[llvm] r241788 - Extended syntax of vector version of getelementptr instruction.
Elena Demikhovsky
elena.demikhovsky at intel.com
Thu Jul 9 00:42:49 PDT 2015
Author: delena
Date: Thu Jul 9 02:42:48 2015
New Revision: 241788
URL: http://llvm.org/viewvc/llvm-project?rev=241788&view=rev
Log:
Extended syntax of vector version of getelementptr instruction.
The justification of this change is here: http://lists.cs.uiuc.edu/pipermail/llvmdev/2015-March/082989.html
According to the current GEP syntax, vector GEP requires that each index must be a vector with the same number of elements.
%A = getelementptr i8, <4 x i8*> %ptrs, <4 x i64> %offsets
In this implementation I let each index be or vector or scalar. All vector indices must have the same number of elements. The scalar value will mean the splat vector value.
(1) %A = getelementptr i8, i8* %ptr, <4 x i64> %offsets
or
(2) %A = getelementptr i8, <4 x i8*> %ptrs, i64 %offset
In all cases the %A type is <4 x i8*>
In the case (2) we add the same offset to all pointers.
The case (1) covers C[B[i]] case, when we have the same base C and different offsets B[i].
The documentation is updated.
http://reviews.llvm.org/D10496
Modified:
llvm/trunk/docs/LangRef.rst
llvm/trunk/include/llvm/IR/Instructions.h
llvm/trunk/lib/AsmParser/LLParser.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/trunk/lib/IR/Verifier.cpp
llvm/trunk/test/Assembler/getelementptr_vec_idx1.ll
llvm/trunk/test/Assembler/getelementptr_vec_idx2.ll
llvm/trunk/test/Assembler/getelementptr_vec_idx3.ll
llvm/trunk/test/CodeGen/X86/vector-gep.ll
Modified: llvm/trunk/docs/LangRef.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.rst (original)
+++ llvm/trunk/docs/LangRef.rst Thu Jul 9 02:42:48 2015
@@ -6718,7 +6718,8 @@ Overview:
The '``getelementptr``' instruction is used to get the address of a
subelement of an :ref:`aggregate <t_aggregate>` data structure. It performs
-address calculation only and does not access memory.
+address calculation only and does not access memory. The instruction can also
+be used to calculate a vector of such addresses.
Arguments:
""""""""""
@@ -6844,12 +6845,61 @@ Example:
; yields i32*:iptr
%iptr = getelementptr [10 x i32], [10 x i32]* @arr, i16 0, i16 0
-In cases where the pointer argument is a vector of pointers, each index
-must be a vector with the same number of elements. For example:
+Vector of pointers:
+"""""""""""""""""""
+
+The ``getelementptr`` returns a vector of pointers, instead of a single address,
+when one or more of its arguments is a vector. In such cases, all vector
+arguments should have the same number of elements, and every scalar argument
+will be effectively broadcast into a vector during address calculation.
+
+.. code-block:: llvm
+
+ ; All arguments are vectors:
+ ; A[i] = ptrs[i] + offsets[i]*sizeof(i8)
+ %A = getelementptr i8, <4 x i8*> %ptrs, <4 x i64> %offsets
+
+ ; Add the same scalar offset to each pointer of a vector:
+ ; A[i] = ptrs[i] + offset*sizeof(i8)
+ %A = getelementptr i8, <4 x i8*> %ptrs, i64 %offset
+
+ ; Add distinct offsets to the same pointer:
+ ; A[i] = ptr + offsets[i]*sizeof(i8)
+ %A = getelementptr i8, i8* %ptr, <4 x i64> %offsets
+
+ ; In all cases described above the type of the result is <4 x i8*>
+
+The two following instructions are equivalent:
+
+.. code-block:: llvm
+
+ getelementptr %struct.ST, <4 x %struct.ST*> %s, <4 x i64> %ind1,
+ <4 x i32> <i32 2, i32 2, i32 2, i32 2>,
+ <4 x i32> <i32 1, i32 1, i32 1, i32 1>,
+ <4 x i32> %ind4,
+ <4 x i64> <i64 13, i64 13, i64 13, i64 13>
+
+ getelementptr %struct.ST, <4 x %struct.ST*> %s, <4 x i64> %ind1,
+ i32 2, i32 1, <4 x i32> %ind4, i64 13
+
+Let's look at the C code, where the vector version of ``getelementptr``
