[PATCH] D57915: [COFF, ARM64] Remove definitions for _byteswap library functions

Eli Friedman via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Thu Feb 7 15:18:34 PST 2019

efriedma added a comment.

I did some quick testing with MSVC; apparently it inlines the implementations of these functions when optimizations are on.  We definitely want to support inlining these. Since these are commonly used in performance-sensitive code, I'd prefer to implement the required changes to CodeGenFunction::EmitMSVCBuiltinExpr now, rather than chase after weird performance regressions in the future.


I'm not sure how you could end up with a "duplicate symbols" error from the current implementation, though; these functions are marked "static", so they shouldn't conflict with the real _byteswap_* functions.



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