LLVM 20.0.0git
NVPTXAliasAnalysis.cpp
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1//===--------------------- NVPTXAliasAnalysis.cpp--------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8/// \file
9/// This is the NVPTX address space based alias analysis pass.
10//===----------------------------------------------------------------------===//
11
12#include "NVPTXAliasAnalysis.h"
14#include "NVPTX.h"
16#include "llvm/IR/CallingConv.h"
18
19using namespace llvm;
20
21#define DEBUG_TYPE "NVPTX-aa"
22
23AnalysisKey NVPTXAA::Key;
24
27
29 "NVPTX Address space based Alias Analysis", false, true)
30
32 "NVPTX Address space based Alias Analysis Wrapper", false, true)
33
35 return new NVPTXAAWrapperPass();
36}
37
39 return new NVPTXExternalAAWrapper();
40}
41
44}
45
47 AU.setPreservesAll();
48}
49
50static AliasResult::Kind getAliasResult(unsigned AS1, unsigned AS2) {
51 if ((AS1 == ADDRESS_SPACE_GENERIC) || (AS2 == ADDRESS_SPACE_GENERIC))
53
54 // PTX s6.4.1.1. Generic Addressing:
55 // A generic address maps to global memory unless it falls within
56 // the window for const, local, or shared memory. The Kernel
57 // Function Parameters (.param) window is contained within the
58 // .global window.
59 //
60 // Therefore a global pointer may alias with a param pointer on some
61 // GPUs via addrspacecast(param->generic->global) when cvta.param
62 // instruction is used (PTX 7.7+ and SM_70+).
63 //
64 // TODO: cvta.param is not yet supported. We need to change aliasing
65 // rules once it is added.
66
67 return (AS1 == AS2 ? AliasResult::MayAlias : AliasResult::NoAlias);
68}
69
71 const MemoryLocation &Loc2, AAQueryInfo &AAQI,
72 const Instruction *) {
73 unsigned AS1 = Loc1.Ptr->getType()->getPointerAddressSpace();
74 unsigned AS2 = Loc2.Ptr->getType()->getPointerAddressSpace();
75
76 return getAliasResult(AS1, AS2);
77}
78
79// TODO: .param address space may be writable in presence of cvta.param, but
80// this instruction is currently not supported. NVPTXLowerArgs also does not
81// allow any writes to .param pointers.
82static bool isConstOrParam(unsigned AS) {
85}
86
88 AAQueryInfo &AAQI,
89 bool IgnoreLocals) {
92
93 const Value *Base = getUnderlyingObject(Loc.Ptr);
94 if (isConstOrParam(Base->getType()->getPointerAddressSpace()))
96
97 return ModRefInfo::ModRef;
98}
basic Basic Alias true
block Block Frequency Analysis
nvptx aa NVPTX Address space based Alias Analysis Wrapper
static AliasResult::Kind getAliasResult(unsigned AS1, unsigned AS2)
nvptx aa wrapper
static bool isConstOrParam(unsigned AS)
This is the NVPTX address space based alias analysis pass.
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
Definition: PassSupport.h:38
This class stores info we want to provide to or retain within an alias query.
The possible results of an alias query.
Definition: AliasAnalysis.h:77
@ MayAlias
The two locations may or may not alias.
Definition: AliasAnalysis.h:98
@ NoAlias
The two locations do not alias at all.
Definition: AliasAnalysis.h:95
Represent the analysis usage information of a pass.
void setPreservesAll()
Set by analyses that do not transform their input at all.
ImmutablePass class - This class is used to provide information that does not need to be run.
Definition: Pass.h:281
Representation for a specific memory location.
const Value * Ptr
The address of the start of the location.
AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB, AAQueryInfo &AAQI, const Instruction *CtxI=nullptr)
ModRefInfo getModRefInfoMask(const MemoryLocation &Loc, AAQueryInfo &AAQI, bool IgnoreLocals)
Legacy wrapper pass to provide the NVPTXAAResult object.
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - This function should be overriden by passes that need analysis information to do t...
static PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
unsigned getPointerAddressSpace() const
Get the address space of this pointer or pointer vector type.
LLVM Value Representation.
Definition: Value.h:74
Type * getType() const
All values are typed, get the type of this value.
Definition: Value.h:255
TargetPassConfig.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
@ ADDRESS_SPACE_GENERIC
Definition: NVPTXBaseInfo.h:22
@ ADDRESS_SPACE_CONST
Definition: NVPTXBaseInfo.h:25
@ ADDRESS_SPACE_PARAM
Definition: NVPTXBaseInfo.h:29
const Value * getUnderlyingObject(const Value *V, unsigned MaxLookup=6)
This method strips off any GEP address adjustments, pointer casts or llvm.threadlocal....
ImmutablePass * createNVPTXExternalAAWrapperPass()
void initializeNVPTXAAWrapperPassPass(PassRegistry &)
ModRefInfo
Flags indicating whether a memory access modifies or references memory.
Definition: ModRef.h:27
@ ModRef
The access may reference and may modify the value stored in memory.
@ NoModRef
The access neither references nor modifies the value stored in memory.
ImmutablePass * createNVPTXAAWrapperPass()
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: Analysis.h:28