Add support for llvm.scmp/ucmp.* (#2741)

Signed-off-by: Marcos Maronas <[email protected]>

Original commit:
KhronosGroup/SPIRV-LLVM-Translator@e16f698506710fd

Author: maarquitos14

llvm-spirv/lib/SPIRV/SPIRVWriter.cpp

@@ -3828,6 +3828,8 @@ bool LLVMToSPIRVBase::isKnownIntrinsic(Intrinsic::ID Id) {
   case Intrinsic::minnum:
   case Intrinsic::smin:
   case Intrinsic::umin:
+  case Intrinsic::scmp:
+  case Intrinsic::ucmp:
   case Intrinsic::nearbyint:
   case Intrinsic::pow:
   case Intrinsic::powi:
@@ -4205,6 +4207,51 @@ SPIRVValue *LLVMToSPIRVBase::transIntrinsicInst(IntrinsicInst *II,
         BM->addCmpInst(OC, transType(BoolTy), FirstArgVal, SecondArgVal, BB);
     return BM->addSelectInst(Cmp, FirstArgVal, SecondArgVal, BB);
   }
+  case Intrinsic::ucmp:
+  case Intrinsic::scmp: {
+    Type *BoolTy = IntegerType::getInt1Ty(M->getContext());
+    SPIRVValue *FirstArgVal = transValue(II->getArgOperand(0), BB);
+    SPIRVValue *SecondArgVal = transValue(II->getArgOperand(1), BB);
+    SPIRVType *ResTy = transType(II->getType());
+    SPIRVValue *One = nullptr;
+    SPIRVValue *Zero = nullptr;
+    SPIRVValue *MinusOne = nullptr;
+    if (auto *VecTy = dyn_cast<VectorType>(II->getType())) {
+      auto *ElemTy = transType(VecTy->getElementType());
+      APInt MinusOneValue(ElemTy->getIntegerBitWidth(), 0, 1);
+      MinusOneValue.setAllBits();
+      unsigned VecSize = VecTy->getElementCount().getFixedValue();
+      auto ElemCount =
+          static_cast<std::vector<SPIRVValue *>::size_type>(VecSize);
+      auto *ElemOne = BM->addConstant(ElemTy, 1);
+      auto *ElemZero = BM->addConstant(ElemTy, 0);
+      auto *ElemMinusOne = BM->addConstant(ElemTy, MinusOneValue);
+      std::vector<SPIRVValue *> ElemsOne(ElemCount, ElemOne);
+      std::vector<SPIRVValue *> ElemsZero(ElemCount, ElemZero);
+      std::vector<SPIRVValue *> ElemsMinusOne(ElemCount, ElemMinusOne);
+      One = BM->addCompositeConstant(ResTy, ElemsOne);
+      Zero = BM->addCompositeConstant(ResTy, ElemsZero);
+      MinusOne = BM->addCompositeConstant(ResTy, ElemsMinusOne);
+    } else {
+      One = BM->addConstant(ResTy, 1);
+      Zero = BM->addConstant(ResTy, 0);
+      APInt MinusOneValue(ResTy->getIntegerBitWidth(), 0, 1);
+      MinusOneValue.setAllBits();
+      MinusOne = BM->addConstant(ResTy, MinusOneValue);
+    }
+
+    Op OC1 = (IID == Intrinsic::scmp) ? OpSLessThanEqual : OpULessThanEqual;
+    Op OC2 = (IID == Intrinsic::scmp) ? OpSLessThan : OpULessThan;
+    if (auto *VecTy = dyn_cast<VectorType>(II->getArgOperand(0)->getType()))
+      BoolTy = VectorType::get(BoolTy, VecTy->getElementCount());
+    SPIRVValue *Cmp1 =
+        BM->addCmpInst(OC1, transType(BoolTy), FirstArgVal, SecondArgVal, BB);
+    SPIRVValue *Cmp2 =
+        BM->addCmpInst(OC2, transType(BoolTy), FirstArgVal, SecondArgVal, BB);
+    auto *ResCmp2 = BM->addSelectInst(Cmp2, MinusOne, Zero, BB);
+    auto *ResCmp1 = BM->addSelectInst(Cmp1, ResCmp2, One, BB);
+    return ResCmp1;
+  }
   case Intrinsic::fma: {
     if (!checkTypeForSPIRVExtendedInstLowering(II, BM))
       break;