[clang] [llvm] [HLSL] Adding Flatten and Branch if attributes (PR #116331)

via llvm-commits llvm-commits at lists.llvm.org
Fri Nov 15 11:29:45 PST 2024


https://github.com/joaosaffran updated https://github.com/llvm/llvm-project/pull/116331

>From 3c792216f88e87b69b3ea7415c2fd74b7f5d7469 Mon Sep 17 00:00:00 2001
From: Joao Saffran <jderezende at microsoft.com>
Date: Fri, 25 Oct 2024 17:48:41 +0000
Subject: [PATCH 1/6] adding comments

---
 clang/include/clang/Basic/Attr.td     | 10 ++++++++++
 clang/lib/CodeGen/CGStmt.cpp          |  2 ++
 clang/lib/CodeGen/CodeGenFunction.cpp |  2 ++
 clang/lib/Sema/SemaStmtAttr.cpp       |  8 ++++++++
 4 files changed, 22 insertions(+)

diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index b3c357ec906a23..6d3e07ce83100b 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -4302,6 +4302,16 @@ def HLSLLoopHint: StmtAttr {
   let Documentation = [HLSLLoopHintDocs, HLSLUnrollHintDocs];
 }
 
+def HLSLBranchHint: StmtAttr {
+  /// [branch]
+  /// [flatten]
+  let Spellings = [Microsoft<"branch">, Microsoft<"flatten">];
+  let Subjects = SubjectList<[IfStmt],
+                              ErrorDiag, "'if' statements">;
+  let LangOpts = [HLSL];
+  let Documentation = [InternalOnly];
+}
+
 def CapturedRecord : InheritableAttr {
   // This attribute has no spellings as it is only ever created implicitly.
   let Spellings = [];
diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 698baf853507f4..7b01dc84b55365 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -761,6 +761,7 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
         Builder.CreateAssumption(AssumptionVal);
       }
     } break;
+    // [jderezende] TODO: Add HLSLBranchHint, to mark if flatten/branch is present.
     }
   }
   SaveAndRestore save_nomerge(InNoMergeAttributedStmt, nomerge);
@@ -768,6 +769,7 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
   SaveAndRestore save_alwaysinline(InAlwaysInlineAttributedStmt, alwaysinline);
   SaveAndRestore save_noconvergent(InNoConvergentAttributedStmt, noconvergent);
   SaveAndRestore save_musttail(MustTailCall, musttail);
+  // [jderezende] TODO: Save HLSLBranchHint information
   EmitStmt(S.getSubStmt(), S.getAttrs());
 }
 
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 6ead45793742d6..fc4fde81984d64 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -43,6 +43,7 @@
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/Support/CRC.h"
 #include "llvm/Support/xxhash.h"
@@ -2076,6 +2077,7 @@ void CodeGenFunction::EmitBranchOnBoolExpr(
     Weights = createProfileWeights(TrueCount, CurrentCount - TrueCount);
   }
 
+  // [jderezende] TODO: Emit branch metadata marking it as flatten/branch, if exists.
   Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable);
 }
 
diff --git a/clang/lib/Sema/SemaStmtAttr.cpp b/clang/lib/Sema/SemaStmtAttr.cpp
index f801455596fe6f..68323092cb564d 100644
--- a/clang/lib/Sema/SemaStmtAttr.cpp
+++ b/clang/lib/Sema/SemaStmtAttr.cpp
@@ -623,6 +623,12 @@ static Attr *handleHLSLLoopHintAttr(Sema &S, Stmt *St, const ParsedAttr &A,
   return ::new (S.Context) HLSLLoopHintAttr(S.Context, A, UnrollFactor);
 }
 
+static Attr *handleHLSLBranchHint(Sema &S, Stmt *St, const ParsedAttr &A,
+                                    SourceRange Range) {
+
+  return ::new (S.Context) HLSLBranchHintAttr(S.Context, A);
+}
+
 static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
                                   SourceRange Range) {
   if (A.isInvalid() || A.getKind() == ParsedAttr::IgnoredAttribute)
@@ -659,6 +665,8 @@ static Attr *ProcessStmtAttribute(Sema &S, Stmt *St, const ParsedAttr &A,
     return handleLoopHintAttr(S, St, A, Range);
   case ParsedAttr::AT_HLSLLoopHint:
     return handleHLSLLoopHintAttr(S, St, A, Range);
+  case ParsedAttr::AT_HLSLBranchHint:
+    return handleHLSLBranchHint(S, St, A, Range);
   case ParsedAttr::AT_OpenCLUnrollHint:
     return handleOpenCLUnrollHint(S, St, A, Range);
   case ParsedAttr::AT_Suppress:

>From f48e382b7ff396fbf1b2ce7dcea9529a06fa9b12 Mon Sep 17 00:00:00 2001
From: Joao Saffran <jderezende at microsoft.com>
Date: Mon, 28 Oct 2024 23:58:10 +0000
Subject: [PATCH 2/6] continue exploration

---
 llvm/include/llvm/IR/FixedMetadataKinds.def | 3 +++
 llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp | 1 +
 2 files changed, 4 insertions(+)

diff --git a/llvm/include/llvm/IR/FixedMetadataKinds.def b/llvm/include/llvm/IR/FixedMetadataKinds.def
index df572e8791e13b..02a986d42f1933 100644
--- a/llvm/include/llvm/IR/FixedMetadataKinds.def
+++ b/llvm/include/llvm/IR/FixedMetadataKinds.def
@@ -53,3 +53,6 @@ LLVM_FIXED_MD_KIND(MD_DIAssignID, "DIAssignID", 38)
 LLVM_FIXED_MD_KIND(MD_coro_outside_frame, "coro.outside.frame", 39)
 LLVM_FIXED_MD_KIND(MD_mmra, "mmra", 40)
 LLVM_FIXED_MD_KIND(MD_noalias_addrspace, "noalias.addrspace", 41)
+// [jderezende] TODO: this will likelly be placed somewhere else,
+// so we don't mix dxil/hlsl/spirv and clang metadata
+LLVM_FIXED_MD_KIND(MD_dxil_controlflow_hints, "dx.controlflow.hints", 42)
diff --git a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
index 13e05b67927518..bff8cc1cfc5821 100644
--- a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
@@ -645,6 +645,7 @@ class SPIRVStructurizer : public FunctionPass {
 
       auto MergeAddress = BlockAddress::get(BB.getParent(), &BB);
       SmallVector<Value *, 1> Args = {MergeAddress};
+      // [jderezende] TODO: Pass metadata from Header->getTerminator() to modify the intrinsic
       Builder.CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
 
