[X86][AMX] remove related code of X86PreAMXConfigPass

[yubingex007-a11y]

In https://reviews.llvm.org/D125075, we switched to use FastPreTileConfig in O0 and abandoned X86PreAMXConfigPass.
we can remove related code of X86PreAMXConfigPass safely.

[llvmbot]

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-backend-x86

Author: None (yubingex007-a11y)

Changes

In https://reviews.llvm.org/D125075, we switched to use FastPreTileConfig in O0 and abandoned X86PreAMXConfigPass.

---

Patch is 34.12 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/69569.diff

9 Files Affected:

• (modified) clang/docs/tools/clang-formatted-files.txt (-1)
• (modified) llvm/include/llvm/CodeGen/Passes.h (-3)
• (modified) llvm/lib/Target/X86/CMakeLists.txt (-1)
• (modified) llvm/lib/Target/X86/X86.h (-1)
• (removed) llvm/lib/Target/X86/X86PreAMXConfig.cpp (-415)
• (modified) llvm/lib/Target/X86/X86TargetMachine.cpp (-1)
• (removed) llvm/test/CodeGen/X86/AMX/amx-configO2toO0-precfg.ll (-178)
• (modified) llvm/tools/opt/opt.cpp (-1)
• (modified) llvm/utils/gn/secondary/llvm/lib/Target/X86/BUILD.gn (-1)

diff --git a/clang/docs/tools/clang-formatted-files.txt b/clang/docs/tools/clang-formatted-files.txt
index 16f84727117e28d..48cd800bffd0046 100644
--- a/clang/docs/tools/clang-formatted-files.txt
+++ b/clang/docs/tools/clang-formatted-files.txt
@@ -6813,7 +6813,6 @@ llvm/lib/Target/X86/X86LoadValueInjectionRetHardening.cpp
 llvm/lib/Target/X86/X86LowerAMXIntrinsics.cpp
 llvm/lib/Target/X86/X86LowerAMXType.cpp
 llvm/lib/Target/X86/X86LowerTileCopy.cpp
-llvm/lib/Target/X86/X86PreAMXConfig.cpp
 llvm/lib/Target/X86/X86PreTileConfig.cpp
 llvm/lib/Target/X86/X86RegisterBankInfo.h
 llvm/lib/Target/X86/X86ShuffleDecodeConstantPool.cpp
diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h
index 598c0b838c1b97d..8d14eef949e91b4 100644
--- a/llvm/include/llvm/CodeGen/Passes.h
+++ b/llvm/include/llvm/CodeGen/Passes.h
@@ -584,9 +584,6 @@ namespace llvm {
   /// or split the data to two <128 x i32>.
   FunctionPass *createX86LowerAMXTypePass();
 
