Fix some small bugs in the Sin, Cos, and SinCos impls

Author: tannergooding

src/libraries/System.Numerics.Vectors/tests/GenericVectorTests.cs

@@ -4546,7 +4546,7 @@ public void CosDoubleTest(double value, double expectedResult, double variance)
 
         [Theory]
         [MemberData(nameof(GenericMathTestMemberData.CosSingle), MemberType = typeof(GenericMathTestMemberData))]
-        public void CosCosgleTest(float value, float expectedResult, float variance)
+        public void CosSingleTest(float value, float expectedResult, float variance)
         {
             Vector<float> actualResult = Vector.Cos(Vector.Create(value));
             AssertEqual(Vector.Create(expectedResult), actualResult, Vector.Create(variance));

src/libraries/System.Private.CoreLib/src/System/Runtime/Intrinsics/VectorMath.cs

@@ -211,30 +211,29 @@ public static TVectorSingle CosSingle<TVectorSingle, TVectorInt32, TVectorDouble
             const int ARG_SMALLER = 0x39000000; // 2^-27
 
             TVectorSingle ax = TVectorSingle.Abs(x);
-            TVectorInt32 ux = Unsafe.BitCast<TVectorSingle, TVectorInt32>(x);
+            TVectorInt32 ux = Unsafe.BitCast<TVectorSingle, TVectorInt32>(ax);
 
             TVectorSingle result;
 
-            if (TVectorSingle.LessThanOrEqualAll(ax, TVectorSingle.Create(ARG_LARGE)))
+            if (TVectorInt32.LessThanOrEqualAll(ux, TVectorInt32.Create(ARG_LARGE)))
             {
                 // We must be a finite value: (pi / 4) >= |x|
 
                 if (TVectorInt32.GreaterThanAny(ux, TVectorInt32.Create(ARG_SMALL - 1)))
                 {
                     // at least one element is: |x| >= 2^-13
-                    TVectorSingle x2 = x * x;
 
                     if (TVectorSingle.Count == TVectorDouble.Count)
                     {
                         result = Narrow<TVectorDouble, TVectorSingle>(
-                            CosSingleSmall(Widen<TVectorSingle, TVectorDouble>(x2))
+                            CosSingleSmall(Widen<TVectorSingle, TVectorDouble>(x))
                         );
                     }
                     else
                     {
                         result = Narrow<TVectorDouble, TVectorSingle>(
-                            CosSingleSmall(WidenLower<TVectorSingle, TVectorDouble>(x2)),
-                            CosSingleSmall(WidenUpper<TVectorSingle, TVectorDouble>(x2))
+                            CosSingleSmall(WidenLower<TVectorSingle, TVectorDouble>(x)),
+                            CosSingleSmall(WidenUpper<TVectorSingle, TVectorDouble>(x))
                         );
                     }
                 }
@@ -1838,11 +1837,11 @@ public static (TVectorSingle Sin, TVectorSingle Cos) SinCosSingle<TVectorSingle,
             const int ARG_SMALLER = 0x39000000; // 2^-27
 
             TVectorSingle ax = TVectorSingle.Abs(x);
-            TVectorInt32 ux = Unsafe.BitCast<TVectorSingle, TVectorInt32>(x);
+            TVectorInt32 ux = Unsafe.BitCast<TVectorSingle, TVectorInt32>(ax);
 
             TVectorSingle sinResult, cosResult;
 
-            if (TVectorSingle.LessThanOrEqualAll(ax, TVectorSingle.Create(ARG_LARGE)))
+            if (TVectorInt32.LessThanOrEqualAll(ax, TVectorInt32.Create(ARG_LARGE)))
             {
                 // We must be a finite value: (pi / 4) >= |x|
 
@@ -2183,11 +2182,11 @@ public static TVectorSingle SinSingle<TVectorSingle, TVectorInt32, TVectorDouble
             const int ARG_SMALLER = 0x39000000; // 2^-27
 
             TVectorSingle ax = TVectorSingle.Abs(x);
-            TVectorInt32 ux = Unsafe.BitCast<TVectorSingle, TVectorInt32>(x);
+            TVectorInt32 ux = Unsafe.BitCast<TVectorSingle, TVectorInt32>(ax);
 
             TVectorSingle result;
 
-            if (TVectorSingle.LessThanOrEqualAll(ax, TVectorSingle.Create(ARG_LARGE)))
+            if (TVectorInt32.LessThanOrEqualAll(ax, TVectorInt32.Create(ARG_LARGE)))
             {
                 // We must be a finite value: (pi / 4) >= |x|