[PATCH] Silence some -Wnarrowing errors

[PATCH] Silence some -Wnarrowing errors

[Eric Gallager]

[-- Attachment #1: Type: text/plain, Size: 1013 bytes --]

I tried turning -Wnarrowing back on earlier this year, but
unfortunately it didn't work due to triggering a bunch of new errors.
This patch silences at least some of them, but there will still be
more left even after applying it. (When compiling with clang,
technically the warning flag is -Wc++11-narrowing, but it's pretty
much the same thing as gcc's -Wnarrowing, albeit with fixit hints,
which I made use of to insert the casts here.)

gcc/ChangeLog:

    * ipa-modref.cc (modref_lattice::add_escape_point): Use a
static_cast to silence -Wnarrowing.
    (modref_eaf_analysis::record_escape_points): Likewise.
    (update_escape_summary_1): Likewise.
    * rtl-ssa/changes.cc (function_info::temp_access_array): Likewise.
    * rtl-ssa/member-fns.inl: Likewise.
    * tree-ssa-structalias.cc (push_fields_onto_fieldstack): Likewise.
    * tree-vect-slp.cc (vect_prologue_cost_for_slp): Likewise.
    * tree-vect-stmts.cc (vect_truncate_gather_scatter_offset): Likewise.
    (vectorizable_operation): Likewise.

[-- Attachment #2: patch-Wnarrowing.diff --]
[-- Type: application/octet-stream, Size: 4708 bytes --]

diff --git a/gcc/ipa-modref.cc b/gcc/ipa-modref.cc
index 0d9abacf0a6..4183fed73c7 100644
--- a/gcc/ipa-modref.cc
+++ b/gcc/ipa-modref.cc
@@ -2119,7 +2119,7 @@ modref_lattice::add_escape_point (gcall *call, int arg, int min_flags,
       merge (0);
       return true;
     }
-  escape_point new_ep = {call, arg, min_flags, direct};
+  escape_point new_ep = {call, arg, static_cast<eaf_flags_t>(min_flags), direct};
   escape_points.safe_push (new_ep);
   return true;
 }
@@ -2880,7 +2880,8 @@ modref_eaf_analysis::record_escape_points (tree name, int parm_index, int flags)
 	if ((ep->min_flags & flags) != flags)
 	  {
 	    cgraph_edge *e = node->get_edge (ep->call);
-	    struct escape_entry ee = {parm_index, ep->arg,
+	    struct escape_entry ee = {parm_index,
+				      static_cast<unsigned int>(ep->arg),
 				      ep->min_flags, ep->direct};
 
 	    escape_summaries->get_create (e)->esc.safe_push (ee);
@@ -4350,8 +4351,8 @@ update_escape_summary_1 (cgraph_edge *e,
 	  if (ee->direct && !em->direct)
 	    min_flags = deref_flags (min_flags, ignore_stores);
 	  struct escape_entry entry = {em->parm_index, ee->arg,
-				       min_flags,
-				       ee->direct & em->direct};
+				       static_cast<eaf_flags_t>(min_flags),
+				       static_cast<bool>(ee->direct & em->direct)};
 	  sum->esc.safe_push (entry);
 	}
     }
diff --git a/gcc/rtl-ssa/changes.cc b/gcc/rtl-ssa/changes.cc
index 298358ed6d4..8b54714a4cc 100644
--- a/gcc/rtl-ssa/changes.cc
+++ b/gcc/rtl-ssa/changes.cc
@@ -90,7 +90,7 @@ function_info::temp_access_array (access_array accesses)
   gcc_assert (obstack_object_size (&m_temp_obstack) == 0);
   obstack_grow (&m_temp_obstack, accesses.begin (), accesses.size_bytes ());
   return { static_cast<access_info **> (obstack_finish (&m_temp_obstack)),
-	   accesses.size () };
+	   static_cast<unsigned int>(accesses.size ()) };
 }
 
 // See the comment above the declaration.
diff --git a/gcc/rtl-ssa/member-fns.inl b/gcc/rtl-ssa/member-fns.inl
index 25a8750aefa..f7b91bc3c6f 100644
--- a/gcc/rtl-ssa/member-fns.inl
+++ b/gcc/rtl-ssa/member-fns.inl
@@ -47,7 +47,7 @@ access_array_builder::finish ()
 
   auto **base = static_cast<access_info **> (obstack_finish (m_obstack));
   keep ();
-  return { base, num_accesses };
+  return { base, static_cast<unsigned int>(num_accesses) };
 }
 
 inline bool
diff --git a/gcc/tree-ssa-structalias.cc b/gcc/tree-ssa-structalias.cc
index dcf13d939bd..e85a36eda3d 100644
--- a/gcc/tree-ssa-structalias.cc
+++ b/gcc/tree-ssa-structalias.cc
@@ -5885,7 +5885,8 @@ push_fields_onto_fieldstack (tree type, vec<fieldoff_s> *fieldstack,
 		&& offset + foff != 0)
 	      {
 		fieldoff_s e
-		  = {0, offset + foff, false, false, true, false, NULL_TREE};
+		  = {0, static_cast<unsigned long long>(offset + foff), false,
+		     false, true, false, NULL_TREE};
 		pair = fieldstack->safe_push (e);
 	      }
 