-  /// The pass insert tile config intrinsics for AMX fast register allocation.
-  FunctionPass *createX86PreAMXConfigPass();
-
   /// The pass transforms amx intrinsics to scalar operation if the function has
   /// optnone attribute or it is O0.
   FunctionPass *createX86LowerAMXIntrinsicsPass();
diff --git a/llvm/lib/Target/X86/CMakeLists.txt b/llvm/lib/Target/X86/CMakeLists.txt
index c387d59ea981a52..0b7a98ad6341dde 100644
--- a/llvm/lib/Target/X86/CMakeLists.txt
+++ b/llvm/lib/Target/X86/CMakeLists.txt
@@ -33,7 +33,6 @@ set(sources
   X86DiscriminateMemOps.cpp
   X86LowerTileCopy.cpp
   X86LowerAMXType.cpp
-  X86PreAMXConfig.cpp
   X86LowerAMXIntrinsics.cpp
   X86TileConfig.cpp
   X86FastPreTileConfig.cpp
diff --git a/llvm/lib/Target/X86/X86.h b/llvm/lib/Target/X86/X86.h
index 3c5ca0788498032..485afbc1dfbc241 100644
--- a/llvm/lib/Target/X86/X86.h
+++ b/llvm/lib/Target/X86/X86.h
@@ -194,7 +194,6 @@ void initializeX86LowerAMXTypeLegacyPassPass(PassRegistry &);
 void initializeX86LowerTileCopyPass(PassRegistry &);
 void initializeX86OptimizeLEAPassPass(PassRegistry &);
 void initializeX86PartialReductionPass(PassRegistry &);
-void initializeX86PreAMXConfigPassPass(PassRegistry &);
 void initializeX86PreTileConfigPass(PassRegistry &);
 void initializeX86ReturnThunksPass(PassRegistry &);
 void initializeX86SpeculativeExecutionSideEffectSuppressionPass(PassRegistry &);
diff --git a/llvm/lib/Target/X86/X86PreAMXConfig.cpp b/llvm/lib/Target/X86/X86PreAMXConfig.cpp
deleted file mode 100644
index 7872a64061d438c..000000000000000
--- a/llvm/lib/Target/X86/X86PreAMXConfig.cpp
+++ /dev/null
@@ -1,415 +0,0 @@
-//===- Target/X86/X86PreAMXConfig.cpp - ------------------------*- C++ -*-===//
-//
-// 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
-//
-//===----------------------------------------------------------------------===//
-//
-/// Insert tilecfg for each area of key AMX intrinsic.
-/// All the key AMX intrinsic's tile operand must come from tileload. And the
-/// def tile of key AMX intrinsic must be tilestored.
-/// take tdpbssd for example:
-/// --------------------------------------------------------------------------
-/// %t1 = call x86_amx @llvm.x86.tileloadd64.internal(...)                key
-/// %t2 = call x86_amx @llvm.x86.tileloadd64.internal(...)                 |
-/// %t3 = call x86_amx @llvm.x86.tileloadd64.internal(...)                amx
-/// %td = tail call x86_amx @llvm.x86.tdpbssd.internal(t1, t2, t3)         |
-/// call void @llvm.x86.tilestored64.internal(... td)                     area
-/// --------------------------------------------------------------------------
-/// This pass will insert tilecfg before every key-amx-area, some like:
-/// --------------------------------------------------------------------------
-/// %cfgmem = alloca <16 x i32>, align 4                        * allocate mem
-/// store <16 x i32> zeroinitializer, <16 x i32>* %cfgmem       * zero init
-/// ...
-/// ... pre-config shape of %t1                                 *
-/// store volatile i8 %m, i8* %amx.tmm.0.shape.row, align 1     *
-/// store volatile i16 %k, i16* %amx.tmm.0.shape.col, align 2   * pre-config
-/// ...                                                         *
-/// ... pre-config shape of %t2                                 * shapes
-/// store volatile i8 %k, i8* %amx.tmm.1.shape.row, align 1     *
-/// store volatile i16 %n, i16* %amx.tmm.1.shape.col, align 2   *
-/// ...
-/// call void @llvm.x86.ldtilecfg(i8* %cfgmem)                  * tile config
-//
-//===----------------------------------------------------------------------===//
-//
-#include "X86.h"
-#include "llvm/ADT/SmallSet.h"
-#include "llvm/ADT/StringExtras.h"
-#include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/CodeGen/Passes.h"
-#include "llvm/CodeGen/TargetPassConfig.h"
-#include "llvm/CodeGen/ValueTypes.h"
