[PATCH] D15378: [X86] Determine if target shuffle contains zero elements
Simon Pilgrim via llvm-commits
llvm-commits at lists.llvm.org
Wed Jan 6 04:12:55 PST 2016
RKSimon updated this revision to Diff 44106.
RKSimon added a comment.
Updated now that the mask.empty() diffs have bveen committed in http://reviews.llvm.org/rL256921.
For tests, the PerformShuffleCombine tests continue to work as-is (they already supported SentinelZero as they deal with PSHUFB combines) - the other candidate is XFormVExtractWithShuffleIntoLoad and that will be able to be tested once I've added INSERTPS as a target shuffle in a future commit and enabled zero support.
Overall, this patch is more about preparing the ground instead of changing much functionality.
Repository:
rL LLVM
http://reviews.llvm.org/D15378
Files:
lib/Target/X86/X86ISelLowering.cpp
Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -4743,8 +4743,7 @@
/// uses one source. Note that this will set IsUnary for shuffles which use a
/// single input multiple times, and in those cases it will
/// adjust the mask to only have indices within that single input.
-/// FIXME: Add support for Decode*Mask functions that return SM_SentinelZero.
-static bool getTargetShuffleMask(SDNode *N, MVT VT,
+static bool getTargetShuffleMask(SDNode *N, MVT VT, bool AllowSentinelZero,
SmallVectorImpl<int> &Mask, bool &IsUnary) {
unsigned NumElems = VT.getVectorNumElements();
SDValue ImmN;
@@ -4870,10 +4869,7 @@
case X86ISD::VPERM2X128:
ImmN = N->getOperand(N->getNumOperands()-1);
DecodeVPERM2X128Mask(VT, cast<ConstantSDNode>(ImmN)->getZExtValue(), Mask);
- // Mask only contains negative index if an element is zero.
- if (std::any_of(Mask.begin(), Mask.end(),
- [](int M){ return M == SM_SentinelZero; }))
- return false;
+ IsUnary = IsFakeUnary = N->getOperand(0) == N->getOperand(1);
break;
case X86ISD::MOVSLDUP:
DecodeMOVSLDUPMask(VT, Mask);
@@ -5008,6 +5004,12 @@
if (Mask.empty())
return false;
+ // Check if we're getting a shuffle mask with zero'd elements.
+ if (!AllowSentinelZero)
+ if (std::any_of(Mask.begin(), Mask.end(),
+ [](int M){ return M == SM_SentinelZero; }))
+ return false;
+
// If we have a fake unary shuffle, the shuffle mask is spread across two
// inputs that are actually the same node. Re-map the mask to always point
// into the first input.
@@ -5046,19 +5048,19 @@
// Recurse into target specific vector shuffles to find scalars.
if (isTargetShuffle(Opcode)) {
MVT ShufVT = V.getSimpleValueType();
- unsigned NumElems = ShufVT.getVectorNumElements();
+ int NumElems = (int)ShufVT.getVectorNumElements();
SmallVector<int, 16> ShuffleMask;
bool IsUnary;
- if (!getTargetShuffleMask(N, ShufVT, ShuffleMask, IsUnary))
+ if (!getTargetShuffleMask(N, ShufVT, false, ShuffleMask, IsUnary))
return SDValue();
int Elt = ShuffleMask[Index];
- if (Elt < 0)
+ if (Elt == SM_SentinelUndef)
return DAG.getUNDEF(ShufVT.getVectorElementType());
- SDValue NewV = (Elt < (int)NumElems) ? N->getOperand(0)
- : N->getOperand(1);
+ assert(0 <= Elt && Elt < (2*NumElems) && "Shuffle index out of range");
+ SDValue NewV = (Elt < NumElems) ? N->getOperand(0) : N->getOperand(1);
return getShuffleScalarElt(NewV.getNode(), Elt % NumElems, DAG,
Depth+1);
}
@@ -23184,7 +23186,7 @@
return false;
SmallVector<int, 16> OpMask;
bool IsUnary;
- bool HaveMask = getTargetShuffleMask(Op.getNode(), VT, OpMask, IsUnary);
+ bool HaveMask = getTargetShuffleMask(Op.getNode(), VT, true, OpMask, IsUnary);
// We only can combine unary shuffles which we can decode the mask for.
if (!HaveMask || !IsUnary)
return false;
@@ -23281,7 +23283,7 @@
MVT VT = N.getSimpleValueType();
SmallVector<int, 4> Mask;
bool IsUnary;
- bool HaveMask = getTargetShuffleMask(N.getNode(), VT, Mask, IsUnary);
+ bool HaveMask = getTargetShuffleMask(N.getNode(), VT, false, Mask, IsUnary);
(void)HaveMask;
assert(HaveMask);
@@ -23883,13 +23885,13 @@
SmallVector<int, 16> ShuffleMask;
bool UnaryShuffle;
if (!getTargetShuffleMask(InVec.getNode(), CurrentVT.getSimpleVT(),
- ShuffleMask, UnaryShuffle))
+ false, ShuffleMask, UnaryShuffle))
return SDValue();
// Select the input vector, guarding against out of range extract vector.
unsigned NumElems = CurrentVT.getVectorNumElements();
int Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
- int Idx = (Elt > (int)NumElems) ? -1 : ShuffleMask[Elt];
+ int Idx = (Elt > (int)NumElems) ? SM_SentinelUndef : ShuffleMask[Elt];
SDValue LdNode = (Idx < (int)NumElems) ? InVec.getOperand(0)
: InVec.getOperand(1);
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