mibintc marked 3 inline comments as not done. mibintc added a comment. I added an inline reply and unmarked some things that had been inadvertently marked done.
================ Comment at: clang/lib/CodeGen/CodeGenFunction.cpp:126 + case LangOptions::FPM_Precise: + case LangOptions::FPM_Fast: + break; ---------------- mibintc wrote: > kpn wrote: > > Wait, so "fast" and "precise" are the same thing? That doesn't sound like > > where the documentation you put in the ticket says "the compiler preserves > > the source expression ordering and rounding properties of floating-point". > > > > (Yes, I saw below where "fast" turns on the fast math flags but "precise" > > doesn't. That doesn't affect my point here.) > "precise" doesn't necessitate the use of Constrained Intrinsics, And likewise > for "fast". The words "compiler preserves the source expression ordering" > were copied from the msdn documentation for /fp:precise as you explained it > would be useful to have the msdn documentation for the option in case it goes > offline in, say, 30 years. The ICL Intel compiler also provides equivalent > floating point options. The Intel documentation for precise is phrased > differently "Disables optimizations that are not value-safe on floating-point > data." > > fp-model=precise should enable contractions, if that's not true at default (I > mean, clang -c) then this patch is missing that. > > fp-model=fast is the same as requesting ffast-math Well, we haven't heard from Andy yet, but he told me some time ago that /fp:precise corresponds more or less (there was wiggle room) to clang's default behavior. It sounds like you think the description in the msdn of /fp:precise isn't describing clang's default behavior, @kpn can you say more about that, and do you think that ConstrainedIntrinsics should be created to provide the semantics of /fp:precise? Repository: rL LLVM CHANGES SINCE LAST ACTION https://reviews.llvm.org/D62731/new/ https://reviews.llvm.org/D62731 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
