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Bug 1259

Summary: Avoid conflicts with Intel Short Vector Math Library
Product: Eigen Reporter: Gael Guennebaud <gael.guennebaud>
Component: Core - vectorizationAssignee: Nobody <eigen.nobody>
Status: NEW ---    
Severity: Optimization CC: chtz, gael.guennebaud, jacob.benoit.1, markos, neumann
Priority: Normal Keywords: JuniorJob
Version: 3.4 (development)   
Hardware: x86 - general   
OS: All   
Whiteboard:
Bug Depends on:    
Bug Blocks: 1687    

Description Gael Guennebaud 2016-07-26 09:28:50 UTC
Recent Intel's compiler are able to automatically vectorize math functions such as cos, exp, etc. through calls to SVML. Apparently, SVML versions are faster than ours, and therefore disabling Eigen's vectorization might lead to faster code...

One possible strategy would be to perform ourself explicit calls to SVML in our pexp, p* functions when the user compiles with -DEIGEN_USE_SVML.
Comment 1 neumann 2019-02-13 12:47:56 UTC
Just a note here:
Visual Studio 2019 ships with SVML intrinsics (svmlintrin.h included by immintrin.h).

Would be nice if Eigen would call those functions using visual studio.
Comment 2 Christoph Hertzberg 2019-02-15 12:47:30 UTC
*** Bug 1681 has been marked as a duplicate of this bug. ***