       Modified = true;

>From feb9d2dfc020e27a69637774f896d16f74e20625 Mon Sep 17 00:00:00 2001
From: Joao Saffran <jderezende at microsoft.com>
Date: Thu, 14 Nov 2024 02:13:12 +0000
Subject: [PATCH 3/6] adding attribute lowering

---
 clang/lib/CodeGen/CGStmt.cpp                  | 10 ++++--
 clang/lib/CodeGen/CodeGenFunction.cpp         | 15 +++++++-
 clang/lib/CodeGen/CodeGenFunction.h           |  7 ++++
 clang/lib/CodeGen/CodeGenPGO.cpp              | 17 ++++++++++
 llvm/include/llvm/IR/IRBuilder.h              | 11 ++++--
 llvm/include/llvm/IR/IntrinsicsSPIRV.td       |  2 +-
 llvm/include/llvm/IR/ProfDataUtils.h          |  7 ++++
 llvm/lib/IR/ProfDataUtils.cpp                 |  7 ++++
 .../Target/SPIRV/SPIRVInstructionSelector.cpp | 34 +++++++++++++++----
 llvm/lib/Target/SPIRV/SPIRVMetadata.cpp       |  2 +-
 llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp   | 14 ++++++--
 11 files changed, 109 insertions(+), 17 deletions(-)

diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 7b01dc84b55365..2f95ceb297f7d8 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -16,6 +16,7 @@
 #include "CodeGenModule.h"
 #include "TargetInfo.h"
 #include "clang/AST/Attr.h"
+#include "clang/AST/Attrs.inc"
 #include "clang/AST/Expr.h"
 #include "clang/AST/Stmt.h"
 #include "clang/AST/StmtVisitor.h"
@@ -730,6 +731,8 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
   bool noinline = false;
   bool alwaysinline = false;
   bool noconvergent = false;
+  HLSLBranchHintAttr::Spelling flattenOrBranch =
+      HLSLBranchHintAttr::SpellingNotCalculated;
   const CallExpr *musttail = nullptr;
 
   for (const auto *A : S.getAttrs()) {
@@ -761,7 +764,9 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
         Builder.CreateAssumption(AssumptionVal);
       }
     } break;
-    // [jderezende] TODO: Add HLSLBranchHint, to mark if flatten/branch is present.
+    case attr::HLSLBranchHint: {
+      flattenOrBranch = cast<HLSLBranchHintAttr>(A)->getSemanticSpelling();
+    } break;
     }
   }
   SaveAndRestore save_nomerge(InNoMergeAttributedStmt, nomerge);
@@ -769,7 +774,8 @@ void CodeGenFunction::EmitAttributedStmt(const AttributedStmt &S) {
   SaveAndRestore save_alwaysinline(InAlwaysInlineAttributedStmt, alwaysinline);
   SaveAndRestore save_noconvergent(InNoConvergentAttributedStmt, noconvergent);
   SaveAndRestore save_musttail(MustTailCall, musttail);
-  // [jderezende] TODO: Save HLSLBranchHint information
+  SaveAndRestore save_flattenOrBranch(HLSLBranchHintAttributedSpelling,
+                                      flattenOrBranch);
   EmitStmt(S.getSubStmt(), S.getAttrs());
 }
 
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index fc4fde81984d64..a799e017f46c5e 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -24,6 +24,7 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTLambda.h"
 #include "clang/AST/Attr.h"
+#include "clang/AST/Attrs.inc"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/Expr.h"
@@ -2053,6 +2054,7 @@ void CodeGenFunction::EmitBranchOnBoolExpr(
 
   llvm::MDNode *Weights = nullptr;
   llvm::MDNode *Unpredictable = nullptr;
+  llvm::MDNode *ControlFlowHint = nullptr;
 
   // If the branch has a condition wrapped by __builtin_unpredictable,
   // create metadata that specifies that the branch is unpredictable.
@@ -2077,8 +2079,19 @@ void CodeGenFunction::EmitBranchOnBoolExpr(
     Weights = createProfileWeights(TrueCount, CurrentCount - TrueCount);
   }
 
+  switch (HLSLBranchHintAttributedSpelling) {
+
+  case HLSLBranchHintAttr::Microsoft_branch:
+  case HLSLBranchHintAttr::Microsoft_flatten:
+    ControlFlowHint = createControlFlowHint(HLSLBranchHintAttributedSpelling);
+    break;
+  case HLSLBranchHintAttr::SpellingNotCalculated:
+    break;
+  }
+
   // [jderezende] TODO: Emit branch metadata marking it as flatten/branch, if exists.
-  Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable);
+  Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable,
+                       ControlFlowHint);
 }
 
 /// ErrorUnsupported - Print out an error that codegen doesn't support the
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index fcc1013d7361ec..f1001dc21e5e5d 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -21,6 +21,7 @@
 #include "CodeGenPGO.h"
 #include "EHScopeStack.h"
 #include "VarBypassDetector.h"
+#include "clang/AST/Attrs.inc"
 #include "clang/AST/CharUnits.h"
 #include "clang/AST/CurrentSourceLocExprScope.h"
 #include "clang/AST/ExprCXX.h"
@@ -615,6 +616,10 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// True if the current statement has noconvergent attribute.
   bool InNoConvergentAttributedStmt = false;
 
+  /// HLSL Branch attribute.
+  HLSLBranchHintAttr::Spelling HLSLBranchHintAttributedSpelling =
+      HLSLBranchHintAttr::SpellingNotCalculated;
+
   // The CallExpr within the current statement that the musttail attribute
   // applies to.  nullptr if there is no 'musttail' on the current statement.
   const CallExpr *MustTailCall = nullptr;
@@ -1612,6 +1617,8 @@ class CodeGenFunction : public CodeGenTypeCache {
   /// Bitmap used by MC/DC to track condition outcomes of a boolean expression.
   Address MCDCCondBitmapAddr = Address::invalid();
 