+makes sense:
+
+.. code-block:: c
+
+ // Let's assume that we vectorize the following loop:
+ double *A, B; int *C;
+ for (int i = 0; i < size; ++i) {
+ A[i] = B[C[i]];
+ }
.. code-block:: llvm
- %A = getelementptr i8, <4 x i8*> %ptrs, <4 x i64> %offsets,
+ ; get pointers for 8 elements from array B
+ %ptrs = getelementptr double, double* %B, <8 x i32> %C
+ ; load 8 elements from array B into A
+ %A = call <8 x double> @llvm.masked.gather.v8f64(<8 x double*> %ptrs,
+ i32 8, <8 x i1> %mask, <8 x double> %passthru)
Conversion Operations
---------------------
Modified: llvm/trunk/include/llvm/IR/Instructions.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Instructions.h?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/Instructions.h (original)
+++ llvm/trunk/include/llvm/IR/Instructions.h Thu Jul 9 02:42:48 2015
@@ -990,10 +990,14 @@ public:
Ptr->getType()->getPointerAddressSpace());
// Vector GEP
if (Ptr->getType()->isVectorTy()) {
- unsigned NumElem = cast<VectorType>(Ptr->getType())->getNumElements();
+ unsigned NumElem = Ptr->getType()->getVectorNumElements();
return VectorType::get(PtrTy, NumElem);
}
-
+ for (Value *Index : IdxList)
+ if (Index->getType()->isVectorTy()) {
+ unsigned NumElem = Index->getType()->getVectorNumElements();
+ return VectorType::get(PtrTy, NumElem);
+ }
// Scalar GEP
return PtrTy;
}
Modified: llvm/trunk/lib/AsmParser/LLParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLParser.cpp?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/lib/AsmParser/LLParser.cpp (original)
+++ llvm/trunk/lib/AsmParser/LLParser.cpp Thu Jul 9 02:42:48 2015
@@ -2873,8 +2873,8 @@ bool LLParser::ParseValID(ValID &ID, Per
if (ValTy->isVectorTy() != BaseType->isVectorTy())
return Error(ID.Loc, "getelementptr index type missmatch");
if (ValTy->isVectorTy()) {
- unsigned ValNumEl = cast<VectorType>(ValTy)->getNumElements();
- unsigned PtrNumEl = cast<VectorType>(BaseType)->getNumElements();
+ unsigned ValNumEl = ValTy->getVectorNumElements();
+ unsigned PtrNumEl = BaseType->getVectorNumElements();
if (ValNumEl != PtrNumEl)
return Error(
ID.Loc,
@@ -5572,6 +5572,11 @@ int LLParser::ParseGetElementPtr(Instruc
SmallVector<Value*, 16> Indices;
bool AteExtraComma = false;
+ // GEP returns a vector of pointers if at least one of parameters is a vector.
+ // All vector parameters should have the same vector width.
+ unsigned GEPWidth = BaseType->isVectorTy() ?
+ BaseType->getVectorNumElements() : 0;
+
while (EatIfPresent(lltok::comma)) {
if (Lex.getKind() == lltok::MetadataVar) {
AteExtraComma = true;
@@ -5580,14 +5585,13 @@ int LLParser::ParseGetElementPtr(Instruc
if (ParseTypeAndValue(Val, EltLoc, PFS)) return true;
if (!Val->getType()->getScalarType()->isIntegerTy())
return Error(EltLoc, "getelementptr index must be an integer");
- if (Val->getType()->isVectorTy() != Ptr->getType()->isVectorTy())
- return Error(EltLoc, "getelementptr index type missmatch");
+
if (Val->getType()->isVectorTy()) {
- unsigned ValNumEl = cast<VectorType>(Val->getType())->getNumElements();
- unsigned PtrNumEl = cast<VectorType>(Ptr->getType())->getNumElements();
- if (ValNumEl != PtrNumEl)
+ unsigned ValNumEl = Val->getType()->getVectorNumElements();
+ if (GEPWidth && GEPWidth != ValNumEl)
return Error(EltLoc,
"getelementptr vector index has a wrong number of elements");
+ GEPWidth = ValNumEl;
}
Indices.push_back(Val);
}
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Thu Jul 9 02:42:48 2015
@@ -2787,6 +2787,16 @@ void SelectionDAGBuilder::visitGetElemen
SDValue N = getValue(Op0);
SDLoc dl = getCurSDLoc();
+ // Normalize Vector GEP - all scalar operands should be converted to the
+ // splat vector.
+ unsigned VectorWidth = I.getType()->isVectorTy() ?
