[AArch64] Fix a build_vector pattern match fail
caused by defect in isBuildVectorAllZeros().
llvm-svn: 211567
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 5923f0e..522d7c5 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -148,33 +148,34 @@
if (N->getOpcode() != ISD::BUILD_VECTOR) return false;
- unsigned i = 0, e = N->getNumOperands();
-
- // Skip over all of the undef values.
- while (i != e && N->getOperand(i).getOpcode() == ISD::UNDEF)
- ++i;
+ bool IsAllUndef = true;
+ for (unsigned i = 0, e = N->getNumOperands(); i < e; ++i) {
+ if (N->getOperand(i).getOpcode() == ISD::UNDEF)
+ continue;
+ IsAllUndef = false;
+ // Do not accept build_vectors that aren't all constants or which have non-0
+ // elements. We have to be a bit careful here, as the type of the constant
+ // may not be the same as the type of the vector elements due to type
+ // legalization (the elements are promoted to a legal type for the target
+ // and a vector of a type may be legal when the base element type is not).
+ // We only want to check enough bits to cover the vector elements, because
+ // we care if the resultant vector is all zeros, not whether the individual
+ // constants are.
+ SDValue Zero = N->getOperand(i);
+ unsigned EltSize = N->getValueType(0).getVectorElementType().getSizeInBits();
+ if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Zero)) {
+ if (CN->getAPIntValue().countTrailingZeros() < EltSize)
+ return false;
+ } else if (ConstantFPSDNode *CFPN = dyn_cast<ConstantFPSDNode>(Zero)) {
+ if (CFPN->getValueAPF().bitcastToAPInt().countTrailingZeros() < EltSize)
+ return false;
+ } else
+ return false;
+ }
// Do not accept an all-undef vector.
- if (i == e) return false;
-
- // Do not accept build_vectors that aren't all constants or which have non-0
- // elements.
- SDValue Zero = N->getOperand(i);
- if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Zero)) {
- if (!CN->isNullValue())
- return false;
- } else if (ConstantFPSDNode *CFPN = dyn_cast<ConstantFPSDNode>(Zero)) {
- if (!CFPN->getValueAPF().isPosZero())
- return false;
- } else
+ if (IsAllUndef)
return false;
-
- // Okay, we have at least one 0 value, check to see if the rest match or are
- // undefs.
- for (++i; i != e; ++i)
- if (N->getOperand(i) != Zero &&
- N->getOperand(i).getOpcode() != ISD::UNDEF)
- return false;
return true;
}