xiongji90 added a comment. In D144454#4142253 <https://reviews.llvm.org/D144454#4142253>, @rjmccall wrote:
> New builtins should be documented in the user manual. > > There are standard pragmas for changing the rounding mode, right? What's the > interaction between the ability to set this dynamically with a builtin call > and those pragmas? Hi, @rjmccall Current status is LLVM has added llvm.get.rounding and llvm.set.rounding intrinsic and has also added "__builtin_flt_rounds" for llvm.get.rounding but there is no corresponding for llvm.set.rounding intrinisc. According to original patch to add llvm.set.rounding: https://reviews.llvm.org/D74729 and LLVM document for this intrinsic: https://llvm.org/docs/LangRef.html#id1506 The introduction of llvm.set.rounding intrinsic can provide same functionality as C library function "fesetround" and avoid unnecessary dependency on C library. Currently, this intrinsic can't benefit C/C++ developers since we don't have a corresponding builtin and we even can't add a C/C++ test for this intrinsic. There may be more use scenario other then normal C/C++ program, for example, in heterogeneous computing, some other device such as GPU may support rounding mode setting in device code, users can invoke __builtin_flt_rounds_set in their source code to use this functionality but they can't use C library functions since it unavailable in GPU or other device. Thanks very much for the review! Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D144454/new/ https://reviews.llvm.org/D144454 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
