add support for dynamic_stackalloc to the dag isel (thanks andrew ;)

next up: support argument passing in memory, not just registers


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24490 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Duraid Madina 2005-11-25 07:49:25 +00:00
parent e4f17a5f9b
commit 7b1e154c5a

View File

@ -536,9 +536,37 @@ SDOperand IA64DAGToDAGISel::Select(SDOperand Op) {
case ISD::SREM:
case ISD::UREM: return SelectDIV(Op);
/* todo:
* case ISD::DYNAMIC_STACKALLOC:
*/
case ISD::DYNAMIC_STACKALLOC: {
if (!isa<ConstantSDNode>(N->getOperand(2)) ||
cast<ConstantSDNode>(N->getOperand(2))->getValue() != 0) {
std::cerr << "Cannot allocate stack object with greater alignment than"
<< " the stack alignment yet!";
abort();
}
SDOperand Chain = Select(N->getOperand(0));
SDOperand Amt = Select(N->getOperand(1));
SDOperand Reg = CurDAG->getRegister(IA64::r12, MVT::i64);
SDOperand Val = CurDAG->getCopyFromReg(Chain, IA64::r12, MVT::i64);
Chain = Val.getValue(1);
// Subtract the amount (guaranteed to be a multiple of the stack alignment)
// from the stack pointer, giving us the result pointer.
SDOperand Result = Select(CurDAG->getNode(ISD::SUB, MVT::i64, Val, Amt));
// Copy this result back into r12.
Chain = CurDAG->getNode(ISD::CopyToReg, MVT::Other, Chain, Reg, Result);
// Copy this result back out of r12 to make sure we're not using the stack
// space without decrementing the stack pointer.
Result = CurDAG->getCopyFromReg(Chain, IA64::r12, MVT::i64);
// Finally, replace the DYNAMIC_STACKALLOC with the copyfromreg.
CodeGenMap[Op.getValue(0)] = Result;
CodeGenMap[Op.getValue(1)] = Result.getValue(1);
return SDOperand(Result.Val, Op.ResNo);
}
case ISD::ConstantFP: {
SDOperand Chain = CurDAG->getEntryNode(); // this is a constant, so..