+  llvm::MDNode *createControlFlowHint(HLSLBranchHintAttr::Spelling S) const;
+
   /// Calculate branch weights appropriate for PGO data
   llvm::MDNode *createProfileWeights(uint64_t TrueCount,
                                      uint64_t FalseCount) const;
diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index 820bb521ccf850..d8d72f91f28708 100644
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -13,10 +13,14 @@
 #include "CodeGenPGO.h"
 #include "CodeGenFunction.h"
 #include "CoverageMappingGen.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/AST/Attrs.inc"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/StmtVisitor.h"
+#include "llvm/ADT/ArrayRef.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/FileSystem.h"
@@ -1451,6 +1455,19 @@ static uint32_t scaleBranchWeight(uint64_t Weight, uint64_t Scale) {
   return Scaled;
 }
 
+llvm::MDNode *
+CodeGenFunction::createControlFlowHint(HLSLBranchHintAttr::Spelling S) const {
+  llvm::MDBuilder MDHelper(CGM.getLLVMContext());
+
+  SmallVector<llvm::Metadata *, 2> Vals(llvm::ArrayRef<llvm::Metadata *>{
+      MDHelper.createString("dx.controlflow.hints"),
+      S == HLSLBranchHintAttr::Spelling::Microsoft_branch
+          ? MDHelper.createConstant(llvm::ConstantInt::get(Int32Ty, 1))
+          : MDHelper.createConstant(llvm::ConstantInt::get(Int32Ty, 2))});
+
+  return llvm::MDNode::get(CGM.getLLVMContext(), Vals);
+}
+
 llvm::MDNode *CodeGenFunction::createProfileWeights(uint64_t TrueCount,
                                                     uint64_t FalseCount) const {
   // Check for empty weights.
diff --git a/llvm/include/llvm/IR/IRBuilder.h b/llvm/include/llvm/IR/IRBuilder.h
index 23fd8350a29b3d..215d3362bd4f6c 100644
--- a/llvm/include/llvm/IR/IRBuilder.h
+++ b/llvm/include/llvm/IR/IRBuilder.h
@@ -1101,11 +1101,14 @@ class IRBuilderBase {
   /// instruction.
   /// \returns The annotated instruction.
   template <typename InstTy>
-  InstTy *addBranchMetadata(InstTy *I, MDNode *Weights, MDNode *Unpredictable) {
+  InstTy *addBranchMetadata(InstTy *I, MDNode *Weights, MDNode *Unpredictable,
+                            MDNode *ControlFlowHint = nullptr) {
     if (Weights)
       I->setMetadata(LLVMContext::MD_prof, Weights);
     if (Unpredictable)
       I->setMetadata(LLVMContext::MD_unpredictable, Unpredictable);
+    if (ControlFlowHint)
+      I->setMetadata(LLVMContext::MD_dxil_controlflow_hints, ControlFlowHint);
     return I;
   }
 
@@ -1143,9 +1146,11 @@ class IRBuilderBase {
   /// instruction.
   BranchInst *CreateCondBr(Value *Cond, BasicBlock *True, BasicBlock *False,
                            MDNode *BranchWeights = nullptr,
-                           MDNode *Unpredictable = nullptr) {
+                           MDNode *Unpredictable = nullptr,
+                           MDNode *ControlFlowHint = nullptr) {
     return Insert(addBranchMetadata(BranchInst::Create(True, False, Cond),
-                                    BranchWeights, Unpredictable));
+                                    BranchWeights, Unpredictable,
+                                    ControlFlowHint));
   }
 
   /// Create a conditional 'br Cond, TrueDest, FalseDest'
diff --git a/llvm/include/llvm/IR/IntrinsicsSPIRV.td b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
index f29eb7ee22b2d2..4a5f744c74d9be 100644
--- a/llvm/include/llvm/IR/IntrinsicsSPIRV.td
+++ b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
@@ -33,7 +33,7 @@ let TargetPrefix = "spv" in {
   def int_spv_ptrcast : Intrinsic<[llvm_any_ty], [llvm_any_ty, llvm_metadata_ty, llvm_i32_ty], [ImmArg<ArgIndex<2>>]>;
   def int_spv_switch : Intrinsic<[], [llvm_any_ty, llvm_vararg_ty]>;
   def int_spv_loop_merge : Intrinsic<[], [llvm_vararg_ty]>;
-  def int_spv_selection_merge : Intrinsic<[], [llvm_vararg_ty]>;
+  def int_spv_selection_merge : Intrinsic<[], [llvm_metadata_ty, llvm_vararg_ty]>;
   def int_spv_cmpxchg : Intrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_vararg_ty]>;
   def int_spv_unreachable : Intrinsic<[], []>;
   def int_spv_alloca : Intrinsic<[llvm_any_ty], []>;
diff --git a/llvm/include/llvm/IR/ProfDataUtils.h b/llvm/include/llvm/IR/ProfDataUtils.h
index 0bea517df832e3..49f7da480f928d 100644
--- a/llvm/include/llvm/IR/ProfDataUtils.h
+++ b/llvm/include/llvm/IR/ProfDataUtils.h
@@ -48,6 +48,13 @@ bool hasValidBranchWeightMD(const Instruction &I);
 /// Nullptr otherwise.
 MDNode *getBranchWeightMDNode(const Instruction &I);
 
+/// Get the branching metadata information
+///
+/// \param I The Instruction to get the weights from.
+/// \returns A pointer to I's branch weights metadata node, if it exists.
+/// Nullptr otherwise.
+MDNode *getDxBranchHint(const Instruction &I);
+
 /// Get the valid branch weights metadata node
 ///
 /// \param I The Instruction to get the weights from.
diff --git a/llvm/lib/IR/ProfDataUtils.cpp b/llvm/lib/IR/ProfDataUtils.cpp
index 5441228b3291ee..47a5059017a48f 100644
--- a/llvm/lib/IR/ProfDataUtils.cpp
+++ b/llvm/lib/IR/ProfDataUtils.cpp
@@ -150,6 +150,13 @@ MDNode *getBranchWeightMDNode(const Instruction &I) {
   return ProfileData;
 }
 
