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SelectionDAG: Optimize expansion of vec_type = BITCAST scalar_type

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The legalizer can now do this type of expansion for more
type combinations without loading and storing to and
from the stack.

NOTE: This is a candidate for the 3.4 branch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195398 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Tom Stellard 2013-11-22 00:41:05 +00:00
parent b7bad852f4
commit 0ffcaa0d54
3 changed files with 57 additions and 11 deletions
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6
lib/CodeGen/SelectionDAG/LegalizeTypes.h
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@ -731,6 +731,12 @@ private:
GetExpandedFloat(Op, Lo, Hi); GetExpandedFloat(Op, Lo, Hi);
} }
/// This function will split the integer \p Op into \p NumElements
/// operations of type \p EltVT and store them in \p Ops.
void IntegerToVector(SDValue Op, unsigned NumElements,
SmallVectorImpl<SDValue> &Ops, EVT EltVT);
// Generic Result Expansion. // Generic Result Expansion.
void ExpandRes_MERGE_VALUES (SDNode *N, unsigned ResNo, void ExpandRes_MERGE_VALUES (SDNode *N, unsigned ResNo,
SDValue &Lo, SDValue &Hi); SDValue &Lo, SDValue &Hi);

47
lib/CodeGen/SelectionDAG/LegalizeTypesGeneric.cpp
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@ -306,6 +306,25 @@ void DAGTypeLegalizer::ExpandRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
// Generic Operand Expansion. // Generic Operand Expansion.
//===--------------------------------------------------------------------===// //===--------------------------------------------------------------------===//
void DAGTypeLegalizer::IntegerToVector(SDValue Op, unsigned NumElements,
SmallVectorImpl<SDValue> &Ops,
EVT EltVT) {
assert(Op.getValueType().isInteger());
SDLoc DL(Op);
SDValue Parts[2];
if (NumElements > 1) {
NumElements >>= 1;
SplitInteger(Op, Parts[0], Parts[1]);
if (TLI.isBigEndian())
std::swap(Parts[0], Parts[1]);
IntegerToVector(Parts[0], NumElements, Ops, EltVT);
IntegerToVector(Parts[1], NumElements, Ops, EltVT);
} else {
Ops.push_back(DAG.getNode(ISD::BITCAST, DL, EltVT, Op));
}
}
SDValue DAGTypeLegalizer::ExpandOp_BITCAST(SDNode *N) { SDValue DAGTypeLegalizer::ExpandOp_BITCAST(SDNode *N) {
SDLoc dl(N); SDLoc dl(N);
if (N->getValueType(0).isVector()) { if (N->getValueType(0).isVector()) {
@ -314,21 +333,27 @@ SDValue DAGTypeLegalizer::ExpandOp_BITCAST(SDNode *N) {
// instead, but only if the new vector type is legal (otherwise there // instead, but only if the new vector type is legal (otherwise there
// is no point, and it might create expansion loops). For example, on // is no point, and it might create expansion loops). For example, on
// x86 this turns v1i64 = BITCAST i64 into v1i64 = BITCAST v2i32. // x86 this turns v1i64 = BITCAST i64 into v1i64 = BITCAST v2i32.
//
// FIXME: I'm not sure why we are first trying to split the input into
// a 2 element vector, so I'm leaving it here to maintain the current
// behavior.
unsigned NumElts = 2;
EVT OVT = N->getOperand(0).getValueType(); EVT OVT = N->getOperand(0).getValueType();
EVT NVT = EVT::getVectorVT(*DAG.getContext(), EVT NVT = EVT::getVectorVT(*DAG.getContext(),
TLI.getTypeToTransformTo(*DAG.getContext(), OVT), TLI.getTypeToTransformTo(*DAG.getContext(), OVT),
2); NumElts);
if (!isTypeLegal(NVT)) {
if (isTypeLegal(NVT)) { // If we can't find a legal type by splitting the integer in half,
SDValue Parts[2]; // then we can use the node's value type.
GetExpandedOp(N->getOperand(0), Parts[0], Parts[1]); NumElts = N->getValueType(0).getVectorNumElements();
NVT = N->getValueType(0);
if (TLI.isBigEndian())
std::swap(Parts[0], Parts[1]);
SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, NVT, Parts, 2);
return DAG.getNode(ISD::BITCAST, dl, N->getValueType(0), Vec);
} }
SmallVector<SDValue, 8> Ops;
IntegerToVector(N->getOperand(0), NumElts, Ops, NVT.getVectorElementType());
SDValue Vec = DAG.getNode(ISD::BUILD_VECTOR, dl, NVT, &Ops[0], NumElts);
return DAG.getNode(ISD::BITCAST, dl, N->getValueType(0), Vec);
} }
// Otherwise, store to a temporary and load out again as the new type. // Otherwise, store to a temporary and load out again as the new type.

15
test/CodeGen/R600/vselect64.ll Normal file
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@ -0,0 +1,15 @@
; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
; XXX: Merge this test into vselect.ll once SI supports 64-bit select.
; CHECK-LABEL: @test_select_v4i64
; Make sure the vectors aren't being stored on the stack. We know they are
; being stored on the stack if the shaders uses at leat 10 registers.
; CHECK-NOT: {{\**}} MOV T{{[0-9][0-9]}}.X
define void @test_select_v4i64(<4 x i64> addrspace(1)* %out, <4 x i32> %c) {
entry:
%cmp = icmp ne <4 x i32> %c, <i32 0, i32 0, i32 0, i32 0>
%result = select <4 x i1> %cmp, <4 x i64> <i64 0, i64 1, i64 2, i64 3>, <4 x i64> <i64 4, i64 5, i64 6, i64 7>
store <4 x i64> %result, <4 x i64> addrspace(1)* %out
ret void
}