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Fix memcpy lowering when addresses are 4-byte aligned but size is not multiple of 4. 

llvm-svn: 43234
This commit is contained in:
Evan Cheng 2007-10-22 22:11:27 +00:00
parent 6eafb030f0
commit 1f2dd35898
4 changed files with 101 additions and 40 deletions
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117
llvm/lib/Target/ARM/ARMISelLowering.cpp
View File

@ -1287,7 +1287,8 @@ static SDOperand LowerSRx(SDOperand Op, SelectionDAG &DAG,
return DAG.getNode(ISD::BUILD_PAIR, MVT::i64, Lo, Hi);
}
SDOperand ARMTargetLowering::LowerMEMCPY(SDOperand Op, SelectionDAG &DAG) {
SDOperand ARMTargetLowering::LowerMEMCPY(SDOperand Op, SelectionDAG &DAG,
const ARMSubtarget *ST) {
SDOperand ChainOp = Op.getOperand(0);
SDOperand DestOp = Op.getOperand(1);
SDOperand SourceOp = Op.getOperand(2);
@ -1305,25 +1306,18 @@ SDOperand ARMTargetLowering::LowerMEMCPY(SDOperand Op, SelectionDAG &DAG) {
assert(!AlwaysInline && "Cannot inline copy of unknown size");
return LowerMEMCPYCall(ChainOp, DestOp, SourceOp, CountOp, DAG);
}
unsigned Size = I->getValue();
if (AlwaysInline)
return LowerMEMCPYInline(ChainOp, DestOp, SourceOp, Size, Align, DAG);
// The libc version is likely to be faster for the following cases. It can
// If not DWORD aligned or if size is more than threshold, then call memcpy.
// The libc version is likely to be faster for the these cases. It can
// use the address value and run time information about the CPU.
// With glibc 2.6.1 on a core 2, coping an array of 100M longs was 30% faster
// If not DWORD aligned, call memcpy.
if ((Align & 3) != 0)
return LowerMEMCPYCall(ChainOp, DestOp, SourceOp, CountOp, DAG);
// If size is more than the threshold, call memcpy.
// if (Size > Subtarget->getMinRepStrSizeThreshold())
if (Size >= 64)
return LowerMEMCPYCall(ChainOp, DestOp, SourceOp, CountOp, DAG);
return LowerMEMCPYInline(ChainOp, DestOp, SourceOp, Size, Align, DAG);
// FIXME: For now, we don't lower memcpy's to loads / stores for Thumb. Change
// this once Thumb ldmia / stmia support is added.
unsigned Size = I->getValue();
if (AlwaysInline ||
(!ST->isThumb() && Size < 64 && (Align & 3) == 0))
return LowerMEMCPYInline(ChainOp, DestOp, SourceOp, Size, Align, DAG);
return LowerMEMCPYCall(ChainOp, DestOp, SourceOp, CountOp, DAG);
}
SDOperand ARMTargetLowering::LowerMEMCPYCall(SDOperand Chain,
@ -1350,46 +1344,93 @@ SDOperand ARMTargetLowering::LowerMEMCPYInline(SDOperand Chain,
unsigned Size,
unsigned Align,
SelectionDAG &DAG) {
// Do repeated 4-byte loads and stores. To be improved.
assert((Size& 3) == 0);
assert((Align & 3) == 0);
// Do repeated 4-byte loads and stores. To be improved.
assert((Align & 3) == 0 && "Expected 4-byte aligned addresses!");
unsigned BytesLeft = Size & 3;
unsigned NumMemOps = Size >> 2;
unsigned EmittedNumMemOps = 0;
unsigned SrcOff = 0, DstOff = 0;
MVT::ValueType VT = MVT::i32;
unsigned VTSize = 4;
unsigned i = 0;
const unsigned MAX_LOADS_IN_LDM = 6;
SDOperand LoadChains[MAX_LOADS_IN_LDM];
SDOperand TFOps[MAX_LOADS_IN_LDM];
SDOperand Loads[MAX_LOADS_IN_LDM];
// Emit up to 4 loads, then a TokenFactor barrier, then the same
// number of stores. The loads and stores will get combined into
// Emit up to MAX_LOADS_IN_LDM loads, then a TokenFactor barrier, then the
// same number of stores. The loads and stores will get combined into
// ldm/stm later on.
while(EmittedNumMemOps < NumMemOps) {
unsigned i;
for (i=0; i<MAX_LOADS_IN_LDM && EmittedNumMemOps+i < NumMemOps; i++) {
while (EmittedNumMemOps < NumMemOps) {
for (i = 0;
i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
Loads[i] = DAG.getLoad(VT, Chain,
DAG.getNode(ISD::ADD, VT, Source,
DAG.getConstant(SrcOff, VT)),
DAG.getNode(ISD::ADD, MVT::i32, Source,
DAG.getConstant(SrcOff, MVT::i32)),
NULL, 0);
LoadChains[i] = Loads[i].getValue(1);
TFOps[i] = Loads[i].getValue(1);
SrcOff += VTSize;
}
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, &TFOps[0], i);
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, &LoadChains[0], i);
for (i=0; i<MAX_LOADS_IN_LDM && EmittedNumMemOps+i < NumMemOps; i++) {
Chain = DAG.getStore(Chain, Loads[i],
DAG.getNode(ISD::ADD, VT, Dest,
DAG.getConstant(DstOff, VT)),
for (i = 0;
i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
TFOps[i] = DAG.getStore(Chain, Loads[i],
DAG.getNode(ISD::ADD, MVT::i32, Dest,
DAG.getConstant(DstOff, MVT::i32)),
NULL, 0);
DstOff += VTSize;
}
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, &TFOps[0], i);
EmittedNumMemOps += i;
}
return Chain;
if (BytesLeft == 0)
return Chain;
// Issue loads / stores for the trailing (1 - 3) bytes.
unsigned BytesLeftSave = BytesLeft;
i = 0;
while (BytesLeft) {
if (BytesLeft >= 2) {
VT = MVT::i16;
VTSize = 2;
} else {
VT = MVT::i8;
VTSize = 1;
}
Loads[i] = DAG.getLoad(VT, Chain,
DAG.getNode(ISD::ADD, MVT::i32, Source,
DAG.getConstant(SrcOff, MVT::i32)),
NULL, 0);
TFOps[i] = Loads[i].getValue(1);
++i;
SrcOff += VTSize;
BytesLeft -= VTSize;
}
Chain = DAG.getNode(ISD::TokenFactor, MVT::Other, &TFOps[0], i);
i = 0;
BytesLeft = BytesLeftSave;
while (BytesLeft) {
if (BytesLeft >= 2) {
VT = MVT::i16;
VTSize = 2;
} else {
VT = MVT::i8;
VTSize = 1;
}
TFOps[i] = DAG.getStore(Chain, Loads[i],
DAG.getNode(ISD::ADD, MVT::i32, Dest,
DAG.getConstant(DstOff, MVT::i32)),
NULL, 0);
++i;
DstOff += VTSize;
BytesLeft -= VTSize;
}
return DAG.getNode(ISD::TokenFactor, MVT::Other, &TFOps[0], i);
}
SDOperand ARMTargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
@ -1419,7 +1460,7 @@ SDOperand ARMTargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
case ISD::RETURNADDR: break;
case ISD::FRAMEADDR: break;
case ISD::GLOBAL_OFFSET_TABLE: return LowerGLOBAL_OFFSET_TABLE(Op, DAG);
case ISD::MEMCPY: return LowerMEMCPY(Op, DAG);
case ISD::MEMCPY: return LowerMEMCPY(Op, DAG, Subtarget);
}
return SDOperand();
}