+ cast<VectorType>(I.getType())->getVectorNumElements() : 0;
+
+ if (VectorWidth && !N.getValueType().isVector()) {
+ MVT VT = MVT::getVectorVT(N.getValueType().getSimpleVT(), VectorWidth);
+ SmallVector<SDValue, 16> Ops(VectorWidth, N);
+ N = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, Ops);
+ }
for (GetElementPtrInst::const_op_iterator OI = I.op_begin()+1, E = I.op_end();
OI != E; ++OI) {
const Value *Idx = *OI;
@@ -2807,12 +2817,20 @@ void SelectionDAGBuilder::visitGetElemen
unsigned PtrSize = PtrTy.getSizeInBits();
APInt ElementSize(PtrSize, DL->getTypeAllocSize(Ty));
- // If this is a constant subscript, handle it quickly.
- if (const auto *CI = dyn_cast<ConstantInt>(Idx)) {
+ // If this is a scalar constant or a splat vector of constants,
+ // handle it quickly.
+ const auto *CI = dyn_cast<ConstantInt>(Idx);
+ if (!CI && isa<ConstantDataVector>(Idx) &&
+ cast<ConstantDataVector>(Idx)->getSplatValue())
+ CI = cast<ConstantInt>(cast<ConstantDataVector>(Idx)->getSplatValue());
+
+ if (CI) {
if (CI->isZero())
continue;
APInt Offs = ElementSize * CI->getValue().sextOrTrunc(PtrSize);
- SDValue OffsVal = DAG.getConstant(Offs, dl, PtrTy);
+ SDValue OffsVal = VectorWidth ?
+ DAG.getConstant(Offs, dl, MVT::getVectorVT(PtrTy, VectorWidth)) :
+ DAG.getConstant(Offs, dl, PtrTy);
N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N, OffsVal);
continue;
}
@@ -2820,6 +2838,11 @@ void SelectionDAGBuilder::visitGetElemen
// N = N + Idx * ElementSize;
SDValue IdxN = getValue(Idx);
+ if (!IdxN.getValueType().isVector() && VectorWidth) {
+ MVT VT = MVT::getVectorVT(IdxN.getValueType().getSimpleVT(), VectorWidth);
+ SmallVector<SDValue, 16> Ops(VectorWidth, IdxN);
+ IdxN = DAG.getNode(ISD::BUILD_VECTOR, dl, VT, Ops);
+ }
// If the index is smaller or larger than intptr_t, truncate or extend
// it.
IdxN = DAG.getSExtOrTrunc(IdxN, dl, N.getValueType());
Modified: llvm/trunk/lib/IR/Verifier.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/Verifier.cpp?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/lib/IR/Verifier.cpp (original)
+++ llvm/trunk/lib/IR/Verifier.cpp Thu Jul 9 02:42:48 2015
@@ -2538,10 +2538,6 @@ void Verifier::visitGetElementPtrInst(Ge
Assert(isa<PointerType>(TargetTy),
"GEP base pointer is not a vector or a vector of pointers", &GEP);
Assert(GEP.getSourceElementType()->isSized(), "GEP into unsized type!", &GEP);
- Assert(GEP.getPointerOperandType()->isVectorTy() ==
- GEP.getType()->isVectorTy(),
- "Vector GEP must return a vector value", &GEP);
-
SmallVector<Value*, 16> Idxs(GEP.idx_begin(), GEP.idx_end());
Type *ElTy =
GetElementPtrInst::getIndexedType(GEP.getSourceElementType(), Idxs);
@@ -2551,17 +2547,20 @@ void Verifier::visitGetElementPtrInst(Ge
GEP.getResultElementType() == ElTy,
"GEP is not of right type for indices!", &GEP, ElTy);
- if (GEP.getPointerOperandType()->isVectorTy()) {
+ if (GEP.getType()->isVectorTy()) {
// Additional checks for vector GEPs.
- unsigned GepWidth = GEP.getPointerOperandType()->getVectorNumElements();
- Assert(GepWidth == GEP.getType()->getVectorNumElements(),
- "Vector GEP result width doesn't match operand's", &GEP);
+ unsigned GEPWidth = GEP.getType()->getVectorNumElements();
+ if (GEP.getPointerOperandType()->isVectorTy())
+ Assert(GEPWidth == GEP.getPointerOperandType()->getVectorNumElements(),
+ "Vector GEP result width doesn't match operand's", &GEP);
for (unsigned i = 0, e = Idxs.size(); i != e; ++i) {
Type *IndexTy = Idxs[i]->getType();
- Assert(IndexTy->isVectorTy(), "Vector GEP must have vector indices!",
- &GEP);
- unsigned IndexWidth = IndexTy->getVectorNumElements();
- Assert(IndexWidth == GepWidth, "Invalid GEP index vector width", &GEP);
+ if (IndexTy->isVectorTy()) {
+ unsigned IndexWidth = IndexTy->getVectorNumElements();
+ Assert(IndexWidth == GEPWidth, "Invalid GEP index vector width", &GEP);
+ }
+ Assert(IndexTy->getScalarType()->isIntegerTy(),
+ "All GEP indices should be of integer type");
}
}
visitInstruction(GEP);
Modified: llvm/trunk/test/Assembler/getelementptr_vec_idx1.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/getelementptr_vec_idx1.ll?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/test/Assembler/getelementptr_vec_idx1.ll (original)
+++ llvm/trunk/test/Assembler/getelementptr_vec_idx1.ll Thu Jul 9 02:42:48 2015
@@ -1,8 +1,8 @@
; RUN: not llvm-as < %s >/dev/null 2> %t
; RUN: FileCheck %s < %t
-; Test that a vector index is only used with a vector pointer.