-#include "llvm/IR/DataLayout.h"
-#include "llvm/IR/Function.h"
-#include "llvm/IR/IRBuilder.h"
-#include "llvm/IR/Instructions.h"
-#include "llvm/IR/IntrinsicInst.h"
-#include "llvm/IR/IntrinsicsX86.h"
-#include "llvm/IR/PatternMatch.h"
-#include "llvm/InitializePasses.h"
-#include "llvm/Pass.h"
-#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetMachine.h"
-
-using namespace llvm;
-using namespace PatternMatch;
-
-#define DEBUG_TYPE "pre-amx-config"
-
-static bool isAMXIntrinsic(IntrinsicInst *II) {
-  for (Value *Operand : II->operands())
-    if (Operand->getType()->isX86_AMXTy())
-      return true;
-  return II->getType()->isX86_AMXTy();
-}
-
-static bool isTileLoad(IntrinsicInst *II) {
-  return II->getIntrinsicID() == Intrinsic::x86_tileloadd64_internal ||
-         II->getIntrinsicID() == Intrinsic::x86_tileloaddt164_internal;
-}
-
-static bool isTileStore(IntrinsicInst *II) {
-  return II->getIntrinsicID() == Intrinsic::x86_tilestored64_internal;
-}
-
-#ifndef NDEBUG
-static bool onlyTileDef(IntrinsicInst *II) {
-  for (Value *Operand : II->operands())
-    if (Operand->getType()->isX86_AMXTy())
-      return false;
-  return II->getType()->isX86_AMXTy();
-}
-
-static bool brokenVolatile(Instruction *I) {
-  // Todo: it is weak to identify a normal call here.
-  if ((isa<CallInst>(I) && !isa<IntrinsicInst>(I)) || I->isTerminator())
-    return true;
-  return false;
-}
-#endif
-
-namespace {
-class X86PreAMXConfig {
-  using PosAndShapesMap = MapVector<Instruction *, SmallVector<Value *, 8>>;
-
-  Function &F;
-
-public:
-  X86PreAMXConfig(Function &Func) : F(Func) {}
-  bool preTileConfig();
-  void addTileConfig(Instruction *ModelStart, SmallVector<Value *, 8> &Shapes);
-  bool findConfigShapes(PosAndShapesMap &PosAndShapes);
-  bool getKeyAMXShapes(IntrinsicInst *KeyAMX, SmallVector<Value *, 8> &Shapes);
-  void preWriteTileCfg(Value *I8Ptr, IRBuilderBase &Builder,
-                       SmallVector<Value *, 8> &Shapes);
-  BasicBlock::iterator
-  getShapesAndConfigPosEnd(BasicBlock::iterator Iter,
-                           SmallVector<Value *, 8> &Shapes);
-  bool checkVolatileModel(SmallSet<Value *, 4> &Loads, IntrinsicInst *Store,
-                          IntrinsicInst *KeyAMX);
-};
-
-// Orderly write the shapes in tilecfg's mem. This maybe not right.
-// Because the first shape may not corresponding to the first tmm register,
-// so we need to handle at at X86FastTileConfig::materializeTileCfg()
-// after register allocation.
-// For example:
-// --------------------------------------------------------------------------
-// zeroinitialize tilecfg's mem (of ldtilecfg)
-// --------------------------------------------------------------------------
-// ... pre-config shape of %t1                                 *
-// %amx.tmm.0.shape.row = getelementptr i8, i8* %mem, i64 48   *
-// %amx.tmm.0.shape.col = getelementptr i16, i16* %mem, i64 16 *
-// store volatile i8 %m, i8* %amx.tmm.0.shape.row, align 1     *
-// store volatile i16 %k, i16* %amx.tmm.0.shape.col, align 2   * pre-config
-// ...                                                         *
-// ... pre-config shape of %t2                                 *
-// %amx.tmm.1.shape.row = getelementptr i8, i8* %mem, i64 49   *
-// %amx.tmm.1.shape.col = getelementptr i16, i16* %mem, i64 18 *
-// store volatile i8 %k, i8* %amx.tmm.1.shape.row, align 1     * shapes
-// store volatile i16 %n, i16* %amx.tmm.1.shape.col, align 2   *
-// ...                                                         *
-// ... pre-config shape of %t3                                 * of
-// %amx.tmm.2.shape.row = getelementptr i8, i8* %mem, i64 50   *
-// %amx.tmm.2.shape.col = getelementptr i16, i16* %mem, i64 20 *
-// store volatile i8 %m, i8* %amx.tmm.2.shape.row, align 1     *
-// store volatile i16 %n, i16* %amx.tmm.2.shape.col, align 2   *
