Handle casts done via helpers and fold overflow operations in value n…

…umbering (dotnet#50450)

* Added a missing license header

* Added a test verifying that checked arithmetic is correct

* Added a test verifying that checked casts are correct

* Refactored VNEvalShouldFold

* Refactored gtFoldExprConst to use helpers and follow the common code style

* Fixed the comment stating TYP_BYREF has no zero value

* Moved checking of overflow for arithmetic operations from gtFoldExprConst into a separate namespace

* Implemented folding of overflow arithmetic in value numbering

* Fixed some typos in valuenum.cpp/h

* Added identity-based evaluation for overflow arithmetic

* Refactored gtFoldExpr some more, moved the overflow checking logic to CheckedOps, implemented overflow checking for floating point -> integer casts

* Implemented folding of checked casts in value numbering, started value numbering casts via helpers like normal casts

* Fixed the formatting

* Made the definition of var_types a standalone header so that it can be safely #included'ed in utils.h

* Replaced uses of GTF_CALL_M_SPECIAL_INTRINSIC with the equivalent helpers

* Fold cast via helpers in morph

* Disable the test for checked casts on Mono

src/coreclr/jit/CMakeLists.txt

@@ -248,6 +248,7 @@ if (CLR_CMAKE_TARGET_WIN32)
     valuenumtype.h
     varset.h
     vartype.h
+    vartypesdef.h
   )
 
   if (CLR_CMAKE_TARGET_ARCH_ARM64 OR CLR_CMAKE_TARGET_ARCH_ARM)

src/coreclr/jit/assertionprop.cpp

@@ -4986,6 +4986,9 @@ GenTree* Compiler::optExtractSideEffListFromConst(GenTree* tree)
         bool ignoreRoot = true;
 
         gtExtractSideEffList(tree, &sideEffList, GTF_SIDE_EFFECT, ignoreRoot);
+
+        JITDUMP("Extracted side effects from a constant tree [%06u]:\n", tree->gtTreeID);
+        DISPTREE(sideEffList);
     }
 
     return sideEffList;