Re: [PATCH] Preserve location in gimple_fold_builtin_memset

[Richard Biener <rguenther@suse.de>]

On Fri, 29 Oct 2021, Jakub Jelinek wrote:

> Hi!
> 
> As mentioned yesterday, gimple_fold_builtin_memset doesn't preserve
> locus which means e.g. the -Wstringop-overflow warnings are emitted as:
> In function 'test_max':
> cc1: warning: writing 1 byte into a region of size 0 [-Wstringop-overflow=]
> The function emits up to 2 new statements, but the latter (asgn) is added
> through gsi_replace and therefore the locus is copied over from the call.
> But store is emitted before the call and optionally the call removed
> afterwards, so locus needs to be copied over manually.
> 
> Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux, ok for
> trunk?

OK.

Thanks,
Richard.

> 2021-10-29  Jakub Jelinek  <jakub@redhat.com>
> 
> 	* gimple-fold.c (gimple_fold_builtin_memset): Copy over location from
> 	call to store.
> 
> 	* gcc.dg/Wstringop-overflow-62.c: Adjust expected diagnostics.
> 
> --- gcc/gimple-fold.c.jj	2021-10-12 09:36:57.728450483 +0200
> +++ gcc/gimple-fold.c	2021-10-28 12:42:07.638741783 +0200
> @@ -1505,6 +1505,7 @@ gimple_fold_builtin_memset (gimple_stmt_
>    var = fold_build2 (MEM_REF, etype, dest, build_int_cst (ptr_type_node, 0));
>    gimple *store = gimple_build_assign (var, build_int_cst_type (etype, cval));
>    gimple_move_vops (store, stmt);
> +  gimple_set_location (store, gimple_location (stmt));
>    gsi_insert_before (gsi, store, GSI_SAME_STMT);
>    if (gimple_call_lhs (stmt))
>      {
> --- gcc/testsuite/gcc.dg/Wstringop-overflow-62.c.jj	2021-10-28 12:24:21.909780099 +0200
> +++ gcc/testsuite/gcc.dg/Wstringop-overflow-62.c	2021-10-28 12:43:52.023273297 +0200
> @@ -223,7 +223,7 @@ void test_max (void)
>  
>      char *q = MAX (pi, pj);
>  
> -    memset (q, 0, 1);         // { dg-warning "writing 1 byte into a region of size 0 " "" { target *-*-* } 0 }
> +    memset (q, 0, 1);         // { dg-warning "writing 1 byte into a region of size 0 " }
>      memset (q, 0, 2);         // { dg-warning "writing 2 bytes into a region of size 0 " }
>    }
>  
> @@ -345,7 +345,7 @@ void test_max (void)
>         not reflected in the determaxed offset).  */
>      char *q = MAX (p1, p2);
>  
> -    memset (q, 0, 1);
> +    memset (q, 0, 1);         // { dg-warning "writing 1 byte into a region of size 0 " }
>    }
>  
>    {
> 
> 	Jakub
> 
> 

-- 
Richard Biener <rguenther@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)