[gcc r12-4784] gimple-fold: Preserve location in gimple_fold_builtin_memset

[gcc r12-4784] gimple-fold: Preserve location in gimple_fold_builtin_memset

[Jakub Jelinek]

https://gcc.gnu.org/g:f1ba6a819de6f4aacf9d69725f64496d20edd5a1

commit r12-4784-gf1ba6a819de6f4aacf9d69725f64496d20edd5a1
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Oct 29 10:20:29 2021 +0200

    gimple-fold: Preserve location in gimple_fold_builtin_memset
    
    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.
    
    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.

Diff:
---
 gcc/gimple-fold.c                            | 1 +
 gcc/testsuite/gcc.dg/Wstringop-overflow-62.c | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 7fcfef41f72..6e25a7c05db 100644
--- a/gcc/gimple-fold.c
+++ b/gcc/gimple-fold.c
@@ -1505,6 +1505,7 @@ gimple_fold_builtin_memset (gimple_stmt_iterator *gsi, tree c, tree len)
   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))
     {
diff --git a/gcc/testsuite/gcc.dg/Wstringop-overflow-62.c b/gcc/testsuite/gcc.dg/Wstringop-overflow-62.c
index e39ab2fb45a..ea19aa85905 100644
--- a/gcc/testsuite/gcc.dg/Wstringop-overflow-62.c
+++ b/gcc/testsuite/gcc.dg/Wstringop-overflow-62.c
@@ -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 " }
   }
 
   {