MAINT: Avoid dereferencing/strict aliasing warnings during complex casts in npy_math.h for C++ runs (#28892)

ilayn · charris · commit 87d1d8a0dc43 · 2025-05-06T15:01:17.000-06:00
* MAINT: Avoid type-punning complex casts in npy_math.h

* MAINT: Add missing typecast in npy_cimagl
diff --git a/numpy/_core/include/numpy/npy_math.h b/numpy/_core/include/numpy/npy_math.h
@@ -363,7 +363,7 @@ NPY_INPLACE npy_longdouble npy_heavisidel(npy_longdouble x, npy_longdouble h0);
 static inline double npy_creal(const npy_cdouble z)
 {
 #if defined(__cplusplus)
-    return ((double *) &z)[0];
+    return z._Val[0];
 #else
     return creal(z);
 #endif
@@ -377,7 +377,7 @@ static inline void npy_csetreal(npy_cdouble *z, const double r)
 static inline double npy_cimag(const npy_cdouble z)
 {
 #if defined(__cplusplus)
-    return ((double *) &z)[1];
+    return z._Val[1];
 #else
     return cimag(z);
 #endif
@@ -391,7 +391,7 @@ static inline void npy_csetimag(npy_cdouble *z, const double i)
 static inline float npy_crealf(const npy_cfloat z)
 {
 #if defined(__cplusplus)
-    return ((float *) &z)[0];
+    return z._Val[0];
 #else
     return crealf(z);
 #endif
@@ -405,7 +405,7 @@ static inline void npy_csetrealf(npy_cfloat *z, const float r)
 static inline float npy_cimagf(const npy_cfloat z)
 {
 #if defined(__cplusplus)
-    return ((float *) &z)[1];
+    return z._Val[1];
 #else
     return cimagf(z);
 #endif
@@ -419,7 +419,7 @@ static inline void npy_csetimagf(npy_cfloat *z, const float i)
 static inline npy_longdouble npy_creall(const npy_clongdouble z)
 {
 #if defined(__cplusplus)
-    return ((longdouble_t *) &z)[0];
+    return (npy_longdouble)z._Val[0];
 #else
     return creall(z);
 #endif
@@ -433,7 +433,7 @@ static inline void npy_csetreall(npy_clongdouble *z, const longdouble_t r)
 static inline npy_longdouble npy_cimagl(const npy_clongdouble z)
 {
 #if defined(__cplusplus)
-    return ((longdouble_t *) &z)[1];
+    return (npy_longdouble)z._Val[1];
 #else
     return cimagl(z);
 #endif