+; Test that a vector GEP may be used with a scalar base, the result is a vector of pointers
-; CHECK: getelementptr index type missmatch
+; CHECK: '%w' defined with type '<2 x i32*>
define i32 @test(i32* %a) {
%w = getelementptr i32, i32* %a, <2 x i32> <i32 5, i32 9>
Modified: llvm/trunk/test/Assembler/getelementptr_vec_idx2.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/getelementptr_vec_idx2.ll?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/test/Assembler/getelementptr_vec_idx2.ll (original)
+++ llvm/trunk/test/Assembler/getelementptr_vec_idx2.ll Thu Jul 9 02:42:48 2015
@@ -1,10 +1,24 @@
; RUN: not llvm-as < %s >/dev/null 2> %t
; RUN: FileCheck %s < %t
-; Test that a vector pointer is only used with a vector index.
+; Test that a vector pointer may be used with a scalar index.
+; Test that a vector pointer and vector index should have the same vector width
-; CHECK: getelementptr index type missmatch
-
-define <2 x i32> @test(<2 x i32*> %a) {
+; This code is correct
+define <2 x i32*> @test2(<2 x i32*> %a) {
%w = getelementptr i32, <2 x i32*> %a, i32 2
+ ret <2 x i32*> %w
+}
+
+; This code is correct
+define <2 x i32*> @test3(i32* %a) {
+ %w = getelementptr i32, i32* %a, <2 x i32> <i32 2, i32 2>
+ ret <2 x i32*> %w
+}
+
+; CHECK: getelementptr vector index has a wrong number of elements
+
+define <2 x i32> @test1(<2 x i32*> %a) {
+ %w = getelementptr i32, <2 x i32*> %a, <4 x i32><i32 2, i32 2, i32 2, i32 2>
ret <2 x i32> %w
}
+
Modified: llvm/trunk/test/Assembler/getelementptr_vec_idx3.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Assembler/getelementptr_vec_idx3.ll?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/test/Assembler/getelementptr_vec_idx3.ll (original)
+++ llvm/trunk/test/Assembler/getelementptr_vec_idx3.ll Thu Jul 9 02:42:48 2015
@@ -1,8 +1,8 @@
; RUN: not llvm-as < %s >/dev/null 2> %t
; RUN: FileCheck %s < %t
-; Test that vector indices have the same number of elements as the pointer.
+; Test that a vector GEP may be used with a scalar base, the result is a vector of pointers
-; CHECK: getelementptr index type missmatch
+; CHECK: '%w' defined with type '<2 x <4 x i32>*>'
define <4 x i32> @test(<4 x i32>* %a) {
%w = getelementptr <4 x i32>, <4 x i32>* %a, <2 x i32> <i32 5, i32 9>
Modified: llvm/trunk/test/CodeGen/X86/vector-gep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/vector-gep.ll?rev=241788&r1=241787&r2=241788&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/vector-gep.ll (original)
+++ llvm/trunk/test/CodeGen/X86/vector-gep.ll Thu Jul 9 02:42:48 2015
@@ -92,3 +92,25 @@ entry:
;CHECK: ret
}
+;CHECK-LABEL: AGEP7:
+define <4 x i8*> @AGEP7(<4 x i8*> %param, i32 %off) nounwind {
+entry:
+;CHECK: vbroadcastss
+;CHECK: vpadd
+ %A = getelementptr i8, <4 x i8*> %param, i32 %off
+ ret <4 x i8*> %A
+;CHECK: ret
+}
+
+;CHECK-LABEL: AGEP8:
+define <4 x i16*> @AGEP8(i16* %param, <4 x i32> %off) nounwind {
+entry:
+; Multiply offset by two (add it to itself).
+;CHECK: vpadd
+; add the base to the offset
+;CHECK: vbroadcastss
+;CHECK-NEXT: vpadd
+ %A = getelementptr i16, i16* %param, <4 x i32> %off
+ ret <4 x i16*> %A
+;CHECK: ret
+}
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