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Re: [Qemu-devel] [PATCH 1/2] tcg: Restrict check_size_impl to multiples
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] tcg: Restrict check_size_impl to multiples of the line size |
Date: |
Fri, 06 Jul 2018 09:08:36 +0100 |
User-agent: |
mu4e 1.1.0; emacs 26.1.50 |
Richard Henderson <address@hidden> writes:
> Normally this is automatic in the size restrictions that are placed
> on vector sizes coming from the implementation. However, for the
> legitimate size tuple [oprsz=8, maxsz=32], we need to clear the final
> 24 bytes of the vector register. Without this check, do_dup selects
> TCG_TYPE_V128 and clears only 16 bytes.
>
> Signed-off-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
Tested-by: Alex Bennée <address@hidden>
> ---
> tcg/tcg-op-gvec.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/tcg/tcg-op-gvec.c b/tcg/tcg-op-gvec.c
> index 22db1590d5..61c25f5784 100644
> --- a/tcg/tcg-op-gvec.c
> +++ b/tcg/tcg-op-gvec.c
> @@ -287,8 +287,11 @@ void tcg_gen_gvec_4_ptr(uint32_t dofs, uint32_t aofs,
> uint32_t bofs,
> in units of LNSZ. This limits the expansion of inline code. */
> static inline bool check_size_impl(uint32_t oprsz, uint32_t lnsz)
> {
> - uint32_t lnct = oprsz / lnsz;
> - return lnct >= 1 && lnct <= MAX_UNROLL;
> + if (oprsz % lnsz == 0) {
> + uint32_t lnct = oprsz / lnsz;
> + return lnct >= 1 && lnct <= MAX_UNROLL;
> + }
> + return false;
> }
>
> static void expand_clr(uint32_t dofs, uint32_t maxsz);
--
Alex Bennée