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Convert feature of the simple isel over for the pattern isel to use.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21840 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-05-10 03:53:18 +00:00
parent 641f02f10f
commit 6415bb4c29
1 changed files with 28 additions and 5 deletions
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33
lib/Target/X86/X86ISelPattern.cpp
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@ -120,11 +120,13 @@ namespace {
};
}
std::vector<SDOperand>
X86TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
std::vector<SDOperand> ArgValues;
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
// Add DAG nodes to load the arguments... On entry to a function on the X86,
// the stack frame looks like this:
//
@ -133,9 +135,6 @@ X86TargetLowering::LowerArguments(Function &F, SelectionDAG &DAG) {
// [ESP + 8] -- second argument, if first argument is four bytes in size
// ...
//
MachineFunction &MF = DAG.getMachineFunction();
MachineFrameInfo *MFI = MF.getFrameInfo();
unsigned ArgOffset = 0; // Frame mechanisms handle retaddr slot
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I) {
MVT::ValueType ObjectVT = getValueType(I->getType());
@ -433,17 +432,34 @@ namespace {
};
}
/// EmitSpecialCodeForMain - Emit any code that needs to be executed only in
/// the main function.
static void EmitSpecialCodeForMain(MachineBasicBlock *BB,
MachineFrameInfo *MFI) {
// Switch the FPU to 64-bit precision mode for better compatibility and speed.
int CWFrameIdx = MFI->CreateStackObject(2, 2);
addFrameReference(BuildMI(BB, X86::FNSTCW16m, 4), CWFrameIdx);
// Set the high part to be 64-bit precision.
addFrameReference(BuildMI(BB, X86::MOV8mi, 5),
CWFrameIdx, 1).addImm(2);
// Reload the modified control word now.
addFrameReference(BuildMI(BB, X86::FLDCW16m, 4), CWFrameIdx);
}
/// InstructionSelectBasicBlock - This callback is invoked by SelectionDAGISel
/// when it has created a SelectionDAG for us to codegen.
void ISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
// While we're doing this, keep track of whether we see any FP code for
// FP_REG_KILL insertion.
ContainsFPCode = false;
MachineFunction *MF = BB->getParent();
// Scan the PHI nodes that already are inserted into this basic block. If any
// of them is a PHI of a floating point value, we need to insert an
// FP_REG_KILL.
SSARegMap *RegMap = BB->getParent()->getSSARegMap();
SSARegMap *RegMap = MF->getSSARegMap();
for (MachineBasicBlock::iterator I = BB->begin(), E = BB->end();
I != E; ++I) {
assert(I->getOpcode() == X86::PHI &&
@ -455,6 +471,13 @@ void ISel::InstructionSelectBasicBlock(SelectionDAG &DAG) {
}
}
// If this is the entry block of main, emit special code for main.
if (BB == MF->begin()) {
const Function *F = MF->getFunction();
if (F->hasExternalLinkage() && F->getName() == "main")
EmitSpecialCodeForMain(BB, MF->getFrameInfo());
}
// Compute the RegPressureMap, which is an approximation for the number of
// registers required to compute each node.
ComputeRegPressure(DAG.getRoot());