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index e54414f6bef..9cf06aa4218 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -6055,7 +6055,8 @@ vect_prologue_cost_for_slp (slp_tree node,
       nelt_limit = const_nunits;
       hash_set<vect_scalar_ops_slice_hash> vector_ops;
       for (unsigned int i = 0; i < SLP_TREE_NUMBER_OF_VEC_STMTS (node); ++i)
-	if (!vector_ops.add ({ ops, i * const_nunits, const_nunits }))
+	if (!vector_ops.add ({ ops, static_cast<unsigned int>(i * const_nunits),
+	                       static_cast<unsigned int>(const_nunits) }))
 	  starts.quick_push (i * const_nunits);
     }
   else
diff --git a/gcc/tree-vect-stmts.cc b/gcc/tree-vect-stmts.cc
index 5485da58b38..31453665aa9 100644
--- a/gcc/tree-vect-stmts.cc
+++ b/gcc/tree-vect-stmts.cc
@@ -1911,7 +1911,7 @@ vect_truncate_gather_scatter_offset (stmt_vec_info stmt_info,
     count = max_iters.to_shwi ();
 
   /* Try scales of 1 and the element size.  */
-  int scales[] = { 1, vect_get_scalar_dr_size (dr_info) };
+  int scales[] = { 1, static_cast<int>(vect_get_scalar_dr_size (dr_info)) };
   wi::overflow_type overflow = wi::OVF_NONE;
   for (int i = 0; i < 2; ++i)
     {
@@ -6476,7 +6476,7 @@ vectorizable_operation (vec_info *vinfo,
 	      && VECTOR_BOOLEAN_TYPE_P (vectype))
 	    {
 	      if (loop_vinfo->scalar_cond_masked_set.contains ({ op0,
-								 ncopies}))
+								 static_cast<unsigned int>(ncopies)}))
 		{
 		  mask = vect_get_loop_mask (gsi, masks, vec_num * ncopies,
 					     vectype, i);
@@ -6486,7 +6486,7 @@ vectorizable_operation (vec_info *vinfo,
 		}
 
 	      if (loop_vinfo->scalar_cond_masked_set.contains ({ op1,
-								 ncopies }))
+								 static_cast<unsigned int>(ncopies) }))
 		{
 		  mask = vect_get_loop_mask (gsi, masks, vec_num * ncopies,
 					     vectype, i);

Re: [PATCH] Silence some -Wnarrowing errors

[Jeff Law]

On 12/2/22 00:26, Eric Gallager via Gcc-patches wrote:
> I tried turning -Wnarrowing back on earlier this year, but
> unfortunately it didn't work due to triggering a bunch of new errors.
> This patch silences at least some of them, but there will still be
> more left even after applying it. (When compiling with clang,
> technically the warning flag is -Wc++11-narrowing, but it's pretty
> much the same thing as gcc's -Wnarrowing, albeit with fixit hints,
> which I made use of to insert the casts here.)
> 
> gcc/ChangeLog:
> 
>      * ipa-modref.cc (modref_lattice::add_escape_point): Use a
> static_cast to silence -Wnarrowing.
>      (modref_eaf_analysis::record_escape_points): Likewise.
>      (update_escape_summary_1): Likewise.
>      * rtl-ssa/changes.cc (function_info::temp_access_array): Likewise.
>      * rtl-ssa/member-fns.inl: Likewise.
>      * tree-ssa-structalias.cc (push_fields_onto_fieldstack): Likewise.
>      * tree-vect-slp.cc (vect_prologue_cost_for_slp): Likewise.
>      * tree-vect-stmts.cc (vect_truncate_gather_scatter_offset): Likewise.
>      (vectorizable_operation): Likewise.
It's potentially more invasive change, but I'd lean towards trying to 
fix the API to pass the right types rather than using static_cast.

jeff

Re: [PATCH] Silence some -Wnarrowing errors

[Jeff Law]

On 12/2/22 00:26, Eric Gallager via Gcc-patches wrote:
> I tried turning -Wnarrowing back on earlier this year, but
> unfortunately it didn't work due to triggering a bunch of new errors.
> This patch silences at least some of them, but there will still be
> more left even after applying it. (When compiling with clang,
> technically the warning flag is -Wc++11-narrowing, but it's pretty
> much the same thing as gcc's -Wnarrowing, albeit with fixit hints,
> which I made use of to insert the casts here.)
> 
> gcc/ChangeLog:
> 
>      * ipa-modref.cc (modref_lattice::add_escape_point): Use a
> static_cast to silence -Wnarrowing.
>      (modref_eaf_analysis::record_escape_points): Likewise.
>      (update_escape_summary_1): Likewise.
>      * rtl-ssa/changes.cc (function_info::temp_access_array): Likewise.
>      * rtl-ssa/member-fns.inl: Likewise.
>      * tree-ssa-structalias.cc (push_fields_onto_fieldstack): Likewise.
>      * tree-vect-slp.cc (vect_prologue_cost_for_slp): Likewise.
>      * tree-vect-stmts.cc (vect_truncate_gather_scatter_offset): Likewise.
>      (vectorizable_operation): Likewise.
Would it make sense to instead fix the APIs so that instead of passing 
an "int" they instead pass a suitable enum type?

So for example, modref_lattice::add_escape_point passes "min_flags" as 
an int.  It probably should be an eaf_flags_t.  That may (of course) 
bleed out into other places.  So I'd probably suggest you pick one case 
such as this add_escape_point, make it's API change, fix the fallout and 
submit that as a patch.

Then proceed to the next case where you added a static_cast and do the 
same thing there.

In addition to fixing the warnings, this should make the codebase 
cleaner and catch more errors using the typesystem.

jeff