LoongArch is a NEW ISA which is different from MIPS (#113564)

* LoongArch is a NEW ISA which is different from MIPS

reference:https://docs.kernel.org/arch/loongarch/introduction.html
Introduction to LoongArch

* Update src/coreclr/jit/codegenlinear.cpp

---------

Co-authored-by: Jan Kotas <[email protected]>
Co-authored-by: Adeel Mujahid <[email protected]>

Author: 3 people

src/coreclr/jit/codegenlinear.cpp

@@ -2484,8 +2484,11 @@ CodeGen::GenIntCastDesc::GenIntCastDesc(GenTreeCast* cast)
         }
 
 #if defined(TARGET_LOONGARCH64) || defined(TARGET_RISCV64)
-        // For LoongArch64's ISA which is same with the MIPS64 ISA, even the instructions of 32bits operation need
-        // the upper 32bits be sign-extended to 64 bits.
+        // TODO-LOONGARCH64:
+        // TODO-RISCV64:
+        // LoongArch64 and RiscV64 ABIs require 32-bit values to be sign-extended to 64-bits.
+        // We apply the sign-extension unconditionally here to avoid corner case bugs, even
+        // though it may not be strictly necessary in all cases.
         m_extendKind = SIGN_EXTEND_INT;
 #else
         m_extendKind = COPY;