libm -fno-builtin

[Joseph Myers]

On Mon, 25 Jun 2018, Richard Earnshaw (lists) wrote:

> The canonical example is something like memset.  memset idioms are
> generally quite easy for the compiler to recognize and I've frequently

But -fno-builtin isn't what you want there (it's about recognising the 
semantics of a call to a standard function, as opposed to generating a 
call to a function not called in the source, and GCC always requires libc 
to provide memcpy, memmove, memset and memcmp); to avoid converting loops 
to mem* calls, you need -fno-tree-loop-distribute-patterns.

-- 
Joseph S. Myers
joseph@codesourcery.com