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 --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 7fcfef41f7229f92830201c350cf82b861cbbcac..6e25a7c05dbe57602dab540f68c423d1d20df204 100644 (file)
--- 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 e39ab2fb45a3a5f797725f9ae4032bb41bfe28d6..ea19aa85905b79412c868ae7dd437344841fdf96 100644 (file)
--- 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 " }
   }
 
   {