5
llvm/lib/Target/ARM/ARMISelLowering.h
View File

@ -130,11 +130,12 @@ namespace llvm {
SDOperand LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
SelectionDAG &DAG);
SDOperand LowerToTLSExecModels(GlobalAddressSDNode *GA,
SelectionDAG &DAG);
SelectionDAG &DAG);
SDOperand LowerGLOBAL_OFFSET_TABLE(SDOperand Op, SelectionDAG &DAG);
SDOperand LowerFORMAL_ARGUMENTS(SDOperand Op, SelectionDAG &DAG);
SDOperand LowerBR_JT(SDOperand Op, SelectionDAG &DAG);
SDOperand LowerMEMCPY(SDOperand Op, SelectionDAG &DAG);
SDOperand LowerMEMCPY(SDOperand Op, SelectionDAG &DAG,
const ARMSubtarget *ST);
SDOperand LowerMEMCPYCall(SDOperand Chain, SDOperand Dest,
SDOperand Source, SDOperand Count,
SelectionDAG &DAG);

4
llvm/lib/Target/ARM/README-Thumb.txt
View File

@ -221,3 +221,7 @@ LPC0:
Make register allocator / spiller smarter so we can re-materialize "mov r, imm",
etc. Almost all Thumb instructions clobber condition code.
//===---------------------------------------------------------------------===//
Add ldmia, stmia support.

15
llvm/test/CodeGen/ARM/memcpy-inline.ll Normal file
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@ -0,0 +1,15 @@
; RUN: llvm-as < %s | llc -mtriple=arm-apple-darwin | grep ldmia
; RUN: llvm-as < %s | llc -mtriple=arm-apple-darwin | grep ldrb
; RUN: llvm-as < %s | llc -mtriple=arm-apple-darwin | grep ldrh
%struct.x = type { i8, i8, i8, i8, i8, i8, i8, i8, i8, i8, i8 }
@src = external global %struct.x
@dst = external global %struct.x
define i32 @t() {
entry:
call void @llvm.memcpy.i32( i8* getelementptr (%struct.x* @dst, i32 0, i32 0), i8* getelementptr (%struct.x* @src, i32 0, i32 0), i32 11, i32 8 )
ret i32 0
}
declare void @llvm.memcpy.i32(i8*, i8*, i32, i32)