+MDNode *getDxBranchHint(const Instruction &I) {
+  MDNode *Node = I.getMetadata(LLVMContext::MD_dxil_controlflow_hints);
+  if (!isTargetMD(Node, "dx.controlflow.hints", 2))
+    return nullptr;
+  return Node;
+}
+
 MDNode *getValidBranchWeightMDNode(const Instruction &I) {
   auto *ProfileData = getBranchWeightMDNode(I);
   if (ProfileData && getNumBranchWeights(*ProfileData) == I.getNumSuccessors())
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 8a8835e0269200..f3f78fb4f2bdbb 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -32,6 +32,7 @@
 #include "llvm/CodeGen/Register.h"
 #include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/IR/IntrinsicsSPIRV.h"
+#include "llvm/IR/Metadata.h"
 #include "llvm/Support/Debug.h"
 
 #define DEBUG_TYPE "spirv-isel"
@@ -2694,12 +2695,8 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
     }
     return MIB.constrainAllUses(TII, TRI, RBI);
   }
-  case Intrinsic::spv_loop_merge:
-  case Intrinsic::spv_selection_merge: {
-    const auto Opcode = IID == Intrinsic::spv_selection_merge
-                            ? SPIRV::OpSelectionMerge
-                            : SPIRV::OpLoopMerge;
-    auto MIB = BuildMI(BB, I, I.getDebugLoc(), TII.get(Opcode));
+  case Intrinsic::spv_loop_merge: {
+    auto MIB = BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpLoopMerge));
     for (unsigned i = 1; i < I.getNumExplicitOperands(); ++i) {
       assert(I.getOperand(i).isMBB());
       MIB.addMBB(I.getOperand(i).getMBB());
@@ -2707,6 +2704,31 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
     MIB.addImm(SPIRV::SelectionControl::None);
     return MIB.constrainAllUses(TII, TRI, RBI);
   }
+  case Intrinsic::spv_selection_merge: {
+
+    auto SelectionControl = SPIRV::SelectionControl::None;
+    const MDNode *MDOp = I.getOperand(1).getMetadata();
+    if (MDOp->getNumOperands() > 0) {
+      ConstantInt *BranchHint =
+          mdconst::extract<ConstantInt>(MDOp->getOperand(1));
+
+      if (BranchHint->equalsInt(2))
+        SelectionControl = SPIRV::SelectionControl::Flatten;
+      else if (BranchHint->equalsInt(1))
+        SelectionControl = SPIRV::SelectionControl::DontFlatten;
+      else
+        llvm_unreachable("Invalid value for SelectionControl");
+    }
+
+    auto MIB =
+        BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpSelectionMerge));
+    for (unsigned i = 2; i < I.getNumExplicitOperands(); ++i) {
+      assert(I.getOperand(i).isMBB());
+      MIB.addMBB(I.getOperand(i).getMBB());
+    }
+    MIB.addImm(SelectionControl);
+    return MIB.constrainAllUses(TII, TRI, RBI);
+  }
   case Intrinsic::spv_cmpxchg:
     return selectAtomicCmpXchg(ResVReg, ResType, I);
   case Intrinsic::spv_unreachable:
diff --git a/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp b/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp
index 3800aac70df327..7d5617919df87c 100644
--- a/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "SPIRVMetadata.h"
+#include "llvm/IR/Metadata.h"
 
 using namespace llvm;
 
@@ -81,5 +82,4 @@ MDString *getOCLKernelArgTypeQual(const Function &F, unsigned ArgIdx) {
       "Kernel attributes are attached/belong only to OpenCL kernel functions");
   return getOCLKernelArgAttribute(F, ArgIdx, "kernel_arg_type_qual");
 }
-
 } // namespace llvm
diff --git a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
index bff8cc1cfc5821..6fed0b81bf61e7 100644
--- a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
@@ -13,6 +13,7 @@
 #include "SPIRVSubtarget.h"
 #include "SPIRVTargetMachine.h"
 #include "SPIRVUtils.h"
+#include "llvm-c/Core.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -23,6 +24,8 @@
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IntrinsicsSPIRV.h"
+#include "llvm/IR/Metadata.h"
+#include "llvm/IR/ProfDataUtils.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/LoopSimplify.h"
@@ -95,7 +98,7 @@ BasicBlock *getDesignatedMergeBlock(Instruction *I) {
       II->getIntrinsicID() != Intrinsic::spv_selection_merge)
     return nullptr;
 
-  BlockAddress *BA = cast<BlockAddress>(II->getOperand(0));
+  BlockAddress *BA = cast<BlockAddress>(II->getOperand(1));
   return BA->getBasicBlock();
 }
 
@@ -644,8 +647,13 @@ class SPIRVStructurizer : public FunctionPass {
       Builder.SetInsertPoint(Header->getTerminator());
 
       auto MergeAddress = BlockAddress::get(BB.getParent(), &BB);
-      SmallVector<Value *, 1> Args = {MergeAddress};
-      // [jderezende] TODO: Pass metadata from Header->getTerminator() to modify the intrinsic
+
+      MDNode *BranchMdNode = getDxBranchHint(*Header->getTerminator());
+      Value *MDNodeValue =
+          MetadataAsValue::get(Builder.getContext(), BranchMdNode);
+
+      SmallVector<Value *, 2> Args = {MDNodeValue, MergeAddress};
+
       Builder.CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
 
       Modified = true;

>From 9beb5f17bfefcea148c1954b1b7bd458c4372389 Mon Sep 17 00:00:00 2001
From: Joao Saffran <jderezende at microsoft.com>
Date: Fri, 15 Nov 2024 00:08:26 +0000
Subject: [PATCH 4/6] adding tests

---
 clang/lib/CodeGen/CGStmt.cpp                  |  1 -
 clang/lib/CodeGen/CodeGenFunction.cpp         |  3 -
 clang/lib/CodeGen/CodeGenFunction.h           |  1 -
 clang/lib/CodeGen/CodeGenPGO.cpp              |  4 -
 clang/test/AST/HLSL/HLSLBranchHint.hlsl       | 43 +++++++++
 clang/test/CodeGenHLSL/HLSLBranchHint.hlsl    | 48 ++++++++++
 llvm/include/llvm/IR/FixedMetadataKinds.def   |  2 +-
 .../Target/SPIRV/SPIRVInstructionSelector.cpp |  1 -
 llvm/lib/Target/SPIRV/SPIRVMetadata.cpp       |  2 +-
 llvm/test/CodeGen/DirectX/HLSLBranchHint.ll   | 95 +++++++++++++++++++
 llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll     | 91 ++++++++++++++++++
 11 files changed, 279 insertions(+), 12 deletions(-)
 create mode 100644 clang/test/AST/HLSL/HLSLBranchHint.hlsl
 create mode 100644 clang/test/CodeGenHLSL/HLSLBranchHint.hlsl
 create mode 100644 llvm/test/CodeGen/DirectX/HLSLBranchHint.ll
 create mode 100644 llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll

