On Fri, May 26, 2017 at 10:55 AM, Marc Glisse <marc.gli...@inria.fr> wrote: > Hello, > > glibc marks fegetround as a pure function. On x86, people tend to use > _MM_GET_ROUNDING_MODE instead, which could benefit from the same. I think it > is safe, but a second opinion would be welcome.
Sounds good. The important part is to keep the dependency to SET_ROUNDING_MODE which is done via claiming both touch global memory. > I could have handled just this builtin, but it seemed better to provide > def_builtin_pure (like "const" already has) since there should be other > builtins that can be marked this way (maybe the gathers?). Should work for gathers. They could even use stronger guarantees, namely a fnspec with "..R" (the pointer argument is only read from directly). Similarly scatter can use ".W" (the pointer argument is only written to directly). Richard. > Bootstrap+testsuite on x86_64-pc-linux-gnu with default languages. > > 2017-05-29 Marc Glisse <marc.gli...@inria.fr> > > gcc/ > * config/i386/i386.c (struct builtin_isa): New field pure_p. > Reorder for compactness. > (def_builtin, def_builtin2, ix86_add_new_builtins): Handle pure_p. > (def_builtin_pure, def_builtin_pure2): New functions. > (ix86_init_mmx_sse_builtins) [__builtin_ia32_stmxcsr]: Mark as pure. > > gcc/testsuite/ > * gcc.target/i386/getround.c: New file. > > -- > Marc Glisse
