For values that are live across basic blocks and need promotion, use ANY_EXTEND

instead of ZERO_EXTEND to eliminate extraneous extensions.  This eliminates
dead zero extensions on formal arguments and other cases on PPC, implementing
the newly tightened up test/Regression/CodeGen/PowerPC/small-arguments.ll test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23205 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-09-02 00:19:37 +00:00
parent 13c78e2e5f
commit fab08875b7

View File

@ -491,7 +491,7 @@ void SelectionDAGLowering::visitBinary(User &I, unsigned Opcode, bool isShift) {
SDOperand Op2 = getValue(I.getOperand(1));
if (isShift)
Op2 = DAG.getNode(ISD::ZERO_EXTEND, TLI.getShiftAmountTy(), Op2);
Op2 = DAG.getNode(ISD::ANY_EXTEND, TLI.getShiftAmountTy(), Op2);
setValue(&I, DAG.getNode(Opcode, Op1.getValueType(), Op1, Op2));
}
@ -1025,7 +1025,7 @@ CopyValueToVirtualRegister(SelectionDAGLowering &SDL, Value *V, unsigned Reg) {
if (MVT::isFloatingPoint(SrcVT))
Op = DAG.getNode(ISD::FP_EXTEND, DestVT, Op);
else
Op = DAG.getNode(ISD::ZERO_EXTEND, DestVT, Op);
Op = DAG.getNode(ISD::ANY_EXTEND, DestVT, Op);
return DAG.getCopyToReg(SDL.getRoot(), Reg, Op);
} else {
// The src value is expanded into multiple registers.
@ -1078,14 +1078,9 @@ LowerArguments(BasicBlock *BB, SelectionDAGLowering &SDL,
if (!AI->use_empty()) {
SDL.setValue(AI, Args[a]);
if (0 && IsOnlyUsedInOneBasicBlock(AI) == F.begin()) {
// Only used in the entry block, no need to copy it to a vreg for
// other blocks.
} else {
SDOperand Copy =
CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]);
UnorderedChains.push_back(Copy);
}
SDOperand Copy =
CopyValueToVirtualRegister(SDL, AI, FuncInfo.ValueMap[AI]);
UnorderedChains.push_back(Copy);
}
} else {
// Otherwise, if any argument is only accessed in a single basic block,