-// ...                                                         * tiles
-// ... pre-config shape of %td                                 *
-// %amx.tmm.3.shape.row = getelementptr i8, i8* %mem, i64 51   *
-// %amx.tmm.3.shape.col = getelementptr i16, i16* %mem, i64 22 *
-// store volatile i8 %m, i8* %amx.tmm.3.shape.row, align 1     *
-// store volatile i16 %n, i16* %amx.tmm.3.shape.col, align 2   *
-// --------------------------------------------------------------------------
-// call void @llvm.x86.ldtilecfg(i8* %mem)                     * tile config
-// --------------------------------------------------------------------------
-// %t1 = call x86_amx @llvm.x86.tileloadd64.internal(m, k, ...)          key
-// %t2 = call x86_amx @llvm.x86.tileloadd64.internal(k, n, ...)
-// %t3 = call x86_amx @llvm.x86.tileloadd64.internal(m, n, ...)          amx
-// %td = tail call x86_amx @llvm.x86.tdpbssd.internal(m, n, k, t1, t2, t3)
-// call void @llvm.x86.tilestored64.internal(... td)                     area
-// --------------------------------------------------------------------------
-void X86PreAMXConfig::preWriteTileCfg(Value *I8Ptr, IRBuilderBase &Builder,
-                                      SmallVector<Value *, 8> &Shapes) {
-  LLVMContext &Ctx = Builder.getContext();
-  Type *I8Ty = Type::getInt8Ty(Ctx);
-  Type *I16Ty = Type::getInt16Ty(Ctx);
-
-  // TODO: Currently we defaultly set Palette = 1, it may be assigned to
-  // other value in the future.
-  Value *PaletteOffset = ConstantInt::get(Type::getInt64Ty(Ctx), 0);
-  Value *PaletteValue = ConstantInt::get(Type::getInt8Ty(Ctx), 1);
-  Value *PalettePos = Builder.CreateGEP(I8Ty, I8Ptr, PaletteOffset);
-  Builder.CreateStore(PaletteValue, PalettePos);
-
-  for (int I = 0, E = Shapes.size() / 2; I < E; I++) {
-    Value *RowOffset = ConstantInt::get(Type::getInt64Ty(Ctx), 48 + I);
-    Value *ColOffset = ConstantInt::get(Type::getInt64Ty(Ctx), 16 + I * 2);
-    const std::string ShapeName = "amx.tmm." + itostr(I);
-    Value *RowPos = Builder.CreateGEP(I8Ty, I8Ptr, RowOffset,
-                                      ShapeName + ".shape.row");
-    Value *ColPos = Builder.CreateGEP(I8Ty, I8Ptr, ColOffset);
-    ColPos = Builder.CreateBitCast(ColPos, PointerType::get(I16Ty, 0),
-                                   ShapeName + ".shape.col");
-    Value *Row = Shapes[I * 2];
-    Value *Col = Shapes[I * 2 + 1];
-    Row = Builder.CreateTrunc(Row, I8Ty);
-    Builder.CreateStore(Row, RowPos);
-    Builder.CreateStore(Col, ColPos);
-  }
-}
-
-void X86PreAMXConfig::addTileConfig(Instruction *ModelStart,
-                                    SmallVector<Value *, 8> &Shapes) {
-  Module *M = F.getParent();
-  IRBuilder<> Builder(ModelStart);
-  const DataLayout &DL = M->getDataLayout();
-  unsigned AddrSpace = DL.getAllocaAddrSpace();
-  LLVMContext &Ctx = Builder.getContext();
-  Type *V512Ty = VectorType::get(Builder.getInt32Ty(), 16, false);
-  Align Alignment = DL.getPrefTypeAlign(Type::getInt32Ty(Ctx));
-
-  AllocaInst *Addr =
-      new AllocaInst(V512Ty, AddrSpace, "", &F.getEntryBlock().front());
-  Addr->setAlignment(Alignment);
-  Value *I8Ptr = Builder.CreateBitCast(Addr, Builder.getInt8PtrTy());
-
-  Builder.CreateAlignedStore(Constant::getNullValue(V512Ty), Addr, Alignment);
-
-  preWriteTileCfg(I8Ptr, Builder, Shapes);
-
-  Builder.CreateIntrinsic(Intrinsic::x86_ldtilecfg_internal, std::nullopt,
-                          {I8Ptr});
-}
-
-// Todo: We may need to handle "more than one store" case in the future.
-bool X86PreAMXConfig::checkVolatileModel(SmallSet<Value *, 4> &Loads,
-                                         IntrinsicInst *Store,
-                                         IntrinsicInst *KeyAMX) {
-  Value *ST = Store->getOperand(4);
-
-  // Only has tileload and tilestore.
-  if (!KeyAMX)
-    return (Loads.size() == 1) && Loads.contains(ST);
