AVX-512: Fixed a bug in emitting compare for MVT:i1 type.
Added a test.
llvm-svn: 215889
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 1f5f44c..951c1a2 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -2544,12 +2544,30 @@
SDValue N0 = Node->getOperand(0);
SDValue N1 = Node->getOperand(1);
+ if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() &&
+ HasNoSignedComparisonUses(Node)) {
+ // Look for (X86cmp (truncate $op, i1), 0) and try to convert to a
+ // smaller encoding
+ if (Opcode == X86ISD::CMP && N0.getValueType() == MVT::i1 &&
+ X86::isZeroNode(N1)) {
+ SDValue Reg = N0.getOperand(0);
+ SDValue Imm = CurDAG->getTargetConstant(1, MVT::i8);
+
+ // Emit testb
+ if (Reg.getScalarValueSizeInBits() > 8)
+ Reg = CurDAG->getTargetExtractSubreg(X86::sub_8bit, dl, MVT::i8, Reg);
+ // Emit a testb.
+ SDNode *NewNode = CurDAG->getMachineNode(X86::TEST8ri, dl, MVT::i32,
+ Reg, Imm);
+ ReplaceUses(SDValue(Node, 0), SDValue(NewNode, 0));
+ return nullptr;
+ }
+
+ N0 = N0.getOperand(0);
+ }
// Look for (X86cmp (and $op, $imm), 0) and see if we can convert it to
// use a smaller encoding.
- if (N0.getOpcode() == ISD::TRUNCATE && N0.hasOneUse() &&
- HasNoSignedComparisonUses(Node))
- // Look past the truncate if CMP is the only use of it.
- N0 = N0.getOperand(0);
+ // Look past the truncate if CMP is the only use of it.
if ((N0.getNode()->getOpcode() == ISD::AND ||
(N0.getResNo() == 0 && N0.getNode()->getOpcode() == X86ISD::AND)) &&
N0.getNode()->hasOneUse() &&