[PowerPC] Enable splat generation for BUILD_VECTOR with little endian
When enabling PPC64LE, I disabled some optimizations of BUILD_VECTOR
nodes for little endian because wrong results were produced. I've
subsequently investigated and found this is due to a call to
BuildVectorSDNode::isConstantSplat that was always specifying
big-endian. With this changed to correctly identify the target
endianness, the optimizations work as expected.
I found another case of a call to the same method with big-endian
hardcoded, in PPC::isAllNegativeZeroVector(). I discovered this was
an orphaned method with no callers, so I've just removed it.
The existing test/CodeGen/PowerPC/vec_constants.ll checks these
optimizations, so for testing I've just added a variant for little
endian.
llvm-svn: 234011
diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 1c2659c..7e2e9b3 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -1287,22 +1287,6 @@
return true;
}
-/// isAllNegativeZeroVector - Returns true if all elements of build_vector
-/// are -0.0.
-bool PPC::isAllNegativeZeroVector(SDNode *N) {
- BuildVectorSDNode *BV = cast<BuildVectorSDNode>(N);
-
- APInt APVal, APUndef;
- unsigned BitSize;
- bool HasAnyUndefs;
-
- if (BV->isConstantSplat(APVal, APUndef, BitSize, HasAnyUndefs, 32, true))
- if (ConstantFPSDNode *CFP = dyn_cast<ConstantFPSDNode>(N->getOperand(0)))
- return CFP->getValueAPF().isNegZero();
-
- return false;
-}
-
/// getVSPLTImmediate - Return the appropriate VSPLT* immediate to splat the
/// specified isSplatShuffleMask VECTOR_SHUFFLE mask.
unsigned PPC::getVSPLTImmediate(SDNode *N, unsigned EltSize,
@@ -6609,7 +6593,8 @@
unsigned SplatBitSize;
bool HasAnyUndefs;
if (! BVN->isConstantSplat(APSplatBits, APSplatUndef, SplatBitSize,
- HasAnyUndefs, 0, true) || SplatBitSize > 32)
+ HasAnyUndefs, 0, !Subtarget.isLittleEndian()) ||
+ SplatBitSize > 32)
return SDValue();
unsigned SplatBits = APSplatBits.getZExtValue();
@@ -6676,22 +6661,6 @@
return DAG.getNode(ISD::BITCAST, dl, Op.getValueType(), Res);
}
- // The remaining cases assume either big endian element order or
- // a splat-size that equates to the element size of the vector
- // to be built. An example that doesn't work for little endian is
- // {0, -1, 0, -1, 0, -1, 0, -1} which has a splat size of 32 bits
- // and a vector element size of 16 bits. The code below will
- // produce the vector in big endian element order, which for little
- // endian is {-1, 0, -1, 0, -1, 0, -1, 0}.
-
- // For now, just avoid these optimizations in that case.
- // FIXME: Develop correct optimizations for LE with mismatched
- // splat and element sizes.
-
- if (Subtarget.isLittleEndian() &&
- SplatSize != Op.getValueType().getVectorElementType().getSizeInBits())
- return SDValue();
-
// Check to see if this is a wide variety of vsplti*, binop self cases.
static const signed char SplatCsts[] = {
-1, 1, -2, 2, -3, 3, -4, 4, -5, 5, -6, 6, -7, 7,