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! \
