Translate llvm.ldexp.* intrinsics. (#3608)

Add translation for `llvm.ldexp.*` intrinsics which are mapped to OpenCL
extended instructions.

Author: maarquitos14

lib/SPIRV/SPIRVUtil.cpp

@@ -1958,6 +1958,7 @@ bool checkTypeForSPIRVExtendedInstLowering(IntrinsicInst *II, SPIRVModule *BM) {
   case Intrinsic::fabs:
   case Intrinsic::floor:
   case Intrinsic::fma:
+  case Intrinsic::ldexp:
   case Intrinsic::log:
   case Intrinsic::log10:
   case Intrinsic::log2:

lib/SPIRV/SPIRVWriter.cpp

@@ -4163,6 +4163,8 @@ static SPIRVWord getBuiltinIdForIntrinsic(Intrinsic::ID IID) {
     return OpenCLLIB::Floor;
   case Intrinsic::fma:
     return OpenCLLIB::Fma;
+  case Intrinsic::ldexp:
+    return OpenCLLIB::Ldexp;
   case Intrinsic::frexp:
     return OpenCLLIB::Frexp;
   case Intrinsic::log:
@@ -4463,6 +4465,7 @@ SPIRVValue *LLVMToSPIRVBase::transIntrinsicInst(IntrinsicInst *II,
   // Binary FP intrinsics
   case Intrinsic::atan2:
   case Intrinsic::copysign:
+  case Intrinsic::ldexp:
   case Intrinsic::pow:
   case Intrinsic::powi:
   case Intrinsic::maximumnum:

test/llvm-intrinsics/fp-intrinsics.ll

@@ -482,3 +482,17 @@ entry:
 }
 
 declare {double, double} @llvm.modf.f64(double)
+
+; CHECK: Function
+; CHECK: FunctionParameter {{[0-9]+}} [[x:[0-9]+]]
+; CHECK: FunctionParameter {{[0-9]+}} [[exp:[0-9]+]]
+; CHECK: ExtInst [[var1]] {{[0-9]+}} [[extinst_id]] ldexp [[x]] [[exp]]
+; CHECK: FunctionEnd
+
+define spir_func float @TestLdexp(float %x, i32 %exp) {
+entry:
+  %t = tail call float @llvm.ldexp.f32.i32(float %x, i32 %exp)
+  ret float %t
+}
+
+declare float @llvm.ldexp.f32.i32(float, i32)