diff --git a/clang/lib/CodeGen/CGStmt.cpp b/clang/lib/CodeGen/CGStmt.cpp
index 2f95ceb297f7d8..bf82e50c8b59e0 100644
--- a/clang/lib/CodeGen/CGStmt.cpp
+++ b/clang/lib/CodeGen/CGStmt.cpp
@@ -16,7 +16,6 @@
 #include "CodeGenModule.h"
 #include "TargetInfo.h"
 #include "clang/AST/Attr.h"
-#include "clang/AST/Attrs.inc"
 #include "clang/AST/Expr.h"
 #include "clang/AST/Stmt.h"
 #include "clang/AST/StmtVisitor.h"
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index a799e017f46c5e..a790d1fde0e104 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -24,7 +24,6 @@
 #include "clang/AST/ASTContext.h"
 #include "clang/AST/ASTLambda.h"
 #include "clang/AST/Attr.h"
-#include "clang/AST/Attrs.inc"
 #include "clang/AST/Decl.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/Expr.h"
@@ -44,7 +43,6 @@
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
-#include "llvm/IR/Metadata.h"
 #include "llvm/IR/Operator.h"
 #include "llvm/Support/CRC.h"
 #include "llvm/Support/xxhash.h"
@@ -2089,7 +2087,6 @@ void CodeGenFunction::EmitBranchOnBoolExpr(
     break;
   }
 
-  // [jderezende] TODO: Emit branch metadata marking it as flatten/branch, if exists.
   Builder.CreateCondBr(CondV, TrueBlock, FalseBlock, Weights, Unpredictable,
                        ControlFlowHint);
 }
diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h
index f1001dc21e5e5d..d3f1af6f5a5ce9 100644
--- a/clang/lib/CodeGen/CodeGenFunction.h
+++ b/clang/lib/CodeGen/CodeGenFunction.h
@@ -21,7 +21,6 @@
 #include "CodeGenPGO.h"
 #include "EHScopeStack.h"
 #include "VarBypassDetector.h"
-#include "clang/AST/Attrs.inc"
 #include "clang/AST/CharUnits.h"
 #include "clang/AST/CurrentSourceLocExprScope.h"
 #include "clang/AST/ExprCXX.h"
diff --git a/clang/lib/CodeGen/CodeGenPGO.cpp b/clang/lib/CodeGen/CodeGenPGO.cpp
index d8d72f91f28708..ff3826ca6da854 100644
--- a/clang/lib/CodeGen/CodeGenPGO.cpp
+++ b/clang/lib/CodeGen/CodeGenPGO.cpp
@@ -13,14 +13,10 @@
 #include "CodeGenPGO.h"
 #include "CodeGenFunction.h"
 #include "CoverageMappingGen.h"
-#include "clang/AST/ASTContext.h"
-#include "clang/AST/Attrs.inc"
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/StmtVisitor.h"
-#include "llvm/ADT/ArrayRef.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/MDBuilder.h"
-#include "llvm/IR/Metadata.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Endian.h"
 #include "llvm/Support/FileSystem.h"
diff --git a/clang/test/AST/HLSL/HLSLBranchHint.hlsl b/clang/test/AST/HLSL/HLSLBranchHint.hlsl
new file mode 100644
index 00000000000000..907d6c5ff580c0
--- /dev/null
+++ b/clang/test/AST/HLSL/HLSLBranchHint.hlsl
@@ -0,0 +1,43 @@
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-compute -ast-dump %s | FileCheck %s
+
+// CHECK: FunctionDecl 0x{{[0-9A-Fa-f]+}} <{{.*}}> {{.*}} used branch 'int (int)'
+// CHECK: AttributedStmt 0x{{[0-9A-Fa-f]+}} <<invalid sloc>
+// CHECK-NEXT: HLSLBranchHintAttr 0x{{[0-9A-Fa-f]+}} <{{.*}}> branch
+export int branch(int X){
+    int resp;
+    [branch] if (X > 0) {
+        resp = -X;
+    } else {
+        resp = X * 2;
+    }
+
+    return resp;
+}
+
+// CHECK: FunctionDecl 0x{{[0-9A-Fa-f]+}} <{{.*}}> {{.*}} used flatten 'int (int)'
+// CHECK: AttributedStmt 0x{{[0-9A-Fa-f]+}} <<invalid sloc>
+// CHECK-NEXT: HLSLBranchHintAttr 0x{{[0-9A-Fa-f]+}} <{{.*}}> flatten
+export int flatten(int X){
+    int resp;
+    [flatten] if (X > 0) {
+        resp = -X;
+    } else {
+        resp = X * 2;
+    }
+
+    return resp;
+}
+
+// CHECK: FunctionDecl 0x{{[0-9A-Fa-f]+}} <{{.*}}> {{.*}} used no_attr 'int (int)'
+// CHECK-NO: AttributedStmt 0x{{[0-9A-Fa-f]+}} <<invalid sloc>
+// CHECK-NO: HLSLBranchHintAttr
+export int no_attr(int X){
+    int resp;
+    if (X > 0) {
+        resp = -X;
+    } else {
+        resp = X * 2;
+    }
+
+    return resp;
+}
diff --git a/clang/test/CodeGenHLSL/HLSLBranchHint.hlsl b/clang/test/CodeGenHLSL/HLSLBranchHint.hlsl
new file mode 100644
index 00000000000000..11b14b1ec43175
--- /dev/null
+++ b/clang/test/CodeGenHLSL/HLSLBranchHint.hlsl
@@ -0,0 +1,48 @@
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple dxil-pc-shadermodel6.3-library %s -fnative-half-type -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple spirv-vulkan-library %s -fnative-half-type -emit-llvm -o - | FileCheck %s
+
+// CHECK: define {{.*}} i32 {{.*}}test_branch{{.*}}(i32 {{.*}} [[VALD:%.*]])
+// CHECK: [[PARAM:%.*]] = load i32, ptr [[VALD]].addr, align 4
+// CHECK: [[CMP:%.*]] = icmp sgt i32 [[PARAM]], 0
+// CHECK: br i1 [[CMP]], label %if.then, label %if.else, !dx.controlflow.hints [[HINT_BRANCH:![0-9]+]]
+export int test_branch(int X){
+    int resp;
+    [branch] if (X > 0) {
+        resp = -X;
+    } else {
+        resp = X * 2;
+    }
+
+    return resp;
+}
+
+// CHECK: define {{.*}} i32 {{.*}}test_flatten{{.*}}(i32 {{.*}} [[VALD:%.*]])
+// CHECK: [[PARAM:%.*]] = load i32, ptr [[VALD]].addr, align 4
+// CHECK: [[CMP:%.*]] = icmp sgt i32 [[PARAM]], 0
+// CHECK: br i1 [[CMP]], label %if.then, label %if.else, !dx.controlflow.hints [[HINT_FLATTEN:![0-9]+]]
+export int test_flatten(int X){
+    int resp;
+    [flatten] if (X > 0) {
+        resp = -X;
+    } else {
+        resp = X * 2;
+    }
+
+    return resp;
+}
+
+// CHECK: define {{.*}} i32 {{.*}}test_no_attr{{.*}}(i32 {{.*}} [[VALD:%.*]])
+// CHECK-NO: !dx.controlflow.hints
+export int test_no_attr(int X){
+    int resp;
+    if (X > 0) {
+        resp = -X;
+    } else {
+        resp = X * 2;
+    }
+
+    return resp;
+}
+
+//CHECK: [[HINT_BRANCH]] = !{!"dx.controlflow.hints", i32 1}
+//CHECK: [[HINT_FLATTEN]] = !{!"dx.controlflow.hints", i32 2}
diff --git a/llvm/include/llvm/IR/FixedMetadataKinds.def b/llvm/include/llvm/IR/FixedMetadataKinds.def
index 02a986d42f1933..a239a076d131f7 100644
--- a/llvm/include/llvm/IR/FixedMetadataKinds.def
+++ b/llvm/include/llvm/IR/FixedMetadataKinds.def
@@ -53,6 +53,6 @@ LLVM_FIXED_MD_KIND(MD_DIAssignID, "DIAssignID", 38)
 LLVM_FIXED_MD_KIND(MD_coro_outside_frame, "coro.outside.frame", 39)
 LLVM_FIXED_MD_KIND(MD_mmra, "mmra", 40)
 LLVM_FIXED_MD_KIND(MD_noalias_addrspace, "noalias.addrspace", 41)
-// [jderezende] TODO: this will likelly be placed somewhere else,
+// TODO: this will likelly be placed somewhere else,
 // so we don't mix dxil/hlsl/spirv and clang metadata
 LLVM_FIXED_MD_KIND(MD_dxil_controlflow_hints, "dx.controlflow.hints", 42)
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index f3f78fb4f2bdbb..4903185309328e 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -32,7 +32,6 @@
 #include "llvm/CodeGen/Register.h"
 #include "llvm/CodeGen/TargetOpcodes.h"
 #include "llvm/IR/IntrinsicsSPIRV.h"
-#include "llvm/IR/Metadata.h"
 #include "llvm/Support/Debug.h"
 
