Fold shifts with undef operands.
llvm-svn: 28167
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 60a749d..ca123f4 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -1439,11 +1439,14 @@
case ISD::FSUB:
case ISD::FDIV:
case ISD::FREM:
+ case ISD::SRA:
return N1; // fold op(undef, arg2) -> undef
case ISD::UDIV:
case ISD::SDIV:
case ISD::UREM:
case ISD::SREM:
+ case ISD::SRL:
+ case ISD::SHL:
return getConstant(0, VT); // fold op(undef, arg2) -> 0
}
}
@@ -1467,9 +1470,13 @@
return N2; // fold op(arg1, undef) -> undef
case ISD::MUL:
case ISD::AND:
+ case ISD::SRL:
+ case ISD::SHL:
return getConstant(0, VT); // fold op(arg1, undef) -> 0
case ISD::OR:
return getConstant(MVT::getIntVTBitMask(VT), VT);
+ case ISD::SRA:
+ return N1;
}
}