Update Range description

Author: AmrDeveloper

clang/include/clang/CIR/Dialect/IR/CIROps.td

@@ -2843,8 +2843,12 @@ def CIR_ComplexMulOp : CIR_Op<"complex.mul", [
     The `cir.complex.mul` operation takes two complex numbers and returns
     their product.
 
-    Range is used to controls the various implementations for complex
-    multiplication.
+    Range is used to select the implementation used when the operation
+    is lowered to the LLVM dialect. For multiplication, 'improved',
+    'promoted', and 'basic' are all handled equivalently, producing the
+    algebraic formula with no special handling for NaN value. If 'full' is
+    used, a runtime-library function is called if one of the intermediate
+    calculations produced a NaN value.
 
     Example:
 

clang/lib/CIR/Dialect/Transforms/LoweringPrepare.cpp

@@ -167,7 +167,7 @@ static mlir::Value buildComplexBinOpLibCall(
 
   cir::FuncType libFuncTy = cir::FuncType::get(libFuncInputTypes, ty);
 
-  // Inserting a declaration for the runtime function to be used in Complex
+  // Insert a declaration for the runtime function to be used in Complex
   // multiplication and division when needed
   cir::FuncOp libFunc;
   {