Lower a build_vector with all constants into a constpool load unless it can be done with a move to low part.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@44921 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 3ca9f56..8375141 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -3157,21 +3157,21 @@
unsigned NumZero = 0;
unsigned NumNonZero = 0;
unsigned NonZeros = 0;
- unsigned NumNonZeroImms = 0;
+ bool HasNonImms = false;
SmallSet<SDOperand, 8> Values;
for (unsigned i = 0; i < NumElems; ++i) {
SDOperand Elt = Op.getOperand(i);
- if (Elt.getOpcode() != ISD::UNDEF) {
- Values.insert(Elt);
- if (isZeroNode(Elt))
- NumZero++;
- else {
- NonZeros |= (1 << i);
- NumNonZero++;
- if (Elt.getOpcode() == ISD::Constant ||
- Elt.getOpcode() == ISD::ConstantFP)
- NumNonZeroImms++;
- }
+ if (Elt.getOpcode() == ISD::UNDEF)
+ continue;
+ Values.insert(Elt);
+ if (Elt.getOpcode() != ISD::Constant &&
+ Elt.getOpcode() != ISD::ConstantFP)
+ HasNonImms = true;
+ if (isZeroNode(Elt))
+ NumZero++;
+ else {
+ NonZeros |= (1 << i);
+ NumNonZero++;
}
}
@@ -3185,7 +3185,7 @@
return SDOperand();
// Special case for single non-zero element.
- if (NumNonZero == 1) {
+ if (NumNonZero == 1 && NumElems <= 4) {
unsigned Idx = CountTrailingZeros_32(NonZeros);
SDOperand Item = Op.getOperand(Idx);
Item = DAG.getNode(ISD::SCALAR_TO_VECTOR, VT, Item);
@@ -3193,6 +3193,8 @@
// Turn it into a MOVL (i.e. movss, movsd, or movd) to a zero vector.
return getShuffleVectorZeroOrUndef(Item, VT, NumElems, Idx,
NumZero > 0, DAG);
+ else if (!HasNonImms) // Otherwise, it's better to do a constpool load.
+ return SDOperand();
if (EVTBits == 32) {
// Turn it into a shuffle of zero and zero-extended scalar to vector.
@@ -3212,7 +3214,7 @@
// A vector full of immediates; various special cases are already
// handled, so this is best done with a single constant-pool load.
- if (NumNonZero == NumNonZeroImms)
+ if (!HasNonImms)
return SDOperand();
// Let legalizer expand 2-wide build_vectors.