Ensure mini-amd64 correctly handles CMP_GT and CMP_GE for OP_XCOMPARE_FP (#104206)

* Ensure mini-amd64 correctly handles CMP_GT and CMP_GE for OP_XCOMPARE_FP

* Re-enable the tests disabled due to #97176

Author: tannergooding

src/libraries/System.Runtime.Intrinsics/tests/Vectors/Vector128Tests.cs

@@ -4826,7 +4826,6 @@ private static void TestCreateSequence<T>(T start, T step)
 
         [Theory]
         [MemberData(nameof(VectorTestMemberData.ExpDouble), MemberType = typeof(VectorTestMemberData))]
-        [SkipOnMono("https://github.com/dotnet/runtime/issues/97176")]
         public void ExpDoubleTest(double value, double expectedResult, double variance)
         {
             Vector128<double> actualResult = Vector128.Exp(Vector128.Create(value));
@@ -4835,7 +4834,6 @@ public void ExpDoubleTest(double value, double expectedResult, double variance)
 
         [Theory]
         [MemberData(nameof(VectorTestMemberData.ExpSingle), MemberType = typeof(VectorTestMemberData))]
-        [SkipOnMono("https://github.com/dotnet/runtime/issues/97176")]
         public void ExpSingleTest(float value, float expectedResult, float variance)
         {
             Vector128<float> actualResult = Vector128.Exp(Vector128.Create(value));

src/libraries/System.Runtime.Intrinsics/tests/Vectors/Vector256Tests.cs

@@ -5841,7 +5841,6 @@ private static void TestCreateSequence<T>(T start, T step)
 
         [Theory]
         [MemberData(nameof(VectorTestMemberData.ExpDouble), MemberType = typeof(VectorTestMemberData))]
-        [SkipOnMono("https://github.com/dotnet/runtime/issues/97176")]
         public void ExpDoubleTest(double value, double expectedResult, double variance)
         {
             Vector256<double> actualResult = Vector256.Exp(Vector256.Create(value));
@@ -5850,7 +5849,6 @@ public void ExpDoubleTest(double value, double expectedResult, double variance)
 
         [Theory]
         [MemberData(nameof(VectorTestMemberData.ExpSingle), MemberType = typeof(VectorTestMemberData))]
-        [SkipOnMono("https://github.com/dotnet/runtime/issues/97176")]
         public void ExpSingleTest(float value, float expectedResult, float variance)
         {
             Vector256<float> actualResult = Vector256.Exp(Vector256.Create(value));

src/libraries/System.Runtime.Intrinsics/tests/Vectors/Vector512Tests.cs

@@ -5274,7 +5274,6 @@ private static void TestCreateSequence<T>(T start, T step)
 
         [Theory]
         [MemberData(nameof(VectorTestMemberData.ExpDouble), MemberType = typeof(VectorTestMemberData))]
-        [SkipOnMono("https://github.com/dotnet/runtime/issues/97176")]
         public void ExpDoubleTest(double value, double expectedResult, double variance)
         {
             Vector512<double> actualResult = Vector512.Exp(Vector512.Create(value));
@@ -5283,7 +5282,6 @@ public void ExpDoubleTest(double value, double expectedResult, double variance)
 
         [Theory]
         [MemberData(nameof(VectorTestMemberData.ExpSingle), MemberType = typeof(VectorTestMemberData))]
-        [SkipOnMono("https://github.com/dotnet/runtime/issues/97176")]
         public void ExpSingleTest(float value, float expectedResult, float variance)
         {
             Vector512<float> actualResult = Vector512.Exp(Vector512.Create(value));

src/mono/mono/mini/mini-amd64.c

@@ -4072,8 +4072,26 @@ mono_arch_lowering_pass (MonoCompile *cfg, MonoBasicBlock *bb)
 			case CMP_NE: ins->inst_c0 = 4; break;
 			case CMP_LT: ins->inst_c0 = 1; break;
 			case CMP_LE: ins->inst_c0 = 2; break;
-			case CMP_GT: ins->inst_c0 = 6; break;
-			case CMP_GE: ins->inst_c0 = 5; break;
+			case CMP_GT: {
+				// CMPNLT (5) is not the same as CMPGT due to NaN
+				// as such, we want to emit CMPLT (1) with swapped
+				// operands instead, ensuring we get correct handling
+				int tmp = ins->sreg1;
+				ins->sreg1 = ins->sreg2;
+				ins->sreg2 = tmp;
+				ins->inst_c0 = 1;
+				break;
+			}
+			case CMP_GE: {
+				// CMPNLE (6) is not the same as CMPGE due to NaN
+				// as such, we want to emit CMPLE (2) with swapped
+				// operands instead, ensuring we get correct handling
+				int tmp = ins->sreg1;
+				ins->sreg1 = ins->sreg2;
+				ins->sreg2 = tmp;
+				ins->inst_c0 = 2;
+				break;
+			}
 			default:
 				g_assert_not_reached();
 				break;