1 files changed, 250 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp b/contrib/llvm-project/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp
new file mode 100644
index 000000000000..c34c12ab9fec
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/Target/AMDGPU/AMDGPULowerKernelArguments.cpp
@@ -0,0 +1,250 @@
+//===-- AMDGPULowerKernelArguments.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 pass replaces accesses to kernel arguments with loads from
+/// offsets from the kernarg base pointer.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AMDGPU.h"
+#include "GCNSubtarget.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/IR/IntrinsicsAMDGPU.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/Target/TargetMachine.h"
+#define DEBUG_TYPE "amdgpu-lower-kernel-arguments"
+
+using namespace llvm;
+
+namespace {
+
+class AMDGPULowerKernelArguments : public FunctionPass{
+public:
+  static char ID;
+
+  AMDGPULowerKernelArguments() : FunctionPass(ID) {}
+
+  bool runOnFunction(Function &F) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<TargetPassConfig>();
+    AU.setPreservesAll();
+ }
+};
+
+} // end anonymous namespace
+
+// skip allocas
+static BasicBlock::iterator getInsertPt(BasicBlock &BB) {
+  BasicBlock::iterator InsPt = BB.getFirstInsertionPt();
+  for (BasicBlock::iterator E = BB.end(); InsPt != E; ++InsPt) {
+    AllocaInst *AI = dyn_cast<AllocaInst>(&*InsPt);
+
+    // If this is a dynamic alloca, the value may depend on the loaded kernargs,
+    // so loads will need to be inserted before it.
+    if (!AI || !AI->isStaticAlloca())
+      break;
+  }
+
+  return InsPt;
+}
+
+bool AMDGPULowerKernelArguments::runOnFunction(Function &F) {
+  CallingConv::ID CC = F.getCallingConv();
+  if (CC != CallingConv::AMDGPU_KERNEL || F.arg_empty())
+    return false;
+
+  auto &TPC = getAnalysis<TargetPassConfig>();
+
+  const TargetMachine &TM = TPC.getTM<TargetMachine>();
+  const GCNSubtarget &ST = TM.getSubtarget<GCNSubtarget>(F);
+  LLVMContext &Ctx = F.getParent()->getContext();
+  const DataLayout &DL = F.getParent()->getDataLayout();
+  BasicBlock &EntryBlock = *F.begin();
+  IRBuilder<> Builder(&*getInsertPt(EntryBlock));
+
+  const Align KernArgBaseAlign(16); // FIXME: Increase if necessary
+  const uint64_t BaseOffset = ST.getExplicitKernelArgOffset(F);
+
+  Align MaxAlign;
+  // FIXME: Alignment is broken broken with explicit arg offset.;
+  const uint64_t TotalKernArgSize = ST.getKernArgSegmentSize(F, MaxAlign);
+  if (TotalKernArgSize == 0)
+    return false;
+
+  CallInst *KernArgSegment =
+      Builder.CreateIntrinsic(Intrinsic::amdgcn_kernarg_segment_ptr, {}, {},
+                              nullptr, F.getName() + ".kernarg.segment");
+
+  KernArgSegment->addRetAttr(Attribute::NonNull);
+  KernArgSegment->addRetAttr(
+      Attribute::getWithDereferenceableBytes(Ctx, TotalKernArgSize));
+
+  unsigned AS = KernArgSegment->getType()->getPointerAddressSpace();
+  uint64_t ExplicitArgOffset = 0;
+
+  for (Argument &Arg : F.args()) {
+    const bool IsByRef = Arg.hasByRefAttr();
+    Type *ArgTy = IsByRef ? Arg.getParamByRefType() : Arg.getType();
+    MaybeAlign ABITypeAlign = IsByRef ? Arg.getParamAlign() : None;
+    if (!ABITypeAlign)
+      ABITypeAlign = DL.getABITypeAlign(ArgTy);
+
+    uint64_t Size = DL.getTypeSizeInBits(ArgTy);
+    uint64_t AllocSize = DL.getTypeAllocSize(ArgTy);
+
+    uint64_t EltOffset = alignTo(ExplicitArgOffset, ABITypeAlign) + BaseOffset;
+    ExplicitArgOffset = alignTo(ExplicitArgOffset, ABITypeAlign) + AllocSize;
+
+    if (Arg.use_empty())
+      continue;
+
+    // If this is byval, the loads are already explicit in the function. We just
+    // need to rewrite the pointer values.
+    if (IsByRef) {
+      Value *ArgOffsetPtr = Builder.CreateConstInBoundsGEP1_64(
+          Builder.getInt8Ty(), KernArgSegment, EltOffset,
+          Arg.getName() + ".byval.kernarg.offset");
+
+      Value *CastOffsetPtr = Builder.CreatePointerBitCastOrAddrSpaceCast(
+          ArgOffsetPtr, Arg.getType());
+      Arg.replaceAllUsesWith(CastOffsetPtr);
+      continue;
+    }
+
+    if (PointerType *PT = dyn_cast<PointerType>(ArgTy)) {
+      // FIXME: Hack. We rely on AssertZext to be able to fold DS addressing
+      // modes on SI to know the high bits are 0 so pointer adds don't wrap. We
+      // can't represent this with range metadata because it's only allowed for
+      // integer types.
+      if ((PT->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS ||
+           PT->getAddressSpace() == AMDGPUAS::REGION_ADDRESS) &&
+          !ST.hasUsableDSOffset())
+        continue;
+
+      // FIXME: We can replace this with equivalent alias.scope/noalias
+      // metadata, but this appears to be a lot of work.