 #define DEBUG_TYPE "spirv-isel"
diff --git a/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp b/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp
index 7d5617919df87c..3800aac70df327 100644
--- a/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVMetadata.cpp
@@ -12,7 +12,6 @@
 //===----------------------------------------------------------------------===//
 
 #include "SPIRVMetadata.h"
-#include "llvm/IR/Metadata.h"
 
 using namespace llvm;
 
@@ -82,4 +81,5 @@ MDString *getOCLKernelArgTypeQual(const Function &F, unsigned ArgIdx) {
       "Kernel attributes are attached/belong only to OpenCL kernel functions");
   return getOCLKernelArgAttribute(F, ArgIdx, "kernel_arg_type_qual");
 }
+
 } // namespace llvm
diff --git a/llvm/test/CodeGen/DirectX/HLSLBranchHint.ll b/llvm/test/CodeGen/DirectX/HLSLBranchHint.ll
new file mode 100644
index 00000000000000..e7128d19283e80
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/HLSLBranchHint.ll
@@ -0,0 +1,95 @@
+; RUN: opt -S -dxil-op-lower -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s
+
+; This test make sure LLVM metadata is propagating to DXIL.
+
+
+; CHECK: define i32 @test_branch(i32 %X)
+; CHECK: br i1 %cmp, label %if.then, label %if.else, !dx.controlflow.hints [[HINT_BRANCH:![0-9]+]]
+define i32 @test_branch(i32 %X) {
+entry:
+  %X.addr = alloca i32, align 4
+  %resp = alloca i32, align 4
+  store i32 %X, ptr %X.addr, align 4
+  %0 = load i32, ptr %X.addr, align 4
+  %cmp = icmp sgt i32 %0, 0
+  br i1 %cmp, label %if.then, label %if.else, !dx.controlflow.hints !0
+
+if.then:                                          ; preds = %entry
+  %1 = load i32, ptr %X.addr, align 4
+  %sub = sub nsw i32 0, %1
+  store i32 %sub, ptr %resp, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %2 = load i32, ptr %X.addr, align 4
+  %mul = mul nsw i32 %2, 2
+  store i32 %mul, ptr %resp, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %3 = load i32, ptr %resp, align 4
+  ret i32 %3
+}
+
+
+; CHECK: define i32 @test_flatten(i32 %X)
+; CHECK: br i1 %cmp, label %if.then, label %if.else, !dx.controlflow.hints [[HINT_FLATTEN:![0-9]+]]
+define i32 @test_flatten(i32 %X) {
+entry:
+  %X.addr = alloca i32, align 4
+  %resp = alloca i32, align 4
+  store i32 %X, ptr %X.addr, align 4
+  %0 = load i32, ptr %X.addr, align 4
+  %cmp = icmp sgt i32 %0, 0
+  br i1 %cmp, label %if.then, label %if.else, !dx.controlflow.hints !1
+
+if.then:                                          ; preds = %entry
+  %1 = load i32, ptr %X.addr, align 4
+  %sub = sub nsw i32 0, %1
+  store i32 %sub, ptr %resp, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %2 = load i32, ptr %X.addr, align 4
+  %mul = mul nsw i32 %2, 2
+  store i32 %mul, ptr %resp, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %3 = load i32, ptr %resp, align 4
+  ret i32 %3
+}
+
+
+; CHECK: define i32 @test_no_attr(i32 %X)
+; CHECK-NO: !dx.controlflow.hints
+define i32 @test_no_attr(i32 %X) {
+entry:
+  %X.addr = alloca i32, align 4
+  %resp = alloca i32, align 4
+  store i32 %X, ptr %X.addr, align 4
+  %0 = load i32, ptr %X.addr, align 4
+  %cmp = icmp sgt i32 %0, 0
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  %1 = load i32, ptr %X.addr, align 4
+  %sub = sub nsw i32 0, %1
+  store i32 %sub, ptr %resp, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %2 = load i32, ptr %X.addr, align 4
+  %mul = mul nsw i32 %2, 2
+  store i32 %mul, ptr %resp, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %3 = load i32, ptr %resp, align 4
+  ret i32 %3
+}
+
+; CHECK: [[HINT_BRANCH]] = !{!"dx.controlflow.hints", i32 1}
+; CHECK: [[HINT_FLATTEN]] = !{!"dx.controlflow.hints", i32 2}
+!0 = !{!"dx.controlflow.hints", i32 1}
+!1 = !{!"dx.controlflow.hints", i32 2}
diff --git a/llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll b/llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll
new file mode 100644
index 00000000000000..771f5603cf526f
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll
@@ -0,0 +1,91 @@
+; RUN: llc -O0 -mtriple=spirv-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+
+define spir_func noundef i32 @test_branch(i32 noundef %X) {
+entry:
+; CHECK-LABEL: ; -- Begin function test_branch
+; OpSelectionMerge %[[#]] DontFlatten
