remove cases handled elsewhere
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@28150 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 16ce87a..3f9b774 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1938,30 +1938,16 @@
return DAG.getNode(ISD::SIGN_EXTEND, VT, Truncate);
}
- // If the input is already sign extended, just drop the extend.
+ // If the input is already sign extended, just drop the extension.
if (TLI.ComputeNumSignBits(N0) >= MVT::getSizeInBits(VT)-EVTBits+1)
return N0;
- // fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt1
- if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
- cast<VTSDNode>(N0.getOperand(1))->getVT() <= EVT) {
- return N0;
- }
// fold (sext_in_reg (sext_in_reg x, VT2), VT1) -> (sext_in_reg x, minVT) pt2
if (N0.getOpcode() == ISD::SIGN_EXTEND_INREG &&
EVT < cast<VTSDNode>(N0.getOperand(1))->getVT()) {
return DAG.getNode(ISD::SIGN_EXTEND_INREG, VT, N0.getOperand(0), N1);
}
- // fold (sext_in_reg (sextload x)) -> (sextload x)
- if (N0.getOpcode() == ISD::SEXTLOAD &&
- cast<VTSDNode>(N0.getOperand(3))->getVT() <= EVT) {
- return N0;
- }
- // fold (sext_in_reg (setcc x)) -> setcc x iff (setcc x) == 0 or -1
- if (N0.getOpcode() == ISD::SETCC &&
- TLI.getSetCCResultContents() ==
- TargetLowering::ZeroOrNegativeOneSetCCResult)
- return N0;
+
// fold (sext_in_reg x) -> (zext_in_reg x) if the sign bit is zero
if (TLI.MaskedValueIsZero(N0, 1ULL << (EVTBits-1)))
return DAG.getZeroExtendInReg(N0, EVT);