vendor/llvm-project/llvmorg-17-init-19304-gd0b54bb50e51

1 files changed, 98 insertions, 0 deletions

diff --git a/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.cpp b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.cpp
new file mode 100644
index 000000000000..b4f7e78cb107
--- /dev/null
+++ b/llvm/lib/Target/NVPTX/NVPTXAliasAnalysis.cpp
@@ -0,0 +1,98 @@
+//===--------------------- NVPTXAliasAnalysis.cpp--------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This is the NVPTX address space based alias analysis pass.
+//===----------------------------------------------------------------------===//
+
+#include "NVPTXAliasAnalysis.h"
+#include "MCTargetDesc/NVPTXBaseInfo.h"
+#include "NVPTX.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/CallingConv.h"
+#include "llvm/IR/Instructions.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "NVPTX-aa"
+
+AnalysisKey NVPTXAA::Key;
+
+char NVPTXAAWrapperPass::ID = 0;
+char NVPTXExternalAAWrapper::ID = 0;
+
+INITIALIZE_PASS(NVPTXAAWrapperPass, "nvptx-aa",
+                "NVPTX Address space based Alias Analysis", false, true)
+
+INITIALIZE_PASS(NVPTXExternalAAWrapper, "nvptx-aa-wrapper",
+                "NVPTX Address space based Alias Analysis Wrapper", false, true)
+
+ImmutablePass *llvm::createNVPTXAAWrapperPass() {
+  return new NVPTXAAWrapperPass();
+}
+
+ImmutablePass *llvm::createNVPTXExternalAAWrapperPass() {
+  return new NVPTXExternalAAWrapper();
+}
+
+NVPTXAAWrapperPass::NVPTXAAWrapperPass() : ImmutablePass(ID) {
+  initializeNVPTXAAWrapperPassPass(*PassRegistry::getPassRegistry());
+}
+
+void NVPTXAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
+  AU.setPreservesAll();
+}
+
+static AliasResult::Kind getAliasResult(unsigned AS1, unsigned AS2) {
+  if ((AS1 == ADDRESS_SPACE_GENERIC) || (AS2 == ADDRESS_SPACE_GENERIC))
+    return AliasResult::MayAlias;
+
+  // PTX s6.4.1.1. Generic Addressing:
+  // A generic address maps to global memory unless it falls within
+  // the window for const, local, or shared memory. The Kernel
+  // Function Parameters (.param) window is contained within the
+  // .global window.
+  //
+  // Therefore a global pointer may alias with a param pointer on some
+  // GPUs via addrspacecast(param->generic->global) when cvta.param
+  // instruction is used (PTX 7.7+ and SM_70+).
+  //
+  // TODO: cvta.param is not yet supported. We need to change aliasing
+  // rules once it is added.
+
+  return (AS1 == AS2 ? AliasResult::MayAlias : AliasResult::NoAlias);
+}
+
+AliasResult NVPTXAAResult::alias(const MemoryLocation &Loc1,
+                                 const MemoryLocation &Loc2, AAQueryInfo &AAQI,
+                                 const Instruction *) {
+  unsigned AS1 = Loc1.Ptr->getType()->getPointerAddressSpace();
+  unsigned AS2 = Loc2.Ptr->getType()->getPointerAddressSpace();
+
+  return getAliasResult(AS1, AS2);
+}
+
+// TODO: .param address space may be writable in presence of cvta.param, but
+// this instruction is currently not supported. NVPTXLowerArgs also does not
+// allow any writes to .param pointers.
+static bool isConstOrParam(unsigned AS) {
+  return AS == AddressSpace::ADDRESS_SPACE_CONST ||
+         AS == AddressSpace::ADDRESS_SPACE_PARAM;
+}
+
+ModRefInfo NVPTXAAResult::getModRefInfoMask(const MemoryLocation &Loc,
+                                            AAQueryInfo &AAQI,
+                                            bool IgnoreLocals) {
+  if (isConstOrParam(Loc.Ptr->getType()->getPointerAddressSpace()))
+    return ModRefInfo::NoModRef;
+
+  const Value *Base = getUnderlyingObject(Loc.Ptr);
+  if (isConstOrParam(Base->getType()->getPointerAddressSpace()))
+    return ModRefInfo::NoModRef;
+
+  return AAResultBase::getModRefInfoMask(Loc, AAQI, IgnoreLocals);
+}