[PATCH] D59744: Fix i386 ABI "__m64" type bug

Eli Friedman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Tue Jun 18 15:02:48 PDT 2019


efriedma added a comment.

If we're going to insert emms instructions automatically, it doesn't really make sense to do it in the frontend; the backend could figure out the most efficient placement itself.  (See lib/Target/X86/X86VZeroUpper.cpp, which implements similar logic for AVX.)  The part I'd be worried about is the potential performance hit from calling emms in places where other compilers wouldn't, for code using MMX intrinsics.


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59744/new/

https://reviews.llvm.org/D59744





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