[Bug lto/83338] [8 Regression] SPEC CPU2017 510.parest_r ICE

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83338

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This works for me, but I'll leave testcase and testing for tomorrow.
--- gcc/tree-vect-stmts.c.jj    2017-12-08 12:21:58.000000000 +0100
+++ gcc/tree-vect-stmts.c       2017-12-09 00:55:17.614147824 +0100
@@ -5226,7 +5226,7 @@ vectorizable_operation (gimple *stmt, gi
   stmt_vec_info stmt_info = vinfo_for_stmt (stmt);
   tree vectype;
   loop_vec_info loop_vinfo = STMT_VINFO_LOOP_VINFO (stmt_info);
-  enum tree_code code;
+  enum tree_code code, orig_code;
   machine_mode vec_mode;
   tree new_temp;
   int op_type;
@@ -5264,7 +5264,7 @@ vectorizable_operation (gimple *stmt, gi
   if (TREE_CODE (gimple_assign_lhs (stmt)) != SSA_NAME)
     return false;

-  code = gimple_assign_rhs_code (stmt);
+  orig_code = code = gimple_assign_rhs_code (stmt);

   /* For pointer addition and subtraction, we should use the normal
      plus and minus for the vector operation.  */
@@ -5455,6 +5455,14 @@ vectorizable_operation (gimple *stmt, gi
   /* Handle def.  */
   vec_dest = vect_create_destination_var (scalar_dest, vectype);

+  /* POINTER_DIFF_EXPR has pointer arguments which are vectorized as
+     vectors with unsigned elements, but the result is signed.  So, we
+     need to compute the MINUS_EXPR into vectype temporary and
+     VIEW_CONVERT_EXPR it into the final vectype_out result.  */
+  tree vec_cvt_dest = NULL_TREE;
+  if (orig_code == POINTER_DIFF_EXPR)
+    vec_cvt_dest = vect_create_destination_var (scalar_dest, vectype_out);
+
   /* In case the vectorization factor (VF) is bigger than the number
      of elements that we can fit in a vectype (nunits), we have to generate
      more than one vector stmt - i.e - we need to "unroll" the
@@ -5546,6 +5554,15 @@ vectorizable_operation (gimple *stmt, gi
          new_temp = make_ssa_name (vec_dest, new_stmt);
          gimple_assign_set_lhs (new_stmt, new_temp);
          vect_finish_stmt_generation (stmt, new_stmt, gsi);
+         if (vec_cvt_dest)
+           {
+             new_temp = build1 (VIEW_CONVERT_EXPR, vectype_out, new_temp);
+             new_stmt = gimple_build_assign (vec_cvt_dest, VIEW_CONVERT_EXPR,
+                                             new_temp);
+             new_temp = make_ssa_name (vec_cvt_dest, new_stmt);
+             gimple_assign_set_lhs (new_stmt, new_temp);
+             vect_finish_stmt_generation (stmt, new_stmt, gsi);
+           }
           if (slp_node)
            SLP_TREE_VEC_STMTS (slp_node).quick_push (new_stmt);
         }