-
-  // All Loads should be operands of KeyAMX.
-  // All tile operands of KeyAMX should come from Loads.
-  for (Value *Op : KeyAMX->operands()) {
-    if (Op->getType()->isX86_AMXTy())
-      if (!Loads.erase(Op))
-        return false;
-  }
-
-  // The def of KeyAMX should be stored into mem.
-  // Todo: is it key amx can be no def?
-  return Loads.empty() && (ST == cast<Value>(KeyAMX));
-}
-
-bool X86PreAMXConfig::getKeyAMXShapes(IntrinsicInst *KeyAMX,
-                                      SmallVector<Value *, 8> &Shapes) {
-  for (unsigned I = 0; I < KeyAMX->getNumOperands(); I++) {
-    Value *Op = KeyAMX->getOperand(I);
-    if (!Op->getType()->isX86_AMXTy())
-      continue;
-    IntrinsicInst *TileDef = dyn_cast<IntrinsicInst>(Op);
-    assert((TileDef && isTileLoad(TileDef)) &&
-           "All KeyAMX's tile definiation should comes from TileLoad!");
-    Shapes.push_back(TileDef->getOperand(0));
-    Shapes.push_back(TileDef->getOperand(1));
-  }
-  if (!isTileStore(KeyAMX)) {
-    Shapes.push_back(KeyAMX->getOperand(0));
-    Shapes.push_back(KeyAMX->getOperand(1));
-  }
-  return Shapes.size() != 0;
-}
-
-// Collect the shapes and skip the area of current key amx intrinsic.
-//
-// For example:
-// ...
-// --------------------------------------------------------------------------
-// %t1 = call x86_amx @llvm.x86.tileloadd64.internal(m, k, ...)  record (m,k)
-// %t2 = call x86_amx @llvm.x86.tileloadd64.internal(k, n, ...)  record (m,k)
-// %t3 = call x86_amx @llvm.x86.tileloadd64.internal(m, n, ...)  record (m,k)
-// %td = call x86_amx @llvm.x86.tdpbssd.internal(...t1, t2, t3)
-// call void @llvm.x86.tilestored64.internal(m, n,... td) <--PosEnd record (m,k)
-// --------------------------------------------------------------------------
-BasicBlock::iterator
-X86PreAMXConfig::getShapesAndConfigPosEnd(BasicBlock::iterator Iter,
-                                          SmallVector<Value *, 8> &Shapes) {
-  IntrinsicInst *KeyAMX = nullptr;
-  BasicBlock *BB = Iter->getParent();
-  BasicBlock::iterator PosEnd = BB->end();
-  SmallSet<Value *, 4> Loads;
-
-  // See TileStore as "Config Position End" and check volatile model.
-  for (auto I = Iter, E = BB->end(); I != E; ++I) {
-    assert(!brokenVolatile(&*I) && "Not reach tile store!");
-    IntrinsicInst *II = dyn_cast<IntrinsicInst>(&*I);
-    if (!II || !isAMXIntrinsic(II))
-      continue;
-
-    if (isTileLoad(II)) {
-      Loads.insert(II);
-    } else if (isTileStore(II)) {
-      if (!checkVolatileModel(Loads, II, KeyAMX))
-        report_fatal_error("Not Volatile AMX Model!");
-      PosEnd = I;
-      break;
-    } else {
-      assert(!KeyAMX && "Too many key amx intrinsic!");
-      KeyAMX = II;
-    }
-  }
-  assert(PosEnd != BB->end() && "Not find TileStore!");
-
-  // See KeyAMX as TileStore if only TileLoad and TileStore.
-  if (!KeyAMX)
-    KeyAMX = dyn_cast<IntrinsicInst>(&*PosEnd);
-
-  // Get Shapes in order.
-  assert(Shapes.empty() && "Shapes should be clean.");
-  getKeyAMXShapes(KeyAMX, Shapes);
-
-  return PosEnd;
-}
-
-// Record a key amx area's shapes with its position.
-// Use the first tileload as its position.
-// For example:
-// ...
-// --------------------------------------------------------------------------
-// %t1 = call x86_amx @llvm.x86.tileloadd64.internal(m, k, ...)   <--  pos
-// %t2 = call x86_amx @llvm.x86.tileloadd64.internal(k, n, ...)        /
-// %t3 = call x86_amx @llvm.x86.tileloadd64.internal(m, n, ...)     shapes:
-// %td = call x86_amx @llvm.x86.tdpbssd.internal(...t1, t2, t3)    (m,k)(k,n)
-// call void @llvm.x86.tilestored64.internal(m, n,... td)          (m,n)(m,n)
-// --------------------------------------------------------------------------
-bool X86PreAMXConfig::findConfigShapes(PosAndShapesMap &PosAndShapes) {
-  bool Find = false;
-  for (BasicBlock &BB : F) {
