6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-06-19 03:24:09 +00:00
Code Issues Projects Releases Wiki Activity

Masked Gather and Scatter Intrinsics.

Browse Source 
Gather and Scatter are new introduced intrinsics, comming after recently implemented masked load and store.
This is the first patch for Gather and Scatter intrinsics. It includes only the syntax, parsing and verification.

Gather and Scatter intrinsics allow to perform multiple memory accesses (read/write) in one vector instruction.
The intrinsics are not target specific and will have the following syntax:
Gather:
declare <16 x i32> @llvm.masked.gather.v16i32(<16 x i32*> <vector of ptrs>, i32 <alignment>, <16 x i1> <mask>, <16 x i32> <passthru>)
declare <8 x float> @llvm.masked.gather.v8f32(<8 x float*><vector of ptrs>, i32 <alignment>, <8 x i1> <mask>, <8 x float><passthru>)

Scatter:
declare void @llvm.masked.scatter.v8i32(<8 x i32><vector value to be stored> , <8 x i32*><vector of ptrs> , i32 <alignment>, <8 x i1> <mask>)
declare void @llvm.masked.scatter.v16i32(<16 x i32> <vector value to be stored> , <16 x i32*> <vector of ptrs>, i32 <alignment>, <16 x i1><mask> )

Vector of ptrs - a set of source/destination addresses, to load/store the value. 
Mask - switches on/off vector lanes to prevent memory access for switched-off lanes
vector of ptrs, value and mask should have the same vector width.

These are code examples where gather / scatter should be used and will allow function vectorization
;void foo1(int * restrict A, int * restrict B, int * restrict C) {
; for (int i=0; i<SIZE; i++) {
; A[i] = B[C[i]];
; }
;}

;void foo3(int * restrict A, int * restrict B) {
; for (int i=0; i<SIZE; i++) {
; A[B[i]] = i+5;
; }
;}

Tests will come in the following patches, with CodeGen and Vectorizer.

http://reviews.llvm.org/D7433



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@228521 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Elena Demikhovsky
2015-02-08 08:27:19 +00:00
parent b1ffebbbdb
commit 8be39c81b0
5 changed files with 58 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
lib/IR/Function.cpp
View File

@ -542,7 +542,8 @@ enum IIT_Info {
IIT_VARARG = 28,
IIT_HALF_VEC_ARG = 29,
IIT_SAME_VEC_WIDTH_ARG = 30,
IIT_PTR_TO_ARG = 31
IIT_PTR_TO_ARG = 31,
IIT_VEC_OF_PTRS_TO_ELT = 32
};
@ -662,6 +663,12 @@ static void DecodeIITType(unsigned &NextElt, ArrayRef<unsigned char> Infos,
ArgInfo));
return;
}
case IIT_VEC_OF_PTRS_TO_ELT: {
unsigned ArgInfo = (NextElt == Infos.size() ? 0 : Infos[NextElt++]);
OutputTable.push_back(IITDescriptor::get(IITDescriptor::VecOfPtrsToElt,
ArgInfo));
return;
}
case IIT_EMPTYSTRUCT:
OutputTable.push_back(IITDescriptor::get(IITDescriptor::Struct, 0));
return;
@ -781,6 +788,15 @@ static Type *DecodeFixedType(ArrayRef<Intrinsic::IITDescriptor> &Infos,
Type *Ty = Tys[D.getArgumentNumber()];
return PointerType::getUnqual(Ty);
}
case IITDescriptor::VecOfPtrsToElt: {
Type *Ty = Tys[D.getArgumentNumber()];
VectorType *VTy = dyn_cast<VectorType>(Ty);
if (!VTy)
llvm_unreachable("Expected an argument of Vector Type");
Type *EltTy = VTy->getVectorElementType();
return VectorType::get(PointerType::getUnqual(EltTy),
VTy->getNumElements());
}
}
llvm_unreachable("unhandled");
}