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Implement code to keep the stack pointer aligned to an 8 byte boundary.
This improves the performance of the power benchmark by a few percent. This will be neccesary for SSE code, which requires 16 byte alignment of the stack. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5320 91177308-0d34-0410-b5e6-96231b3b80d8
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@ -386,7 +386,7 @@ void ISel::LoadArgumentsToVirtualRegs(Function &Fn) {
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// [ESP + 8] -- second argument, if first argument is four bytes in size
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// ...
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//
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unsigned ArgOffset = 4;
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unsigned ArgOffset = 0; // Frame mechanisms handle retaddr slot
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MachineFrameInfo *MFI = F->getFrameInfo();
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for (Function::aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {
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@ -386,7 +386,7 @@ void ISel::LoadArgumentsToVirtualRegs(Function &Fn) {
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// [ESP + 8] -- second argument, if first argument is four bytes in size
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// ...
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//
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unsigned ArgOffset = 4;
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unsigned ArgOffset = 0; // Frame mechanisms handle retaddr slot
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MachineFrameInfo *MFI = F->getFrameInfo();
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for (Function::aiterator I = Fn.abegin(), E = Fn.aend(); I != E; ++I) {
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@ -13,6 +13,8 @@
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#include "llvm/CodeGen/MachineInstrBuilder.h"
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#include "llvm/CodeGen/MachineFunction.h"
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#include "llvm/CodeGen/MachineFrameInfo.h"
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#include "llvm/Target/TargetMachine.h"
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#include "llvm/Target/TargetFrameInfo.h"
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#include "Support/CommandLine.h"
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namespace {
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@ -105,6 +107,12 @@ void X86RegisterInfo::eliminateCallFramePseudoInstr(MachineFunction &MF,
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// <amt>'
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unsigned Amount = Old->getOperand(0).getImmedValue();
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if (Amount != 0) {
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// We need to keep the stack aligned properly. To do this, we round the
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// amount of space needed for the outgoing arguments up to the next
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// alignment boundary.
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unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment();
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Amount = (Amount+Align-1)/Align*Align;
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if (Old->getOpcode() == X86::ADJCALLSTACKDOWN) {
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New=BuildMI(X86::SUBri32, 2, X86::ESP).addReg(X86::ESP).addZImm(Amount);
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} else {
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@ -191,6 +199,11 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const {
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//
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NumBytes += MFI->getMaxCallFrameSize();
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// Round the size to a multiple of the alignment (don't forget the 4 byte
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// offset though).
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unsigned Align = MF.getTarget().getFrameInfo().getStackAlignment();
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NumBytes = ((NumBytes+4)+Align-1)/Align*Align - 4;
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// Update frame info to pretend that this is part of the stack...
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MFI->setStackSize(NumBytes);
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}
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@ -37,7 +37,7 @@ X86TargetMachine::X86TargetMachine(unsigned Config)
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1, 4,
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(Config & TM::PtrSizeMask) == TM::PtrSize64 ? 8 : 4,
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(Config & TM::PtrSizeMask) == TM::PtrSize64 ? 8 : 4),
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FrameInfo(TargetFrameInfo::StackGrowsDown, 1/*16*/, 0) {
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FrameInfo(TargetFrameInfo::StackGrowsDown, 8/*16 for SSE*/, 4) {
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}
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/// addPassesToJITCompile - Add passes to the specified pass manager to
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