From: Richard Biener <richard.guenther@gmail.com>
To: Andrew Pinski <apinski@marvell.com>
Cc: gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] Fix PR 106900: array-bounds warning inside simplify_builtin_call
Date: Wed, 17 May 2023 08:29:07 +0200 [thread overview]
Message-ID: <CAFiYyc0wfVbCrGoQhPRXoCTvcLZZSQ+swuGXTm1G_GVcHF8pRA@mail.gmail.com> (raw)
In-Reply-To: <20230517005256.1718424-1-apinski@marvell.com>
On Wed, May 17, 2023 at 2:54 AM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> The problem here is that VRP cannot figure out isize could not be 0
> due to using integer_zerop. This patch removes the use of integer_zerop
> and instead checks for 0 directly after converting the tree to
> an unsigned HOST_WIDE_INT. This allows VRP to figure out isize is not 0
> and `isize - 1` will always be >= 0.
>
> This patch is just to avoid the warning that GCC could produce sometimes
> and does not change any code generation or even VRP.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
OK.
Richard.
> gcc/ChangeLog:
>
> * tree-ssa-forwprop.cc (simplify_builtin_call): Check
> against 0 instead of calling integer_zerop.
> ---
> gcc/tree-ssa-forwprop.cc | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/tree-ssa-forwprop.cc b/gcc/tree-ssa-forwprop.cc
> index 06f19868ade..0326e6733e8 100644
> --- a/gcc/tree-ssa-forwprop.cc
> +++ b/gcc/tree-ssa-forwprop.cc
> @@ -1231,14 +1231,14 @@ simplify_builtin_call (gimple_stmt_iterator *gsi_p, tree callee2)
> tree size = gimple_call_arg (stmt2, 2);
> /* Size must be a constant which is <= UNITS_PER_WORD and
> <= the string length. */
> - if (TREE_CODE (size) != INTEGER_CST || integer_zerop (size))
> + if (TREE_CODE (size) != INTEGER_CST)
> break;
>
> if (!tree_fits_uhwi_p (size))
> break;
>
> unsigned HOST_WIDE_INT sz = tree_to_uhwi (size);
> - if (sz > UNITS_PER_WORD || sz >= slen)
> + if (sz == 0 || sz > UNITS_PER_WORD || sz >= slen)
> break;
>
> tree ch = gimple_call_arg (stmt2, 1);
> --
> 2.31.1
>
prev parent reply other threads:[~2023-05-17 6:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-17 0:52 Andrew Pinski
2023-05-17 6:29 ` Richard Biener [this message]
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