalysis>();
for (MachineLoopInfo::iterator
I = LI->begin(), E = LI->end(); I != E; ++I) {
for (MachineLoopInfo::iterator I = LI->begin(), E = LI->end(); I != E; ++I) {
CurLoop = *I;
// Only visit outer-most preheader-sporting loops.
@ -170,7 +174,11 @@ bool MachineLICM::runOnMachineFunction(MachineFunction &MF) {
if (!CurPreheader)
continue;
// CSEMap is initialized for loop header when the first instruction is
// being hoisted.
FirstInLoop = true;
HoistRegion(DT->getNode(CurLoop->getHeader()));
CSEMap.clear();
}
return Changed;
@ -191,10 +199,7 @@ void MachineLICM::HoistRegion(MachineDomTreeNode *N) {
for (MachineBasicBlock::iterator
MII = BB->begin(), E = BB->end(); MII != E; ) {
MachineBasicBlock::iterator NextMII = MII; ++NextMII;
MachineInstr &MI = *MII;
Hoist(&MI);
Hoist(&*MII);
MII = NextMII;
}
@ -430,6 +435,27 @@ MachineInstr *MachineLICM::ExtractHoistableLoad(MachineInstr *MI) {
return NewMIs[0];
}
void MachineLICM::InitCSEMap(MachineBasicBlock *BB) {
for (MachineBasicBlock::iterator I = BB->begin(),E = BB->end(); I != E; ++I) {
const MachineInstr *MI = &*I;
// FIXME: For now, only hoist re-materilizable instructions. LICM will
// increase register pressure. We want to make sure it doesn't increase
// spilling.
if (TII->isTriviallyReMaterializable(MI, AA)) {
unsigned Opcode = MI->getOpcode();
DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator
CI = CSEMap.find(Opcode);
if (CI != CSEMap.end())
CI->second.push_back(MI);
else {
std::vector<const MachineInstr*> CSEMIs;
CSEMIs.push_back(MI);
CSEMap.insert(std::make_pair(Opcode, CSEMIs));
}
}
}
}
/// Hoist - When an instruction is found to use only loop invariant operands
/// that are safe to hoist, this instruction is called to do the dirty work.
///
@ -454,11 +480,14 @@ void MachineLICM::Hoist(MachineInstr *MI) {
errs() << "\n";
});
// If this is the first instruction being hoisted to the preheader,
// initialize the CSE map with potential common expressions.
InitCSEMap(CurPreheader);
// Look for opportunity to CSE the hoisted instruction.
std::pair<unsigned, unsigned> BBOpcPair =
std::make_pair(CurPreheader->getNumber(), MI->getOpcode());
DenseMap<std::pair<unsigned, unsigned>,
std::vector<const MachineInstr*> >::iterator CI = CSEMap.find(BBOpcPair);
unsigned Opcode = MI->getOpcode();
DenseMap<unsigned, std::vector<const MachineInstr*> >::iterator
CI = CSEMap.find(Opcode);
bool DoneCSE = false;
if (CI != CSEMap.end()) {
const MachineInstr *Dup = LookForDuplicate(MI, CI->second, RegInfo);
@ -477,15 +506,15 @@ void MachineLICM::Hoist(MachineInstr *MI) {
// Otherwise, splice the instruction to the preheader.
if (!DoneCSE) {
CurPreheader->splice(CurPreheader->getFirstTerminator(),
MI->getParent(), MI);
CurPreheader->splice(CurPreheader->getFirstTerminator(),MI->getParent(),MI);
// Add to the CSE map.
if (CI != CSEMap.end())
CI->second.push_back(MI);
else {
std::vector<const MachineInstr*> CSEMIs;
CSEMIs.push_back(MI);
CSEMap.insert(std::make_pair(BBOpcPair, CSEMIs));
CSEMap.insert(std::make_pair(Opcode, CSEMIs));
}
}

2
test/CodeGen/ARM/remat.ll
View File

@ -1,5 +1,5 @@
; RUN: llc < %s -mtriple=arm-apple-darwin
; RUN: llc < %s -mtriple=arm-apple-darwin -stats -info-output-file - | grep "Number of re-materialization" | grep 4
; RUN: llc < %s -mtriple=arm-apple-darwin -stats -info-output-file - | grep "Number of re-materialization" | grep 5
%struct.CONTENTBOX = type { i32, i32, i32, i32, i32 }
%struct.LOCBOX = type { i32, i32, i32, i32 }

8
test/CodeGen/X86/2007-11-30-LoadFolding-Bug.ll
View File

@ -1,6 +1,5 @@
; RUN: llc < %s -march=x86 -mattr=+sse2 -stats |& \
; RUN: grep {1 .*folded into instructions}
; Increment in loop bb.128.i adjusted to 2, to prevent loop reversal from
; RUN: llc < %s -march=x86 -mattr=+sse2 | FileCheck %s
; Increment in loop bb.i28.i adjusted to 2, to prevent loop reversal from
; kicking in.
declare fastcc void @rdft(i32, i32, double*, i32*, double*)
@ -34,6 +33,9 @@ cond_next36.i: ; preds = %cond_next.i
br label %bb.i28.i
bb.i28.i: ; preds = %bb.i28.i, %cond_next36.i
; CHECK: %bb.i28.i
; CHECK: addl $2
; CHECK: addl $2
%j.0.reg2mem.0.i16.i = phi i32 [ 0, %cond_next36.i ], [ %indvar.next39.i, %bb.i28.i ] ; <i32> [#uses=2]
%din_addr.1.reg2mem.0.i17.i = phi double [ 0.000000e+00, %cond_next36.i ], [ %tmp16.i25.i, %bb.i28.i ] ; <double> [#uses=1]
%tmp1.i18.i = fptosi double %din_addr.1.reg2mem.0.i17.i to i32 ; <i32> [#uses=2]