* [PATCH] Fix PR 106900: array-bounds warning inside simplify_builtin_call
@ 2023-05-17 0:52 Andrew Pinski
2023-05-17 6:29 ` Richard Biener
0 siblings, 1 reply; 2+ messages in thread
From: Andrew Pinski @ 2023-05-17 0:52 UTC (permalink / raw)
To: gcc-patches; +Cc: Andrew Pinski
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.
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
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] Fix PR 106900: array-bounds warning inside simplify_builtin_call
2023-05-17 0:52 [PATCH] Fix PR 106900: array-bounds warning inside simplify_builtin_call Andrew Pinski
@ 2023-05-17 6:29 ` Richard Biener
0 siblings, 0 replies; 2+ messages in thread
From: Richard Biener @ 2023-05-17 6:29 UTC (permalink / raw)
To: Andrew Pinski; +Cc: gcc-patches
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
>
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