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Re: [Qemu-devel] [PATCH 2/2] target/arm: Fix do_predset for large VL
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH 2/2] target/arm: Fix do_predset for large VL |
Date: |
Fri, 06 Jul 2018 09:14:13 +0100 |
User-agent: |
mu4e 1.1.0; emacs 26.1.50 |
Richard Henderson <address@hidden> writes:
> Use MAKE_64BIT_MASK instead of open-coding. Remove an odd
> vector size check that is unlikely to be more profitable
> than 3 64-bit integer stores. Correct the iteration for WORD
> to avoid writing too much data.
>
> Fixes RISU tests of PTRUE for VL 256.
>
> Signed-off-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
Tested-by: Alex Bennée <address@hidden>
> ---
> target/arm/translate-sve.c | 10 ++--------
> 1 file changed, 2 insertions(+), 8 deletions(-)
>
> diff --git a/target/arm/translate-sve.c b/target/arm/translate-sve.c
> index d41f1155f9..374051cd20 100644
> --- a/target/arm/translate-sve.c
> +++ b/target/arm/translate-sve.c
> @@ -1438,7 +1438,7 @@ static bool do_predset(DisasContext *s, int esz, int
> rd, int pat, bool setflag)
> setsz = numelem << esz;
> lastword = word = pred_esz_masks[esz];
> if (setsz % 64) {
> - lastword &= ~(-1ull << (setsz % 64));
> + lastword &= MAKE_64BIT_MASK(0, setsz % 64);
> }
> }
>
> @@ -1457,19 +1457,13 @@ static bool do_predset(DisasContext *s, int esz, int
> rd, int pat, bool setflag)
> tcg_gen_gvec_dup64i(ofs, oprsz, maxsz, word);
> goto done;
> }
> - if (oprsz * 8 == setsz + 8) {
> - tcg_gen_gvec_dup64i(ofs, oprsz, maxsz, word);
> - tcg_gen_movi_i64(t, 0);
> - tcg_gen_st_i64(t, cpu_env, ofs + oprsz - 8);
> - goto done;
> - }
> }
>
> setsz /= 8;
> fullsz /= 8;
>
> tcg_gen_movi_i64(t, word);
> - for (i = 0; i < setsz; i += 8) {
> + for (i = 0; i < QEMU_ALIGN_DOWN(setsz, 8); i += 8) {
> tcg_gen_st_i64(t, cpu_env, ofs + i);
> }
> if (lastword != word) {
--
Alex Bennée