Removing the special handling in classlibnative for atan2(±∞, ±∞) and pow(-1.0, ±∞). (#10295)

* Removing the special handling in classlibnative for atan2(±∞, ±∞) and pow(-1.0, ±∞).

* Fixing up the logic for HAVE_COMPATIBLE_POW in the PAL layer.

2 files changed, 0 insertions, 58 deletions

diff --git a/src/classlibnative/float/floatdouble.cpp b/src/classlibnative/float/floatdouble.cpp
index d9603c0636..6f593e503c 100644
--- a/src/classlibnative/float/floatdouble.cpp
+++ b/src/classlibnative/float/floatdouble.cpp
@@ -9,8 +9,6 @@
 
 #include "floatdouble.h"
 
-#define IS_DBL_INFINITY(x)         (((*((INT64*)((void*)&x))) & I64(0x7FFFFFFFFFFFFFFF)) == I64(0x7FF0000000000000))
-
 // The default compilation mode is /fp:precise, which disables floating-point intrinsics. This
 // default compilation mode has previously caused performance regressions in floating-point code.
 // We enable /fp:fast semantics for the majority of the math functions, as it will speed up performance
@@ -86,13 +84,6 @@ FCIMPLEND
 FCIMPL2_VV(double, COMDouble::Atan2, double y, double x)
     FCALL_CONTRACT;
 
-    // atan2(+/-INFINITY, +/-INFINITY) produces +/-0.78539816339744828 (x is +INFINITY) and
-    // +/-2.3561944901923448 (x is -INFINITY) instead of the expected value of NaN. We handle
-    // that case here ourselves.
-    if (IS_DBL_INFINITY(y) && IS_DBL_INFINITY(x)) {
-        return (double)(y / x);
-    }
-
     return (double)atan2(y, x);
 FCIMPLEND
 
@@ -174,24 +165,6 @@ FCIMPLEND
 FCIMPL2_VV(double, COMDouble::Pow, double x, double y)
     FCALL_CONTRACT;
 
-    // The CRT version of pow preserves the NaN payload of x over the NaN payload of y.
-
-    if(_isnan(y)) {
-        return y; // IEEE 754-2008: NaN payload must be preserved
-    }
-
-    if(_isnan(x)) {
-        return x; // IEEE 754-2008: NaN payload must be preserved
-    }
-
-    // The CRT version of pow does not return NaN for pow(-1.0, +/-INFINITY) and
-    // instead returns +1.0.
-
-    if(IS_DBL_INFINITY(y) && (x == -1.0)) {
-        INT64 result = CLR_NAN_64;
-        return (*((double*)((INT64*)&result)));
-    }
-
     return (double)pow(x, y);
 FCIMPLEND
 
diff --git a/src/classlibnative/float/floatsingle.cpp b/src/classlibnative/float/floatsingle.cpp
index c84c0bfb93..c7b7d4126b 100644
--- a/src/classlibnative/float/floatsingle.cpp
+++ b/src/classlibnative/float/floatsingle.cpp
@@ -9,18 +9,12 @@
 
 #include "floatsingle.h"
 
-#define IS_FLT_INFINITY(x)         (((*((INT32*)((void*)&x))) & 0x7FFFFFFF) == 0x7F800000)
-
 // Windows x86 and Windows ARM/ARM64 may not define _isnanf() or _copysignf() but they do
 // define _isnan() and _copysign(). We will redirect the macros to these other functions if
 // the macro is not defined for the platform. This has the side effect of a possible implicit
 // upcasting for arguments passed in and an explicit downcasting for the _copysign() call.
 #if (defined(_TARGET_X86_) || defined(_TARGET_ARM_) || defined(_TARGET_ARM64_)) && !defined(FEATURE_PAL)
 
-#if !defined(_isnanf)
-#define _isnanf      _isnan
-#endif
-
 #if !defined(_copysignf)
 #define _copysignf   (float)_copysign
 #endif
@@ -88,13 +82,6 @@ FCIMPLEND
 FCIMPL2_VV(float, COMSingle::Atan2, float y, float x)
     FCALL_CONTRACT;
 
-    // atan2f(+/-INFINITY, +/-INFINITY) produces +/-0.785398163f (x is +INFINITY) and
-    // +/-2.35619449f (x is -INFINITY) instead of the expected value of NaN. We handle
-    // that case here ourselves.
-    if (IS_FLT_INFINITY(y) && IS_FLT_INFINITY(x)) {
-        return (float)(y / x);
-    }
-
     return (float)atan2f(y, x);
 FCIMPLEND
 
@@ -176,24 +163,6 @@ FCIMPLEND
 FCIMPL2_VV(float, COMSingle::Pow, float x, float y)
     FCALL_CONTRACT;
 
-    // The CRT version of pow preserves the NaN payload of x over the NaN payload of y.
-
-    if(_isnanf(y)) {
-        return y; // IEEE 754-2008: NaN payload must be preserved
-    }
-
-    if(_isnanf(x)) {
-        return x; // IEEE 754-2008: NaN payload must be preserved
-    }
-
-    // The CRT version of powf does not return NaN for powf(-1.0f, +/-INFINITY) and
-    // instead returns +1.0f.
-
-    if(IS_FLT_INFINITY(y) && (x == -1.0f)) {
-        INT32 result = CLR_NAN_32;
-        return (*((float*)((INT32*)&result)));
-    }
-
     return (float)powf(x, y);
 FCIMPLEND