On 2023/08/29 6:12, Jeff Law wrote:
>
>
> On 8/9/23 00:11, Tsukasa OI via Gcc-patches wrote:
>> From: Tsukasa OI <research_tra...@irq.a4lg.com>
>>
>> The "pause" RISC-V hint instruction requires the 'Zihintpause' extension
>> (in the assembler). However, GCC emits "pause" unconditionally, making
>> an assembler error while compiling code with __builtin_riscv_pause while
>> the 'Zihintpause' extension disabled.
>>
>> However, the "pause" instruction code (0x0100000f) is a HINT and emitting
>> its instruction code is safe in any environment.
>>
>> This commit implements handling for the 'Zihintpause' extension and emits
>> ".insn 0x0100000f" instead of "pause" only if the extension is disabled
>> (making the diagnostics better).
>>
>> gcc/ChangeLog:
>>
>> * common/config/riscv/riscv-common.cc
>> (riscv_ext_version_table): Implement the 'Zihintpause' extension,
>> version 2.0. (riscv_ext_flag_table) Add 'Zihintpause' handling.
>> * config/riscv/riscv-builtins.cc: Remove availability predicate
>> "always" and add "hint_pause" and "hint_pause_pseudo", corresponding
>> the existence of the 'Zihintpause' extension.
>> (riscv_builtins) Split builtin implementation depending on the
>> existence of the 'Zihintpause' extension.
>> * config/riscv/riscv-opts.h
>> (MASK_ZIHINTPAUSE, TARGET_ZIHINTPAUSE): New.
>> * config/riscv/riscv.md (riscv_pause): Make it only available when
>> the 'Zihintpause' extension is enabled. (riscv_pause_insn) New
>> "pause" implementation when the 'Zihintpause' extension is disabled.
>>
>> gcc/testsuite/ChangeLog:
>>
>> * gcc.target/riscv/builtin_pause.c: Removed.
>> * gcc.target/riscv/zihintpause.c:
>> New test when the 'Zihintpause' extension is enabled.
>> * gcc.target/riscv/zihintpause-noarch.c:
>> New test when the 'Zihintpause' extension is disabled.
> So I cleaned this up a bit per the list discussion and pushed the final
> result. Hopefully I didn't goof anything too badly ;-) The net is we
> emit "pause" or a suitable .insn based on TARGET_ZIHINTPAUSE.
>
> Jeff
Thanks! I had having a problem to type words through the keyboard for a
while and I appreciate doing that instead of me (your modifications were
mostly "I would do so too" ones).
Also, it seems that I will no longer need to ask you to remove leading
"[PATCH xxx]" (not just the commit title is not my intention, I worried
that you have been doing something inefficient [other than "git am"]).
Tsukasa
