Implemented SPV_INTEL_unstructured_loop_controls extension,

that adds a new capability: UnstructuredLoopControlsINTEL
and a new instruction: LoopControlINTEL.

This instruction can be used in place of an OpLoopMerge on
unstructured loops.

This is port of
KhronosGroup/SPIRV-LLVM-Translator@3b6882e

Author: ViacheslavRb

IGC/AdaptorOCL/SPIRV/SPIRVReader.cpp

@@ -1478,7 +1478,8 @@ class SPIRVToLLVM {
   template<class Source, class Func>
   bool foreachFuncCtlMask(Source, Func);
 
-  void setLLVMLoopMetadata(SPIRVLoopMerge* LM, BranchInst* BI);
+  template <typename LoopInstType>
+  void setLLVMLoopMetadata(LoopInstType* LM, BranchInst* BI);
   inline llvm::Metadata *getMetadataFromName(std::string Name);
   inline std::vector<llvm::Metadata *>
     getMetadataFromNameAndParameter(std::string Name, SPIRVWord Parameter);
@@ -1707,7 +1708,8 @@ SPIRVToLLVM::getMetadataFromNameAndParameter(std::string Name,
 }
 
 
-void SPIRVToLLVM::setLLVMLoopMetadata(SPIRVLoopMerge *LM, BranchInst *BI) {
+template <typename LoopInstType>
+void SPIRVToLLVM::setLLVMLoopMetadata(LoopInstType* LM, BranchInst* BI) {
   if (!LM)
     return;
   auto Temp = MDNode::getTemporary(*Context, None);
@@ -2817,9 +2819,14 @@ SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       dyn_cast<BasicBlock>(transValue(BR->getTargetLabel(), F, BB)), BB);
 
     SPIRVInstruction *Prev = BR->getPrevious();
-    if(Prev && Prev->getOpCode() == OpLoopMerge)
-      if (auto LM = static_cast<SPIRVLoopMerge *>(Prev))
-        setLLVMLoopMetadata(LM, BI);
+    if(Prev && Prev->getOpCode() == OpLoopMerge) {
+      auto LM = static_cast<SPIRVLoopMerge*>(Prev);
+      setLLVMLoopMetadata<SPIRVLoopMerge>(LM, BI);
+    }
+    else if (Prev && Prev->getOpCode() == OpLoopControlINTEL) {
+      auto LCI = static_cast<SPIRVLoopControlINTEL*>(Prev);
+      setLLVMLoopMetadata<SPIRVLoopControlINTEL>(LCI, BI);
+    }
 
     return mapValue(BV, BI);
     }
@@ -2836,9 +2843,14 @@ SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       BB);
 
     SPIRVInstruction *Prev = BR->getPrevious();
-    if (Prev && Prev->getOpCode() == OpLoopMerge)
+    if (Prev && Prev->getOpCode() == OpLoopMerge) {
       if (auto LM = static_cast<SPIRVLoopMerge *>(Prev))
-        setLLVMLoopMetadata(LM, BC);
+        setLLVMLoopMetadata<SPIRVLoopMerge>(LM, BC);
+    }
+    else if (Prev && Prev->getOpCode() == OpLoopControlINTEL) {
+      if (auto LCI = static_cast<SPIRVLoopControlINTEL *>(Prev))
+        setLLVMLoopMetadata<SPIRVLoopControlINTEL>(LCI, BC);
+    }
 
     return mapValue(BV, BC);
     }
@@ -3014,7 +3026,9 @@ SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
     break;
   // OpenCL Compiler does not use this instruction
   // Should be translated at OpBranch or OpBranchConditional cases
-  case OpLoopMerge: {
+  case OpLoopMerge:
+  case OpLoopControlINTEL:
+    {
     return nullptr;
     }
     break;

IGC/AdaptorOCL/SPIRV/libSPIRV/SPIRVInstruction.h

@@ -1080,6 +1080,52 @@ typedef SPIRVAccessChainGeneric<OpPtrAccessChain, 5> SPIRVPtrAccessChain;
 typedef SPIRVAccessChainGeneric<OpInBoundsPtrAccessChain, 5>
   SPIRVInBoundsPtrAccessChain;
 
