Merge pull request #25618 from charris/backport-25430

TST: Fix test_numeric on riscv64

numpy/core/tests/test_numeric.py

@@ -477,7 +477,14 @@ def setup_method(self):
         self.signd[self.ed] *= -1.
         self.signf[1::6][self.ef[1::6]] = -np.inf
         self.signd[1::6][self.ed[1::6]] = -np.inf
-        self.signf[3::6][self.ef[3::6]] = -np.nan
+        # On RISC-V, many operations that produce NaNs, such as converting
+        # a -NaN from f64 to f32, return a canonical NaN.  The canonical
+        # NaNs are always positive.  See section 11.3 NaN Generation and
+        # Propagation of the RISC-V Unprivileged ISA for more details.
+        # We disable the float32 sign test on riscv64 for -np.nan as the sign
+        # of the NaN will be lost when it's converted to a float32.
+        if platform.processor() != 'riscv64':
+            self.signf[3::6][self.ef[3::6]] = -np.nan
         self.signd[3::6][self.ed[3::6]] = -np.nan
         self.signf[4::6][self.ef[4::6]] = -0.
         self.signd[4::6][self.ed[4::6]] = -0.