+  %X.addr = alloca i32, align 4
+  %resp = alloca i32, align 4
+  store i32 %X, ptr %X.addr, align 4
+  %0 = load i32, ptr %X.addr, align 4
+  %cmp = icmp sgt i32 %0, 0
+  br i1 %cmp, label %if.then, label %if.else, !dx.controlflow.hints !0
+
+if.then:                                          ; preds = %entry
+  %1 = load i32, ptr %X.addr, align 4
+  %sub = sub nsw i32 0, %1
+  store i32 %sub, ptr %resp, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %2 = load i32, ptr %X.addr, align 4
+  %mul = mul nsw i32 %2, 2
+  store i32 %mul, ptr %resp, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %3 = load i32, ptr %resp, align 4
+  ret i32 %3
+}
+
+
+define spir_func noundef i32 @test_flatten(i32 noundef %X) {
+entry:
+; CHECK-LABEL: ; -- Begin function test_flatten
+; OpSelectionMerge %[[#]] Flatten
+  %X.addr = alloca i32, align 4
+  %resp = alloca i32, align 4
+  store i32 %X, ptr %X.addr, align 4
+  %0 = load i32, ptr %X.addr, align 4
+  %cmp = icmp sgt i32 %0, 0
+  br i1 %cmp, label %if.then, label %if.else, !dx.controlflow.hints !1
+
+if.then:                                          ; preds = %entry
+  %1 = load i32, ptr %X.addr, align 4
+  %sub = sub nsw i32 0, %1
+  store i32 %sub, ptr %resp, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %2 = load i32, ptr %X.addr, align 4
+  %mul = mul nsw i32 %2, 2
+  store i32 %mul, ptr %resp, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %3 = load i32, ptr %resp, align 4
+  ret i32 %3
+}
+
+define spir_func noundef i32 @test_no_attr(i32 noundef %X) {
+entry:
+; CHECK-LABEL: ; -- Begin function test_no_attr
+; OpSelectionMerge %[[#]] None
+  %X.addr = alloca i32, align 4
+  %resp = alloca i32, align 4
+  store i32 %X, ptr %X.addr, align 4
+  %0 = load i32, ptr %X.addr, align 4
+  %cmp = icmp sgt i32 %0, 0
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:                                          ; preds = %entry
+  %1 = load i32, ptr %X.addr, align 4
+  %sub = sub nsw i32 0, %1
+  store i32 %sub, ptr %resp, align 4
+  br label %if.end
+
+if.else:                                          ; preds = %entry
+  %2 = load i32, ptr %X.addr, align 4
+  %mul = mul nsw i32 %2, 2
+  store i32 %mul, ptr %resp, align 4
+  br label %if.end
+
+if.end:                                           ; preds = %if.else, %if.then
+  %3 = load i32, ptr %resp, align 4
+  ret i32 %3
+}
+
+!0 = !{!"dx.controlflow.hints", i32 1}
+!1 = !{!"dx.controlflow.hints", i32 2}

>From 4c33ffb6a243a278583e79eb0694a5cd8a016e6a Mon Sep 17 00:00:00 2001
From: Joao Saffran <jderezende at microsoft.com>
Date: Fri, 15 Nov 2024 18:48:14 +0000
Subject: [PATCH 5/6] fixing spirv failures

---
 llvm/include/llvm/IR/IntrinsicsSPIRV.td       |  2 +-
 .../Target/SPIRV/SPIRVInstructionSelector.cpp |  5 +--
 llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp   | 35 ++++++++++---------
 .../{ => structurizer}/HLSLBranchHint.ll      |  0
 4 files changed, 22 insertions(+), 20 deletions(-)
 rename llvm/test/CodeGen/SPIRV/{ => structurizer}/HLSLBranchHint.ll (100%)

diff --git a/llvm/include/llvm/IR/IntrinsicsSPIRV.td b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
index 4a5f744c74d9be..f29eb7ee22b2d2 100644
--- a/llvm/include/llvm/IR/IntrinsicsSPIRV.td
+++ b/llvm/include/llvm/IR/IntrinsicsSPIRV.td
@@ -33,7 +33,7 @@ let TargetPrefix = "spv" in {
   def int_spv_ptrcast : Intrinsic<[llvm_any_ty], [llvm_any_ty, llvm_metadata_ty, llvm_i32_ty], [ImmArg<ArgIndex<2>>]>;
   def int_spv_switch : Intrinsic<[], [llvm_any_ty, llvm_vararg_ty]>;
   def int_spv_loop_merge : Intrinsic<[], [llvm_vararg_ty]>;
-  def int_spv_selection_merge : Intrinsic<[], [llvm_metadata_ty, llvm_vararg_ty]>;
+  def int_spv_selection_merge : Intrinsic<[], [llvm_vararg_ty]>;
   def int_spv_cmpxchg : Intrinsic<[llvm_i32_ty], [llvm_any_ty, llvm_vararg_ty]>;
   def int_spv_unreachable : Intrinsic<[], []>;
   def int_spv_alloca : Intrinsic<[llvm_any_ty], []>;
diff --git a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
index 4903185309328e..5576f46cf89f9a 100644
--- a/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp
@@ -2706,7 +2706,8 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
   case Intrinsic::spv_selection_merge: {
 