+class SPIRVLoopControlINTEL : public SPIRVInstruction {
+public:
+    static const Op OC = OpLoopControlINTEL;
+    static const SPIRVWord FixedWordCount = 2;
+
+    SPIRVLoopControlINTEL(SPIRVWord TheLoopControl,
+        std::vector<SPIRVWord> TheLoopControlParameters,
+        SPIRVBasicBlock* BB)
+        : SPIRVInstruction(FixedWordCount + TheLoopControlParameters.size(), OC,
+            BB),
+        LoopControl(TheLoopControl),
+        LoopControlParameters(TheLoopControlParameters) {
+        validate();
+        IGC_ASSERT_MESSAGE(BB, "Invalid BB");
+    }
+
+    SPIRVLoopControlINTEL() : SPIRVInstruction(OC), LoopControl(SPIRVWORD_MAX) {
+        setHasNoId();
+        setHasNoType();
+    }
+
+    SPIRVWord getLoopControl() { return LoopControl; }
+
+    std::vector<SPIRVWord> getLoopControlParameters() {
+        return LoopControlParameters;
+    }
+
+    CapVec getRequiredCapability() const override {
+        return getVec(CapabilityUnstructuredLoopControlsINTEL);
+    }
+
+//    SPIRVExtSet getRequiredExtensions() const override {        // getRequiredExtensions() is not supported yet
+//        return getSet(SPV_INTEL_unstructured_loop_controls);
+//    }
+
+    void setWordCount(SPIRVWord TheWordCount) override {
+        SPIRVEntry::setWordCount(TheWordCount);
+        LoopControlParameters.resize(TheWordCount - FixedWordCount);
+    }
+    _SPIRV_DEF_DEC2(LoopControl, LoopControlParameters)
+
+protected:
+    SPIRVWord LoopControl;
+    std::vector<SPIRVWord> LoopControlParameters;
+};
+
 template<Op OC, SPIRVWord FixedWordCount>
 class SPIRVFunctionCallGeneric: public SPIRVInstruction {
 public:

IGC/AdaptorOCL/SPIRV/libSPIRV/SPIRVModule.cpp

@@ -215,13 +215,12 @@ class SPIRVModuleImpl : public SPIRVModule {
   virtual SPIRVValue *addConstant(SPIRVValue *) override;
   virtual SPIRVValue *addConstant(SPIRVType *, uint64_t) override;
 
+  // Instruction creation functions
   virtual SPIRVInstruction *addLoopMergeInst(
       SPIRVId MergeBlock, SPIRVId ContinueTarget,
       SPIRVWord LoopControl,
       std::vector<SPIRVWord> LoopControlParameters,
       SPIRVBasicBlock *BB) override;
-
-  // Instruction creation functions
   virtual SPIRVInstruction *
   addInstruction(SPIRVInstruction *Inst, SPIRVBasicBlock *BB,
                  SPIRVInstruction *InsertBefore = nullptr);

IGC/AdaptorOCL/SPIRV/libSPIRV/SPIRVOpCodeEnum.h

@@ -507,3 +507,4 @@ _SPIRV_OP(SubgroupAvcSicGetInterRawSadsINTEL, 5816)
 _SPIRV_OP(VariableLengthArrayINTEL, 5818)
 _SPIRV_OP(SaveMemoryINTEL, 5819)
 _SPIRV_OP(RestoreMemoryINTEL, 5820)
+_SPIRV_OP(LoopControlINTEL, 5887)

IGC/AdaptorOCL/SPIRV/libSPIRV/spirv.hpp

@@ -613,6 +613,7 @@ enum Capability {
     CapabilitySubgroupAvcMotionEstimationIntraINTEL = 5697,
     CapabilitySubgroupAvcMotionEstimationChromaINTEL = 5698,
     CapabilityVariableLengthArrayINTEL = 5817,
+    CapabilityUnstructuredLoopControlsINTEL = 5886,
 };
 
 enum Op {