-    for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I) {
-      IntrinsicInst *II = dyn_cast<IntrinsicInst>(&*I);
-      if (!II)
-        continue;
-      if (!isAMXIntrinsic(II))
-        continue;
-      assert(onlyTileDef(II) && "Not volatile model for AMX at O0!");
-
-      I = getShapesAndConfigPosEnd(I, PosAndShapes[&*I]);
-      Find = true;
-    }
-  }
-  return Find;
-}
-
-// Insert ldtilecfg and preconfig the shapes for each area of key AMX intrinsic.
-// e.g. (key amx = tdpbssd)
-// --------------------------------------------------------------------------
-// %cfgmem = alloca <16 x i32>, align 4                        * allocate mem
-// store <16 x i32> zeroinitializer, <16 x i32>* %cfgmem       * zero init
-// ...
-// ... pre-config shape of %t1                                 *
-// store volatile i8 %m, i8* %amx.tmm.0.shape.row, align 1     *
-// store volatile i16 %k, i16* %amx.tmm.0.shape.col, align 2   * pre-config
-// ...                                                         *
-// ... pre-config shape of %t2                                 *
-// store volatile i8 %k, i8* %amx.tmm.1.shape.row, align 1     * shapes
-// store volatile i16 %n, i16* %amx.tmm.1.shape.col, align 2   *
-// ...                                                         *
-// ... pre-config shape of %t3                                 * of
-// store volatile i8 %m, i8* %amx.tmm.2.shape.row, align 1     *
-// store volatile i16 %n, i16* %amx.tmm.2.shape.col, align 2   *
-// ...                                                         * tiles
-// ... pre-config shape of %td                                 *
-// store volatile i8 %m, i8* %amx.tmm.3.shape.row, align 1     *
-// store volatile i16 %n, i16* %amx.tmm.3.shape.col, align 2   *
-//
-// call void @llvm.x86.ldtilecfg(i8* %cfgmem)                  * pre-config
-// --------------------------------------------------------------------------
-// %t1 = call x86_amx @llvm.x86.tileloadd64.internal(m, k, ...)          key
-// %t2 = call x86_amx @llvm.x86.tileloadd64.internal(k, n, ...)
-// %t3 = call x86_amx @llvm.x86.tileloadd64.internal(m, n, ...)          amx
-// %td = tail call x86_amx @llvm.x86.tdpbssd.internal(m, n, k, t1, t2, t3)
-// call void @llvm.x86.tilestored64.internal(... td)                     area
-// --------------------------------------------------------------------------
-bool X86PreAMXConfig::preTileConfig() {
-  PosAndShapesMap PosAndShapes;
-  bool NeedCfg = findConfigShapes(PosAndShapes);
-  if (!NeedCfg)
-    return false;
-  for (auto &IPAndShapes : PosAndShapes)
-    addTileConfig(IPAndShapes.first, IPAndShapes.second);
-
-  return true;
-}
-} // anonymous namespace
-
-namespace {
-
-class X86PreAMXConfigPass : public FunctionPass {
-public:
-  static char ID;
-
-  X86PreAMXConfigPass() : FunctionPass(ID) {
-    initializeX86PreAMXConfigPassPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override {
-    TargetMachine *TM = &getAnalysis<TargetPassConfig>().getTM<TargetMachine>();
-    bool C = false;
-
-    // Prepare for fast register allocation at O0.
-    if (TM->getOptLevel() == CodeGenOptLevel::None) {
-
-      // We pre-config each key AMX intrinsic at O0.
-      // In theory, one tile config can cover several AMX intrinsics, but
-      // it is very diffcult to classify the tile shapes at O0. So here we
-      // let thing be easy, pre-config every key AMX intrinsic.
-      X86PreAMXConfig PCFG(F);
-      C = PCFG.preTileConfig();
-    }
-
-    return C;
-  }
-
-  void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
-    AU.addRequired<TargetPassConfig>();
-  }
-};
-
-} // anonymous namespace
-
-static const char PassName[] = "Pre AMX Tile Config";
-char X86PreAMXConfigPass::ID = 0;
-INITIALIZE_PASS_BEGIN(X86PreAMXConfigPass, DEBUG_TYPE, PassName, false, fals...
[truncated]

[kazutakahirata]

LGTM. Thanks!