Tweak special case handling in atan2.
diff --git a/Eigen/src/Core/GenericPacketMath.h b/Eigen/src/Core/GenericPacketMath.h
index 4ae3edd..d65c63a 100644
--- a/Eigen/src/Core/GenericPacketMath.h
+++ b/Eigen/src/Core/GenericPacketMath.h
@@ -1233,12 +1233,6 @@
// See https://en.cppreference.com/w/cpp/numeric/math/atan2
// for how corner cases are supposed to be handled according to the
// IEEE floating-point standard (IEC 60559).
-
- // bend two rules:
- // 1) inf / inf == 1
- // 2) 0 / 0 == 0
- // otherwise, evaluate atan(y/x) as usual and shift to the appropriate quadrant
-
const Packet kSignMask = pset1<Packet>(-Scalar(0));
const Packet kZero = pzero(x);
const Packet kOne = pset1<Packet>(Scalar(1));
@@ -1246,21 +1240,16 @@
const Packet x_has_signbit = psignbit(x);
const Packet y_signmask = pand(y, kSignMask);
+ const Packet x_signmask = pand(x, kSignMask);
+ const Packet result_signmask = pxor(y_signmask, x_signmask);
const Packet shift = por(pand(x_has_signbit, kPi), y_signmask);
- const Packet xor_xy = pxor(x, y);
- // if x and y have the same absolute value, then xor(x,y) is zero
- // make sure that neither x nor y is nan
- // furthermore, xor(x,y) has the sign of the result
- const Packet x_and_y_are_same = pand(pcmp_eq(xor_xy, kZero), pcmp_eq(x, x));
- // more strictly, if x and y are both zero, then or(x,y) is zero
- // this implicitly checks for nan
- // the sign of or(x,y) is not meaningful
+ const Packet x_and_y_are_same = pcmp_eq(pabs(x), pabs(y));
const Packet x_and_y_are_zero = pcmp_eq(por(x, y), kZero);
Packet arg = pdiv(y, x);
- arg = pselect(x_and_y_are_same, por(kOne, xor_xy), arg);
- arg = pselect(x_and_y_are_zero, xor_xy, arg);
+ arg = pselect(x_and_y_are_same, por(kOne, result_signmask), arg);
+ arg = pselect(x_and_y_are_zero, result_signmask, arg);
Packet result = patan(arg);
result = padd(result, shift);