+      if (Arg.hasNoAliasAttr())
+        continue;
+    }
+
+    auto *VT = dyn_cast<FixedVectorType>(ArgTy);
+    bool IsV3 = VT && VT->getNumElements() == 3;
+    bool DoShiftOpt = Size < 32 && !ArgTy->isAggregateType();
+
+    VectorType *V4Ty = nullptr;
+
+    int64_t AlignDownOffset = alignDown(EltOffset, 4);
+    int64_t OffsetDiff = EltOffset - AlignDownOffset;
+    Align AdjustedAlign = commonAlignment(
+        KernArgBaseAlign, DoShiftOpt ? AlignDownOffset : EltOffset);
+
+    Value *ArgPtr;
+    Type *AdjustedArgTy;
+    if (DoShiftOpt) { // FIXME: Handle aggregate types
+      // Since we don't have sub-dword scalar loads, avoid doing an extload by
+      // loading earlier than the argument address, and extracting the relevant
+      // bits.
+      //
+      // Additionally widen any sub-dword load to i32 even if suitably aligned,
+      // so that CSE between different argument loads works easily.
+      ArgPtr = Builder.CreateConstInBoundsGEP1_64(
+          Builder.getInt8Ty(), KernArgSegment, AlignDownOffset,
+          Arg.getName() + ".kernarg.offset.align.down");
+      AdjustedArgTy = Builder.getInt32Ty();
+    } else {
+      ArgPtr = Builder.CreateConstInBoundsGEP1_64(
+          Builder.getInt8Ty(), KernArgSegment, EltOffset,
+          Arg.getName() + ".kernarg.offset");
+      AdjustedArgTy = ArgTy;
+    }
+
+    if (IsV3 && Size >= 32) {
+      V4Ty = FixedVectorType::get(VT->getElementType(), 4);
+      // Use the hack that clang uses to avoid SelectionDAG ruining v3 loads
+      AdjustedArgTy = V4Ty;
+    }
+
+    ArgPtr = Builder.CreateBitCast(ArgPtr, AdjustedArgTy->getPointerTo(AS),
+                                   ArgPtr->getName() + ".cast");
+    LoadInst *Load =
+        Builder.CreateAlignedLoad(AdjustedArgTy, ArgPtr, AdjustedAlign);
+    Load->setMetadata(LLVMContext::MD_invariant_load, MDNode::get(Ctx, {}));
+
+    MDBuilder MDB(Ctx);
+
+    if (isa<PointerType>(ArgTy)) {
+      if (Arg.hasNonNullAttr())
+        Load->setMetadata(LLVMContext::MD_nonnull, MDNode::get(Ctx, {}));
+
+      uint64_t DerefBytes = Arg.getDereferenceableBytes();
+      if (DerefBytes != 0) {
+        Load->setMetadata(
+          LLVMContext::MD_dereferenceable,
+          MDNode::get(Ctx,
+                      MDB.createConstant(
+                        ConstantInt::get(Builder.getInt64Ty(), DerefBytes))));
+      }
+
+      uint64_t DerefOrNullBytes = Arg.getDereferenceableOrNullBytes();
+      if (DerefOrNullBytes != 0) {
+        Load->setMetadata(
+          LLVMContext::MD_dereferenceable_or_null,
+          MDNode::get(Ctx,
+                      MDB.createConstant(ConstantInt::get(Builder.getInt64Ty(),
+                                                          DerefOrNullBytes))));
+      }
+
+      unsigned ParamAlign = Arg.getParamAlignment();
+      if (ParamAlign != 0) {
+        Load->setMetadata(
+          LLVMContext::MD_align,
+          MDNode::get(Ctx,
+                      MDB.createConstant(ConstantInt::get(Builder.getInt64Ty(),
+                                                          ParamAlign))));
+      }
+    }
+
+    // TODO: Convert noalias arg to !noalias
+
+    if (DoShiftOpt) {
+      Value *ExtractBits = OffsetDiff == 0 ?
+        Load : Builder.CreateLShr(Load, OffsetDiff * 8);
+
+      IntegerType *ArgIntTy = Builder.getIntNTy(Size);
+      Value *Trunc = Builder.CreateTrunc(ExtractBits, ArgIntTy);
+      Value *NewVal = Builder.CreateBitCast(Trunc, ArgTy,
+                                            Arg.getName() + ".load");
+      Arg.replaceAllUsesWith(NewVal);
+    } else if (IsV3) {
+      Value *Shuf = Builder.CreateShuffleVector(Load, ArrayRef<int>{0, 1, 2},
+                                                Arg.getName() + ".load");
+      Arg.replaceAllUsesWith(Shuf);
+    } else {
+      Load->setName(Arg.getName() + ".load");
+      Arg.replaceAllUsesWith(Load);
+    }
+  }
+
+  KernArgSegment->addRetAttr(
+      Attribute::getWithAlignment(Ctx, std::max(KernArgBaseAlign, MaxAlign)));
+
+  return true;
+}
+
+INITIALIZE_PASS_BEGIN(AMDGPULowerKernelArguments, DEBUG_TYPE,
+                      "AMDGPU Lower Kernel Arguments", false, false)
+INITIALIZE_PASS_END(AMDGPULowerKernelArguments, DEBUG_TYPE, "AMDGPU Lower Kernel Arguments",
+                    false, false)
+
+char AMDGPULowerKernelArguments::ID = 0;
+
+FunctionPass *llvm::createAMDGPULowerKernelArgumentsPass() {
+  return new AMDGPULowerKernelArguments();
+}