https://github.com/skc7 created https://github.com/llvm/llvm-project/pull/166731
This PR removes the named-barrier LDS lowering from `amdgpu-lower-module-lds` pass, since it is now handled by `amdgpu-lower-exec-sync` pass >From 0a2e9ee17ea82a7cb3fe191626ee84b05c37be83 Mon Sep 17 00:00:00 2001 From: skc7 <[email protected]> Date: Thu, 6 Nov 2025 14:29:17 +0530 Subject: [PATCH] [AMDGPU] Remove lowering named-barrier LDS logci from amdgpu-lower-module-lds --- .../AMDGPU/AMDGPULowerModuleLDSPass.cpp | 126 ------------------ 1 file changed, 126 deletions(-) diff --git a/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp index a4ef524c43466..3c0328e93ffbd 100644 --- a/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp +++ b/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp @@ -922,126 +922,6 @@ class AMDGPULowerModuleLDS { return KernelToCreatedDynamicLDS; } - static GlobalVariable *uniquifyGVPerKernel(Module &M, GlobalVariable *GV, - Function *KF) { - bool NeedsReplacement = false; - for (Use &U : GV->uses()) { - if (auto *I = dyn_cast<Instruction>(U.getUser())) { - Function *F = I->getFunction(); - if (isKernelLDS(F) && F != KF) { - NeedsReplacement = true; - break; - } - } - } - if (!NeedsReplacement) - return GV; - // Create a new GV used only by this kernel and its function - GlobalVariable *NewGV = new GlobalVariable( - M, GV->getValueType(), GV->isConstant(), GV->getLinkage(), - GV->getInitializer(), GV->getName() + "." + KF->getName(), nullptr, - GV->getThreadLocalMode(), GV->getType()->getAddressSpace()); - NewGV->copyAttributesFrom(GV); - for (Use &U : make_early_inc_range(GV->uses())) { - if (auto *I = dyn_cast<Instruction>(U.getUser())) { - Function *F = I->getFunction(); - if (!isKernelLDS(F) || F == KF) { - U.getUser()->replaceUsesOfWith(GV, NewGV); - } - } - } - return NewGV; - } - - bool lowerSpecialLDSVariables( - Module &M, LDSUsesInfoTy &LDSUsesInfo, - VariableFunctionMap &LDSToKernelsThatNeedToAccessItIndirectly) { - bool Changed = false; - const DataLayout &DL = M.getDataLayout(); - // The 1st round: give module-absolute assignments - int NumAbsolutes = 0; - std::vector<GlobalVariable *> OrderedGVs; - for (auto &K : LDSToKernelsThatNeedToAccessItIndirectly) { - GlobalVariable *GV = K.first; - if (!isNamedBarrier(*GV)) - continue; - // give a module-absolute assignment if it is indirectly accessed by - // multiple kernels. This is not precise, but we don't want to duplicate - // a function when it is called by multiple kernels. - if (LDSToKernelsThatNeedToAccessItIndirectly[GV].size() > 1) { - OrderedGVs.push_back(GV); - } else { - // leave it to the 2nd round, which will give a kernel-relative - // assignment if it is only indirectly accessed by one kernel - LDSUsesInfo.direct_access[*K.second.begin()].insert(GV); - } - LDSToKernelsThatNeedToAccessItIndirectly.erase(GV); - } - OrderedGVs = sortByName(std::move(OrderedGVs)); - for (GlobalVariable *GV : OrderedGVs) { - unsigned BarrierScope = llvm::AMDGPU::Barrier::BARRIER_SCOPE_WORKGROUP; - unsigned BarId = NumAbsolutes + 1; - unsigned BarCnt = DL.getTypeAllocSize(GV->getValueType()) / 16; - NumAbsolutes += BarCnt; - - // 4 bits for alignment, 5 bits for the barrier num, - // 3 bits for the barrier scope - unsigned Offset = 0x802000u | BarrierScope << 9 | BarId << 4; - recordLDSAbsoluteAddress(&M, GV, Offset); - } - OrderedGVs.clear(); - - // The 2nd round: give a kernel-relative assignment for GV that - // either only indirectly accessed by single kernel or only directly - // accessed by multiple kernels. - std::vector<Function *> OrderedKernels; - for (auto &K : LDSUsesInfo.direct_access) { - Function *F = K.first; - assert(isKernelLDS(F)); - OrderedKernels.push_back(F); - } - OrderedKernels = sortByName(std::move(OrderedKernels)); - - llvm::DenseMap<Function *, uint32_t> Kernel2BarId; - for (Function *F : OrderedKernels) { - for (GlobalVariable *GV : LDSUsesInfo.direct_access[F]) { - if (!isNamedBarrier(*GV)) - continue; - - LDSUsesInfo.direct_access[F].erase(GV); - if (GV->isAbsoluteSymbolRef()) { - // already assigned - continue; - } - OrderedGVs.push_back(GV); - } - OrderedGVs = sortByName(std::move(OrderedGVs)); - for (GlobalVariable *GV : OrderedGVs) { - // GV could also be used directly by other kernels. If so, we need to - // create a new GV used only by this kernel and its function. - auto NewGV = uniquifyGVPerKernel(M, GV, F); - Changed |= (NewGV != GV); - unsigned BarrierScope = llvm::AMDGPU::Barrier::BARRIER_SCOPE_WORKGROUP; - unsigned BarId = Kernel2BarId[F]; - BarId += NumAbsolutes + 1; - unsigned BarCnt = DL.getTypeAllocSize(GV->getValueType()) / 16; - Kernel2BarId[F] += BarCnt; - unsigned Offset = 0x802000u | BarrierScope << 9 | BarId << 4; - recordLDSAbsoluteAddress(&M, NewGV, Offset); - } - OrderedGVs.clear(); - } - // Also erase those special LDS variables from indirect_access. - for (auto &K : LDSUsesInfo.indirect_access) { - assert(isKernelLDS(K.first)); - for (GlobalVariable *GV : K.second) { - if (isNamedBarrier(*GV)) - K.second.erase(GV); - } - } - return Changed; - } - bool runOnModule(Module &M) { CallGraph CG = CallGraph(M); bool Changed = superAlignLDSGlobals(M); @@ -1064,12 +944,6 @@ class AMDGPULowerModuleLDS { } } - if (LDSUsesInfo.HasSpecialGVs) { - // Special LDS variables need special address assignment - Changed |= lowerSpecialLDSVariables( - M, LDSUsesInfo, LDSToKernelsThatNeedToAccessItIndirectly); - } - // Partition variables accessed indirectly into the different strategies DenseSet<GlobalVariable *> ModuleScopeVariables; DenseSet<GlobalVariable *> TableLookupVariables; _______________________________________________ llvm-branch-commits mailing list [email protected] https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
