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Materialize global addresses via movt/movw pair, this is always better

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than doing the same via constpool:
1. Load from constpool costs 3 cycles on A9, movt/movw pair - just 2.
2. Load from constpool might stall up to 300 cycles due to cache miss.
3. Movt/movw does not use load/store unit.
4. Less constpool entries => better compiler performance.

This is only enabled on ELF systems, since darwin does not have needed
relocations (yet).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89720 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Anton Korobeynikov
2009-11-24 00:44:37 +00:00
parent 6935efcb66
commit 5cdc3a949a
11 changed files with 147 additions and 41 deletions
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20
lib/Target/ARM/ARMISelDAGToDAG.cpp
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@@ -261,7 +261,9 @@ bool ARMDAGToDAGISel::SelectAddrMode2(SDValue Op, SDValue N,
if (N.getOpcode() == ISD::FrameIndex) {
int FI = cast<FrameIndexSDNode>(N)->getIndex();
Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
} else if (N.getOpcode() == ARMISD::Wrapper) {
} else if (N.getOpcode() == ARMISD::Wrapper &&
!(Subtarget->useMovt() &&
N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
Base = N.getOperand(0);
}
Offset = CurDAG->getRegister(0, MVT::i32);
@@ -463,7 +465,9 @@ bool ARMDAGToDAGISel::SelectAddrMode5(SDValue Op, SDValue N,
if (N.getOpcode() == ISD::FrameIndex) {
int FI = cast<FrameIndexSDNode>(N)->getIndex();
Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
} else if (N.getOpcode() == ARMISD::Wrapper) {
} else if (N.getOpcode() == ARMISD::Wrapper &&
!(Subtarget->useMovt() &&
N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
Base = N.getOperand(0);
}
Offset = CurDAG->getTargetConstant(ARM_AM::getAM5Opc(ARM_AM::add, 0),
@@ -558,7 +562,13 @@ ARMDAGToDAGISel::SelectThumbAddrModeRI5(SDValue Op, SDValue N,
}
if (N.getOpcode() != ISD::ADD) {
Base = (N.getOpcode() == ARMISD::Wrapper) ? N.getOperand(0) : N;
if (N.getOpcode() == ARMISD::Wrapper &&
!(Subtarget->useMovt() &&
N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
Base = N.getOperand(0);
} else
Base = N;
Offset = CurDAG->getRegister(0, MVT::i32);
OffImm = CurDAG->getTargetConstant(0, MVT::i32);
return true;
@@ -681,7 +691,9 @@ bool ARMDAGToDAGISel::SelectT2AddrModeImm12(SDValue Op, SDValue N,
Base = CurDAG->getTargetFrameIndex(FI, TLI.getPointerTy());
OffImm = CurDAG->getTargetConstant(0, MVT::i32);
return true;
} else if (N.getOpcode() == ARMISD::Wrapper) {
} else if (N.getOpcode() == ARMISD::Wrapper &&
!(Subtarget->useMovt() &&
N.getOperand(0).getOpcode() == ISD::TargetGlobalAddress)) {
Base = N.getOperand(0);
if (Base.getOpcode() == ISD::TargetConstantPool)
return false; // We want to select t2LDRpci instead.