Re: [PATCH] LoongArch: Use fcmp.caf.s instead of movgr2cf for zeroing a fcc
在 2023/10/17 下午10:24, WANG Xuerui 写道: On 10/17/23 22:06, Xi Ruoyao wrote: During the review of a LLVM change [1], on LA464 we found that zeroing "an" LLVM change (because the word LLVM is pronounced letter-by-letter) a fcc with fcmp.caf.s is much faster than a movgr2cf from $r0. Similarly, "an" fcc [1]: https://github.com/llvm/llvm-project/pull/69300 gcc/ChangeLog: * config/loongarch/loongarch.md (movfcc): Use fcmp.caf.s for zeroing a fcc. --- Bootstrapped and regtested on loongarch64-linux-gnu. Ok for trunk? Ok! Thanks. gcc/config/loongarch/loongarch.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md index 68897799505..743e75907a6 100644 --- a/gcc/config/loongarch/loongarch.md +++ b/gcc/config/loongarch/loongarch.md @@ -2151,7 +2151,7 @@ (define_insn "movfcc" [(set (match_operand:FCC 0 "register_operand" "=z") (const_int 0))] "" - "movgr2cf\t%0,$r0") + "fcmp.caf.s\t%0,$f0,$f0") ;; Conditional move instructions. Trivial enough, so this LGTM apart from the grammatical nits. (Whoever pushing this patch could simply amend it themselves so maybe there's no need for a v2.) Thanks! \
Re: [PATCH] LoongArch: Use fcmp.caf.s instead of movgr2cf for zeroing a fcc
On 10/17/23 22:06, Xi Ruoyao wrote: During the review of a LLVM change [1], on LA464 we found that zeroing "an" LLVM change (because the word LLVM is pronounced letter-by-letter) a fcc with fcmp.caf.s is much faster than a movgr2cf from $r0. Similarly, "an" fcc [1]: https://github.com/llvm/llvm-project/pull/69300 gcc/ChangeLog: * config/loongarch/loongarch.md (movfcc): Use fcmp.caf.s for zeroing a fcc. --- Bootstrapped and regtested on loongarch64-linux-gnu. Ok for trunk? gcc/config/loongarch/loongarch.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md index 68897799505..743e75907a6 100644 --- a/gcc/config/loongarch/loongarch.md +++ b/gcc/config/loongarch/loongarch.md @@ -2151,7 +2151,7 @@ (define_insn "movfcc" [(set (match_operand:FCC 0 "register_operand" "=z") (const_int 0))] "" - "movgr2cf\t%0,$r0") + "fcmp.caf.s\t%0,$f0,$f0") ;; Conditional move instructions. Trivial enough, so this LGTM apart from the grammatical nits. (Whoever pushing this patch could simply amend it themselves so maybe there's no need for a v2.) Thanks!
