On 7/8/20 9:59 PM, Jim Wilson wrote: > On Tue, Jul 7, 2020 at 2:52 AM Kito Cheng <kito.ch...@sifive.com> wrote: >> gcc/ChangeLog: >> * gcc/config/riscv/riscv.md (): New. >> (TP_REGNUM): Ditto. >> * doc/extend.texi (Target Builtins): Add RISC-V built-in section. >> Document __builtin_thread_pointer. >> gcc/testsuite/ChangeLog: >> * gcc.target/riscv/read-thread-pointer.c: New. > > It looks OK to me in general. > > You added builtin_thread_pointer but not builtin_set_thread_pointer. > Maybe we should implement both as long as we are implementing one? If > clang only implements one, maybe it should implement the other also? > This doesn't have to be part of this patch. This could be a separate > issue. > > The builtin_thread_pointer docs looks out-of-date. It is documented > for alpha and SH, but it is implemented in gcc/builtins.c not in the > backends. A scan of md files show that quite a few targets support it > but don't document it. I think it should be documented in the generic > builtins section not in the target dependent builtins sections with > some language that says not all targets support it. This doesn't have > to be part of this patch. This could be a separate issue. > > We have two existing undocumented builtins. __builtin_riscv_fsflags > and __builtin_riscv_frflags for setting or reading the FP flags. I > don't know if anyone uses them though. newlib and glbic both use > extended asms for these operations. This doesn't have to be part of > this patch. This could be a separate issue. > > There is a document https://github.com/riscv/riscv-c-api-doc for > coordinating gcc and llvm work that has an empty list of builtin > functions. I'm not sure if this document is still useful. If this is > a RISC-V specific builtin then it should be listed here, but I don't > think it should be considered a RISC-V specific builtin. There is an > unresolved pull request for the frflags and fsflags builtins. I guess > I forgot about that. > > Jim
LLVM 12 now uses __builtin_thread_pointer, and fails to build with GCC 10 (but builds with GCC 11). Could you consider backporting this one to GCC 10? Thanks, Matthias
