Enable two-address remat by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52701 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2008-06-25 01:16:38 +00:00
parent e4f6ee590b
commit 601ca4b434
4 changed files with 102 additions and 37 deletions

View File

@ -53,10 +53,6 @@ STATISTIC(NumConvertedTo3Addr, "Number of instructions promoted to 3-address");
STATISTIC(Num3AddrSunk, "Number of 3-address instructions sunk");
STATISTIC(NumReMats, "Number of instructions re-materialized");
static cl::opt<bool>
EnableReMat("two-addr-remat", cl::init(false), cl::Hidden,
cl::desc("Two-addr conversion should remat when possible."));
namespace {
class VISIBILITY_HIDDEN TwoAddressInstructionPass
: public MachineFunctionPass {
@ -71,8 +67,8 @@ namespace {
bool isSafeToReMat(unsigned DstReg, MachineInstr *MI);
bool isProfitableToReMat(unsigned Reg, const TargetRegisterClass *RC,
MachineInstr *MI, unsigned Loc,
MachineInstr *DefMI, MachineBasicBlock *MBB,
MachineInstr *MI, MachineInstr *DefMI,
MachineBasicBlock *MBB, unsigned Loc,
DenseMap<MachineInstr*, unsigned> &DistanceMap);
public:
static char ID; // Pass identification, replacement for typeid
@ -248,12 +244,9 @@ static bool isTwoAddrUse(MachineInstr *UseMI, unsigned Reg) {
bool
TwoAddressInstructionPass::isProfitableToReMat(unsigned Reg,
const TargetRegisterClass *RC,
MachineInstr *MI, unsigned Loc,
MachineInstr *DefMI, MachineBasicBlock *MBB,
DenseMap<MachineInstr*, unsigned> &DistanceMap) {
if (DefMI->getParent() != MBB)
return true;
// If earlier uses in MBB are not two-address uses, then don't remat.
MachineInstr *MI, MachineInstr *DefMI,
MachineBasicBlock *MBB, unsigned Loc,
DenseMap<MachineInstr*, unsigned> &DistanceMap){
bool OtherUse = false;
for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
UE = MRI->use_end(); UI != UE; ++UI) {
@ -261,18 +254,26 @@ TwoAddressInstructionPass::isProfitableToReMat(unsigned Reg,
if (!UseMO.isUse())
continue;
MachineInstr *UseMI = UseMO.getParent();
if (UseMI->getParent() != MBB)
continue;
DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI);
if (DI != DistanceMap.end() && DI->second == Loc)
continue; // Current use.
OtherUse = true;
// There is at least one other use in the MBB that will clobber the
// register.
if (isTwoAddrUse(UseMI, Reg))
return true;
MachineBasicBlock *UseMBB = UseMI->getParent();
if (UseMBB == MBB) {
DenseMap<MachineInstr*, unsigned>::iterator DI = DistanceMap.find(UseMI);
if (DI != DistanceMap.end() && DI->second == Loc)
continue; // Current use.
OtherUse = true;
// There is at least one other use in the MBB that will clobber the
// register.
if (isTwoAddrUse(UseMI, Reg))
return true;
}
}
return !OtherUse;
// If other uses in MBB are not two-address uses, then don't remat.
if (OtherUse)
return false;
// No other uses in the same block, remat if it's defined in the same
// block so it does not unnecessarily extend the live range.
return MBB == DefMI->getParent();
}
/// runOnMachineFunction - Reduce two-address instructions to two operands.
@ -428,9 +429,9 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
MachineInstr *DefMI = MRI->getVRegDef(regB);
// If it's safe and profitable, remat the definition instead of
// copying it.
if (EnableReMat && DefMI &&
if (DefMI &&
isSafeToReMat(regB, DefMI) &&
isProfitableToReMat(regB, rc, mi, Dist, DefMI, mbbi,DistanceMap)){
isProfitableToReMat(regB, rc, mi, DefMI, mbbi, Dist,DistanceMap)){
DEBUG(cerr << "2addr: REMATTING : " << *DefMI << "\n");
TII->reMaterialize(*mbbi, mi, regA, DefMI);
ReMatRegs.set(regB);
@ -473,17 +474,14 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
}
}
if (EnableReMat) {
// Some remat'ed instructions are dead.
int VReg = ReMatRegs.find_first();
while (VReg != -1) {
if (MRI->use_empty(VReg)) {
MachineInstr *DefMI = MRI->getVRegDef(VReg);
DefMI->eraseFromParent();
}
VReg = ReMatRegs.find_next(VReg);
// Some remat'ed instructions are dead.
int VReg = ReMatRegs.find_first();
while (VReg != -1) {
if (MRI->use_empty(VReg)) {
MachineInstr *DefMI = MRI->getVRegDef(VReg);
DefMI->eraseFromParent();
}
VReg = ReMatRegs.find_next(VReg);
}
return MadeChange;

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@ -199,7 +199,7 @@ let neverHasSideEffects = 1 in
def MOV64rr : RI<0x89, MRMDestReg, (outs GR64:$dst), (ins GR64:$src),
"mov{q}\t{$src, $dst|$dst, $src}", []>;
let isReMaterializable = 1 in {
let isReMaterializable = 1, isAsCheapAsAMove = 1 in {
def MOV64ri : RIi64<0xB8, AddRegFrm, (outs GR64:$dst), (ins i64imm:$src),
"movabs{q}\t{$src, $dst|$dst, $src}",
[(set GR64:$dst, imm:$src)]>;

