devtools/eigen
1
0
Fork 0
mirror of https://gitlab.com/libeigen/eigen.git synced 2026-04-10 11:34:33 +08:00
Code Issues Packages Projects Releases Wiki Activity

Improve polynomial evaluation with instruction-level parallelism for pexp_float and pexp<Packet16f>

Browse Source
This commit is contained in:
guoqiangqi
2020-10-20 11:37:09 +08:00
parent 4a77eda1fd
commit 28aef8e816
2 changed files with 21 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
View File

@@ -345,18 +345,18 @@ Packet pexp_float(const Packet _x)
#endif
Packet r2 = pmul(r, r);
Packet r3 = pmul(r2, r);
// TODO(gonnet): Split into odd/even polynomials and try to exploit
// instruction-level parallelism.
Packet y = cst_cephes_exp_p0;
y = pmadd(y, r, cst_cephes_exp_p1);
y = pmadd(y, r, cst_cephes_exp_p2);
y = pmadd(y, r, cst_cephes_exp_p3);
y = pmadd(y, r, cst_cephes_exp_p4);
y = pmadd(y, r, cst_cephes_exp_p5);
y = pmadd(y, r2, r);
y = padd(y, cst_1);
// Evaluate the polynomial approximant,improved by instruction-level parallelism.
Packet y, y1, y2;
y = pmadd(cst_cephes_exp_p0, r, cst_cephes_exp_p1);
y1 = pmadd(cst_cephes_exp_p3, r, cst_cephes_exp_p4);
y2 = padd(r, cst_1);
y = pmadd(y, r, cst_cephes_exp_p2);
y1 = pmadd(y1, r, cst_cephes_exp_p5);
y = pmadd(y, r3, y1);
y = pmadd(y, r2, y2);
// Return 2^m * exp(r).
return pmax(pldexp(y,m), _x);
}