[llvm-commits] [llvm] r143358 - /llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
Nadav Rotem
nadav.rotem at intel.com
Mon Oct 31 13:08:25 PDT 2011
Author: nadav
Date: Mon Oct 31 15:08:25 2011
New Revision: 143358
URL: http://llvm.org/viewvc/llvm-project?rev=143358&view=rev
Log:
Cleanup. Document. Make sure that this build_vector optimization only runs before the op legalizer and that the used type is legal.
Modified:
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=143358&r1=143357&r2=143358&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Mon Oct 31 15:08:25 2011
@@ -6941,9 +6941,9 @@
// Check to see if this is a BUILD_VECTOR of a bunch of values
// which come from any_extend or zero_extend nodes. If so, we can create
// a new BUILD_VECTOR using bit-casts which may enable other BUILD_VECTOR
- // optimizations.
+ // optimizations. We do not handle sign-extend because we can't fill the sign
+ // using shuffles.
EVT SourceType = MVT::Other;
- bool allExtend = true;
bool allAnyExt = true;
for (unsigned i = 0; i < NumInScalars; ++i) {
SDValue In = N->getOperand(i);
@@ -6953,9 +6953,9 @@
bool AnyExt = In.getOpcode() == ISD::ANY_EXTEND;
bool ZeroExt = In.getOpcode() == ISD::ZERO_EXTEND;
- // Abort non-extend incoming values.
+ // Abort if the element is not an extension.
if (!ZeroExt && !AnyExt) {
- allExtend = false;
+ SourceType = MVT::Other;
break;
}
@@ -6964,10 +6964,11 @@
// Check that all of the widened source types are the same.
if (SourceType == MVT::Other)
+ // First time.
SourceType = InTy;
else if (InTy != SourceType) {
// Multiple income types. Abort.
- allExtend = false;
+ SourceType = MVT::Other;
break;
}
@@ -6975,17 +6976,27 @@
allAnyExt &= AnyExt;
}
- // And we are post type-legalization,
- // If all of the values are Ext or undef,
- // We have a non undef entry.
- if (LegalTypes && allExtend && SourceType != MVT::Other) {
+
+ // In order to have valid types, all of the inputs must be extended from the
+ // same source type and all of the inputs must be any or zero extend.
+ // Scalar sizes must be a power of two.
+ EVT OutScalarTy = N->getValueType(0).getScalarType();
+ bool validTypes = SourceType != MVT::Other &&
+ isPowerOf2_32(OutScalarTy.getSizeInBits()) &&
+ isPowerOf2_32(SourceType.getSizeInBits());
+
+ // We perform this optimization post type-legalization because
+ // the type-legalizer often scalarizes integer-promoted vectors.
+ // Performing this optimization before may create bit-casts which
+ // will be type-legalized to complex code sequences.
+ // We perform this optimization only before the operation legalizer because we
+ // may introduce illegal operations.
+ if (LegalTypes && !LegalOperations && validTypes) {
bool isLE = TLI.isLittleEndian();
- EVT InScalarTy = SourceType.getScalarType();
- EVT OutScalarTy = N->getValueType(0).getScalarType();
- unsigned ElemRatio = OutScalarTy.getSizeInBits()/InScalarTy.getSizeInBits();
+ unsigned ElemRatio = OutScalarTy.getSizeInBits()/SourceType.getSizeInBits();
assert(ElemRatio > 1 && "Invalid element size ratio");
- SDValue Filler = allAnyExt ? DAG.getUNDEF(InScalarTy):
- DAG.getConstant(0, InScalarTy);
+ SDValue Filler = allAnyExt ? DAG.getUNDEF(SourceType):
+ DAG.getConstant(0, SourceType);
unsigned NewBVElems = ElemRatio * N->getValueType(0).getVectorNumElements();
SmallVector<SDValue, 8> Ops(NewBVElems, Filler);
@@ -6998,7 +7009,7 @@
Cast.getOpcode() == ISD::UNDEF) && "Invalid cast opcode");
SDValue In;
if (Cast.getOpcode() == ISD::UNDEF)
- In = DAG.getUNDEF(InScalarTy);
+ In = DAG.getUNDEF(SourceType);
else
In = Cast->getOperand(0);
unsigned Index = isLE ? (i * ElemRatio) :
@@ -7009,9 +7020,11 @@
}
// The type of the new BUILD_VECTOR node.
- EVT VecVT = EVT::getVectorVT(*DAG.getContext(), InScalarTy, NewBVElems);
+ EVT VecVT = EVT::getVectorVT(*DAG.getContext(), SourceType, NewBVElems);
assert(VecVT.getSizeInBits() == N->getValueType(0).getSizeInBits() &&
"Invalid vector size");
+ // Check if the new vector type is legal.
+ if (!isTypeLegal(VecVT)) return SDValue();
// Make the new BUILD_VECTOR.
SDValue BV = DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(),
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