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@ -3,7 +3,7 @@
declare fastcc void @rdft(i32, i32, double*, i32*, double*)
define fastcc void @mp_sqrt(i32 %n, i32 %radix, i32* %in, i32* %out, i32* %tmp1, i32* %tmp2, i32 %nfft, double* %tmp1fft, double* %tmp2fft, i32* %ip, double* %w) {
define fastcc void @mp_sqrt(i32 %n, i32 %radix, i32* %in, i32* %out, i32* %tmp1, i32* %tmp2, i32 %nfft, double* %tmp1fft, double* %tmp2fft, i32* %ip, double* %w) nounwind {
entry:
br label %bb.i5

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@ -0,0 +1,67 @@
; RUN: llvm-as < %s | llc -march=x86 | grep 59796 | count 3
%Args = type %Value*
%Exec = type opaque*
%Identifier = type opaque*
%JSFunction = type %Value (%Exec, %Scope, %Value, %Args)
%PropertyNameArray = type opaque*
%Scope = type opaque*
%Value = type opaque*
declare i1 @X1(%Exec) readonly
declare %Value @X2(%Exec)
declare i32 @X3(%Exec, %Value)
declare %Value @X4(i32) readnone
define internal %Value @fast3bitlookup(%Exec %exec, %Scope %scope, %Value %this, %Args %args) nounwind {
prologue:
%eh_check = tail call i1 @X1( %Exec %exec ) readonly ; <i1> [#uses=1]
br i1 %eh_check, label %exception, label %no_exception
exception: ; preds = %no_exception, %prologue
%rethrow_result = tail call %Value @X2( %Exec %exec ) ; <%Value> [#uses=1]
ret %Value %rethrow_result
no_exception: ; preds = %prologue
%args_intptr = bitcast %Args %args to i32* ; <i32*> [#uses=1]
%argc_val = load i32* %args_intptr ; <i32> [#uses=1]
%cmpParamArgc = icmp sgt i32 %argc_val, 0 ; <i1> [#uses=1]
%arg_ptr = getelementptr %Args %args, i32 1 ; <%Args> [#uses=1]
%arg_val = load %Args %arg_ptr ; <%Value> [#uses=1]
%ext_arg_val = select i1 %cmpParamArgc, %Value %arg_val, %Value inttoptr (i32 5 to %Value) ; <%Value> [#uses=1]
%toInt325 = tail call i32 @X3( %Exec %exec, %Value %ext_arg_val ) ; <i32> [#uses=3]
%eh_check6 = tail call i1 @X1( %Exec %exec ) readonly ; <i1> [#uses=1]
br i1 %eh_check6, label %exception, label %no_exception7
no_exception7: ; preds = %no_exception
%shl_tmp_result = shl i32 %toInt325, 1 ; <i32> [#uses=1]
%rhs_masked13 = and i32 %shl_tmp_result, 14 ; <i32> [#uses=1]
%ashr_tmp_result = lshr i32 59796, %rhs_masked13 ; <i32> [#uses=1]
%and_tmp_result15 = and i32 %ashr_tmp_result, 3 ; <i32> [#uses=1]
%ashr_tmp_result3283 = lshr i32 %toInt325, 2 ; <i32> [#uses=1]
%rhs_masked38 = and i32 %ashr_tmp_result3283, 14 ; <i32> [#uses=1]
%ashr_tmp_result39 = lshr i32 59796, %rhs_masked38 ; <i32> [#uses=1]
%and_tmp_result41 = and i32 %ashr_tmp_result39, 3 ; <i32> [#uses=1]
%addconv = add i32 %and_tmp_result15, %and_tmp_result41 ; <i32> [#uses=1]
%ashr_tmp_result6181 = lshr i32 %toInt325, 5 ; <i32> [#uses=1]
%rhs_masked67 = and i32 %ashr_tmp_result6181, 6 ; <i32> [#uses=1]
%ashr_tmp_result68 = lshr i32 59796, %rhs_masked67 ; <i32> [#uses=1]
%and_tmp_result70 = and i32 %ashr_tmp_result68, 3 ; <i32> [#uses=1]
%addconv82 = add i32 %addconv, %and_tmp_result70 ; <i32> [#uses=3]
%rangetmp = add i32 %addconv82, 536870912 ; <i32> [#uses=1]
%rangecmp = icmp ult i32 %rangetmp, 1073741824 ; <i1> [#uses=1]
br i1 %rangecmp, label %NumberLiteralIntFast, label %NumberLiteralIntSlow
NumberLiteralIntFast: ; preds = %no_exception7
%imm_shift = shl i32 %addconv82, 2 ; <i32> [#uses=1]
%imm_or = or i32 %imm_shift, 3 ; <i32> [#uses=1]
%imm_val = inttoptr i32 %imm_or to %Value ; <%Value> [#uses=1]
ret %Value %imm_val
NumberLiteralIntSlow: ; preds = %no_exception7
%toVal = call %Value @X4( i32 %addconv82 ) ; <%Value> [#uses=1]
ret %Value %toVal
}