     auto SelectionControl = SPIRV::SelectionControl::None;
-    const MDNode *MDOp = I.getOperand(1).getMetadata();
+    const MDNode *MDOp =
+        I.getOperand(I.getNumExplicitOperands() - 1).getMetadata();
     if (MDOp->getNumOperands() > 0) {
       ConstantInt *BranchHint =
           mdconst::extract<ConstantInt>(MDOp->getOperand(1));
@@ -2721,7 +2722,7 @@ bool SPIRVInstructionSelector::selectIntrinsic(Register ResVReg,
 
     auto MIB =
         BuildMI(BB, I, I.getDebugLoc(), TII.get(SPIRV::OpSelectionMerge));
-    for (unsigned i = 2; i < I.getNumExplicitOperands(); ++i) {
+    for (unsigned i = 1; i < I.getNumExplicitOperands() - 1; ++i) {
       assert(I.getOperand(i).isMBB());
       MIB.addMBB(I.getOperand(i).getMBB());
     }
diff --git a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
index 6fed0b81bf61e7..1d837296ddc647 100644
--- a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
@@ -13,18 +13,17 @@
 #include "SPIRVSubtarget.h"
 #include "SPIRVTargetMachine.h"
 #include "SPIRVUtils.h"
-#include "llvm-c/Core.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/CodeGen/IntrinsicLowering.h"
+#include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/IntrinsicsSPIRV.h"
-#include "llvm/IR/Metadata.h"
 #include "llvm/IR/ProfDataUtils.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Transforms/Utils/Cloning.h"
@@ -98,7 +97,7 @@ BasicBlock *getDesignatedMergeBlock(Instruction *I) {
       II->getIntrinsicID() != Intrinsic::spv_selection_merge)
     return nullptr;
 
-  BlockAddress *BA = cast<BlockAddress>(II->getOperand(1));
+  BlockAddress *BA = cast<BlockAddress>(II->getOperand(0));
   return BA->getBasicBlock();
 }
 
@@ -647,14 +646,7 @@ class SPIRVStructurizer : public FunctionPass {
       Builder.SetInsertPoint(Header->getTerminator());
 
       auto MergeAddress = BlockAddress::get(BB.getParent(), &BB);
-
-      MDNode *BranchMdNode = getDxBranchHint(*Header->getTerminator());
-      Value *MDNodeValue =
-          MetadataAsValue::get(Builder.getContext(), BranchMdNode);
-
-      SmallVector<Value *, 2> Args = {MDNodeValue, MergeAddress};
-
-      Builder.CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
+      createOpSelectMerge(&Builder, MergeAddress);
 
       Modified = true;
     }
@@ -776,10 +768,9 @@ class SPIRVStructurizer : public FunctionPass {
       BasicBlock *Merge = Candidates[0];
 
       auto MergeAddress = BlockAddress::get(Merge->getParent(), Merge);
-      SmallVector<Value *, 1> Args = {MergeAddress};
       IRBuilder<> Builder(&BB);
       Builder.SetInsertPoint(BB.getTerminator());
-      Builder.CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
+      createOpSelectMerge(&Builder, MergeAddress);
     }
 
     return Modified;
@@ -1112,8 +1103,7 @@ class SPIRVStructurizer : public FunctionPass {
         Builder.SetInsertPoint(Header->getTerminator());
 
         auto MergeAddress = BlockAddress::get(Merge->getParent(), Merge);
-        SmallVector<Value *, 1> Args = {MergeAddress};
-        Builder.CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
+        createOpSelectMerge(&Builder, MergeAddress);
         continue;
       }
 
@@ -1127,8 +1117,7 @@ class SPIRVStructurizer : public FunctionPass {
       Builder.SetInsertPoint(Header->getTerminator());
 
       auto MergeAddress = BlockAddress::get(NewMerge->getParent(), NewMerge);
-      SmallVector<Value *, 1> Args = {MergeAddress};
-      Builder.CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
+      createOpSelectMerge(&Builder, MergeAddress);
     }
 
     return Modified;
@@ -1215,6 +1204,18 @@ class SPIRVStructurizer : public FunctionPass {
     AU.addPreserved<SPIRVConvergenceRegionAnalysisWrapperPass>();
     FunctionPass::getAnalysisUsage(AU);
   }
+
+  void createOpSelectMerge(IRBuilder<> *Builder, BlockAddress *MergeAddress) {
+    Instruction *BBTerminatoInst = Builder->GetInsertBlock()->getTerminator();
+
+    MDNode *BranchMdNode = getDxBranchHint(*BBTerminatoInst);
+    Value *MDNodeValue =
+        MetadataAsValue::get(Builder->getContext(), BranchMdNode);
+
+    llvm::SmallVector<llvm::Value *, 2> Args = {MergeAddress, MDNodeValue};
+
+    Builder->CreateIntrinsic(Intrinsic::spv_selection_merge, {}, {Args});
+  }
 };
 } // namespace llvm
 
diff --git a/llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll b/llvm/test/CodeGen/SPIRV/structurizer/HLSLBranchHint.ll
similarity index 100%
rename from llvm/test/CodeGen/SPIRV/HLSLBranchHint.ll
rename to llvm/test/CodeGen/SPIRV/structurizer/HLSLBranchHint.ll

>From 6d01f396b71282b3be72633d25caa8dda10dc353 Mon Sep 17 00:00:00 2001
From: Joao Saffran <jderezende at microsoft.com>
Date: Fri, 15 Nov 2024 19:29:29 +0000
Subject: [PATCH 6/6] removing headers

---
 llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
index 1d837296ddc647..57285869b2e338 100644
--- a/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
+++ b/llvm/lib/Target/SPIRV/SPIRVStructurizer.cpp
@@ -17,7 +17,6 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/CodeGen/IntrinsicLowering.h"
-#include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/IRBuilder.h"



More information about the llvm-commits mailing list