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Use bit_cast to create -0.0 for floating point types to avoid compiler optimization changing sign with --ffast-math enabled.

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Rasmus Munk Larsen
2021-06-10 19:18:50 -07:00
parent f64b2954c7
commit fc87e2cbaa
6 changed files with 16 additions and 12 deletions
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3
Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
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@@ -839,7 +839,8 @@ Packet psqrt_complex(const Packet& a) {
// Step 4. Compute solution for inputs with negative real part:
// [|eta0|, sign(y0)*rho0, |eta1|, sign(y1)*rho1]
const RealPacket cst_imag_sign_mask = pset1<Packet>(Scalar(RealScalar(0.0), RealScalar(-0.0))).v;
const RealScalar neg_zero = RealScalar(numext::bit_cast<float>(0x80000000u));
const RealPacket cst_imag_sign_mask = pset1<Packet>(Scalar(RealScalar(0.0), neg_zero)).v;
RealPacket imag_signs = pand(a.v, cst_imag_sign_mask);
Packet negative_real_result;
// Notice that rho is positive, so taking it's absolute value is a noop.