- Teach SelectionDAG::isKnownNeverZero to return true (op x, c) when c is
non-zero.
- Teach X86 cmov optimization to eliminate the cmov from ctlz, cttz extension
when the source of X86ISD::BSR / X86ISD::BSF is proven to be non-zero.
rdar://9490949
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131948 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index dd33205..d331ee2 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2050,14 +2050,15 @@
break;
default:
- // Allow the target to implement this method for its nodes.
- if (Op.getOpcode() >= ISD::BUILTIN_OP_END) {
+ if (Op.getOpcode() < ISD::BUILTIN_OP_END)
+ break;
+ // Fallthrough
case ISD::INTRINSIC_WO_CHAIN:
case ISD::INTRINSIC_W_CHAIN:
case ISD::INTRINSIC_VOID:
- TLI.computeMaskedBitsForTargetNode(Op, Mask, KnownZero, KnownOne, *this,
- Depth);
- }
+ // Allow the target to implement this method for its nodes.
+ TLI.computeMaskedBitsForTargetNode(Op, Mask, KnownZero, KnownOne, *this,
+ Depth);
return;
}
}
@@ -2322,6 +2323,13 @@
return !C->isZero();
// TODO: Recognize more cases here.
+ switch (Op.getOpcode()) {
+ default: break;
+ case ISD::OR:
+ if (const ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1)))
+ return !C->isNullValue();
+ break;
+ }
return false;
}