[JIT] Add ccmp and enable conditional compares for X64

src/coreclr/jit/codegen.h

@@ -649,6 +649,7 @@ class CodeGen final : public CodeGenInterface
 #if defined(TARGET_AMD64)
     void genAmd64EmitterUnitTestsSse2();
     void genAmd64EmitterUnitTestsApx();
+    void genAmd64EmitterUnitTestsCCMP();
 #endif
 
 #endif // defined(DEBUG)
@@ -911,6 +912,9 @@ class CodeGen final : public CodeGenInterface
 #ifdef TARGET_ARM64
     void genCodeForCCMP(GenTreeCCMP* ccmp);
 #endif
+#ifdef TARGET_AMD64
+    void genCodeForCCMP(GenTreeCCMP* ccmp);
+#endif // TARGET_AMD64
     void genCodeForSelect(GenTreeOp* select);
     void genIntrinsic(GenTreeIntrinsic* treeNode);
     void genPutArgStk(GenTreePutArgStk* treeNode);
@@ -1655,6 +1659,8 @@ class CodeGen final : public CodeGenInterface
     static insOpts ShiftOpToInsOpts(genTreeOps op);
 #elif defined(TARGET_XARCH)
     static instruction JumpKindToCmov(emitJumpKind condition);
+    static instruction JumpKindToCcmp(emitJumpKind condition);
+    static insOpts     OptsFromCFlags(insCflags flags);
 #endif
 
 #if !defined(TARGET_LOONGARCH64) && !defined(TARGET_RISCV64)

src/coreclr/jit/codegenlinear.cpp

@@ -2702,6 +2702,10 @@ void CodeGen::genEmitterUnitTests()
     {
         genAmd64EmitterUnitTestsApx();
     }
+    if (unitTestSectionAll || (strstr(unitTestSection, "ccmp") != nullptr))
+    {
+        genAmd64EmitterUnitTestsCCMP();
+    }
 
 #elif defined(TARGET_ARM64)
     if (unitTestSectionAll || (strstr(unitTestSection, "general") != nullptr))