[Bug middle-end/27336] delete null checks in callers to nonnull functions

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=27336

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org

--- Comment #11 from Richard Biener <rguenth at gcc dot gnu.org> ---
This is because of

static bool
infer_value_range (gimple *stmt, tree op, tree_code *comp_code_p, tree *val_p)
{
  *val_p = NULL_TREE;
  *comp_code_p = ERROR_MARK;

  /* Do not attempt to infer anything in names that flow through
     abnormal edges.  */
  if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
    return false;

  /* Similarly, don't infer anything from statements that may throw
     exceptions. ??? Relax this requirement?  */
  if (stmt_could_throw_p (stmt))
    return false;

thus it works with -fno-exceptions.  I think we can insert an assertion
anyway (on the non-EH edge).  Or at least relax the above to
stmt_could_throw_internal_p (stmt).  The following works for me.

Index: gcc/tree-vrp.c
===================================================================
--- gcc/tree-vrp.c      (revision 239653)
+++ gcc/tree-vrp.c      (working copy)
@@ -4782,11 +4760,6 @@ infer_value_range (gimple *stmt, tree op
   if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (op))
     return false;

-  /* Similarly, don't infer anything from statements that may throw
-     exceptions. ??? Relax this requirement?  */
-  if (stmt_could_throw_p (stmt))
-    return false;
-
   /* If STMT is the last statement of a basic block with no normal
      successors, there is no point inferring anything about any of its
      operands.  We would not be able to find a proper insertion point
@@ -4797,7 +4770,7 @@ infer_value_range (gimple *stmt, tree op
       edge e;

       FOR_EACH_EDGE (e, ei, gimple_bb (stmt)->succs)
-       if (!(e->flags & EDGE_ABNORMAL))
+       if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH)))
          break;
       if (e == NULL)
        return false;
@@ -6370,10 +6343,10 @@ process_assert_insertions_for (tree name

   /* If STMT must be the last statement in BB, we can only insert new
      assertions on the non-abnormal edge out of BB.  Note that since
-     STMT is not control flow, there may only be one non-abnormal edge
+     STMT is not control flow, there may only be one non-abnormal/eh edge
      out of BB.  */
   FOR_EACH_EDGE (e, ei, loc->bb->succs)
-    if (!(e->flags & EDGE_ABNORMAL))
+    if (!(e->flags & (EDGE_ABNORMAL|EDGE_EH)))
       {
        gsi_insert_on_edge (e, assert_stmt);
        return true;