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* configure.ac: Update minimum MPC version to 0.8.
[pf3gnuchains/gcc-fork.git] / gcc / tree-ssa-pre.c
index 6ae05b5..a3e7ad8 100644 (file)
@@ -1156,7 +1156,7 @@ fully_constant_expression (pre_expr e)
            }
          case tcc_reference:
            if (nary->opcode != REALPART_EXPR
-               && nary->opcode != IMAGPART_EXPR 
+               && nary->opcode != IMAGPART_EXPR
                && nary->opcode != VIEW_CONVERT_EXPR)
              return e;
            /* Fallthrough.  */
@@ -1243,43 +1243,74 @@ do_unary:
 }
 
 /* Translate the VUSE backwards through phi nodes in PHIBLOCK, so that
-   it has the value it would have in BLOCK.  */
+   it has the value it would have in BLOCK.  Set *SAME_VALID to true
+   in case the new vuse doesn't change the value id of the OPERANDS.  */
 
 static tree
 translate_vuse_through_block (VEC (vn_reference_op_s, heap) *operands,
                              alias_set_type set, tree type, tree vuse,
                              basic_block phiblock,
-                             basic_block block)
+                             basic_block block, bool *same_valid)
 {
   gimple phi = SSA_NAME_DEF_STMT (vuse);
   ao_ref ref;
+  edge e = NULL;
+  bool use_oracle;
+
+  *same_valid = true;
 
   if (gimple_bb (phi) != phiblock)
     return vuse;
 
-  if (gimple_code (phi) == GIMPLE_PHI)
-    {
-      edge e = find_edge (block, phiblock);
-      return PHI_ARG_DEF (phi, e->dest_idx);
-    }
-
-  if (!ao_ref_init_from_vn_reference (&ref, set, type, operands))
-    return NULL_TREE;
+  use_oracle = ao_ref_init_from_vn_reference (&ref, set, type, operands);
 
   /* Use the alias-oracle to find either the PHI node in this block,
      the first VUSE used in this block that is equivalent to vuse or
      the first VUSE which definition in this block kills the value.  */
-  while (!stmt_may_clobber_ref_p_1 (phi, &ref))
+  if (gimple_code (phi) == GIMPLE_PHI)
+    e = find_edge (block, phiblock);
+  else if (use_oracle)
+    while (!stmt_may_clobber_ref_p_1 (phi, &ref))
+      {
+       vuse = gimple_vuse (phi);
+       phi = SSA_NAME_DEF_STMT (vuse);
+       if (gimple_bb (phi) != phiblock)
+         return vuse;
+       if (gimple_code (phi) == GIMPLE_PHI)
+         {
+           e = find_edge (block, phiblock);
+           break;
+         }
+      }
+  else
+    return NULL_TREE;
+
+  if (e)
     {
-      vuse = gimple_vuse (phi);
-      phi = SSA_NAME_DEF_STMT (vuse);
-      if (gimple_bb (phi) != phiblock)
-       return vuse;
-      if (gimple_code (phi) == GIMPLE_PHI)
+      if (use_oracle)
+       {
+         bitmap visited = NULL;
+         /* Try to find a vuse that dominates this phi node by skipping
+            non-clobbering statements.  */
+         vuse = get_continuation_for_phi (phi, &ref, &visited);
+         if (visited)
+           BITMAP_FREE (visited);
+       }
+      else
+       vuse = NULL_TREE;
+      if (!vuse)
        {
-         edge e = find_edge (block, phiblock);
-         return PHI_ARG_DEF (phi, e->dest_idx);
+         /* If we didn't find any, the value ID can't stay the same,
+            but return the translated vuse.  */
+         *same_valid = false;
+         vuse = PHI_ARG_DEF (phi, e->dest_idx);
        }
+      /* ??? We would like to return vuse here as this is the canonical
+         upmost vdef that this reference is associated with.  But during
+        insertion of the references into the hash tables we only ever
+        directly insert with their direct gimple_vuse, hence returning
+        something else would make us not find the other expression.  */
+      return PHI_ARG_DEF (phi, e->dest_idx);
     }
 
   return NULL_TREE;
@@ -1541,7 +1572,7 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
        tree vuse = ref->vuse;
        tree newvuse = vuse;
        VEC (vn_reference_op_s, heap) *newoperands = NULL;
-       bool changed = false;
+       bool changed = false, same_valid = true;
        unsigned int i, j;
        vn_reference_op_t operand;
        vn_reference_t newref;
@@ -1647,16 +1678,16 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
          {
            newvuse = translate_vuse_through_block (newoperands,
                                                    ref->set, ref->type,
-                                                   vuse, phiblock, pred);
+                                                   vuse, phiblock, pred,
+                                                   &same_valid);
            if (newvuse == NULL_TREE)
              {
                VEC_free (vn_reference_op_s, heap, newoperands);
                return NULL;
              }
          }
-       changed |= newvuse != vuse;
 
-       if (changed)
+       if (changed || newvuse != vuse)
          {
            unsigned int new_val_id;
            pre_expr constant;
@@ -1690,9 +1721,15 @@ phi_translate_1 (pre_expr expr, bitmap_set_t set1, bitmap_set_t set2,
              }
            else
              {
-               new_val_id = get_next_value_id ();
-               VEC_safe_grow_cleared (bitmap_set_t, heap, value_expressions,
-                                      get_max_value_id() + 1);
+               if (changed || !same_valid)
+                 {
+                   new_val_id = get_next_value_id ();
+                   VEC_safe_grow_cleared (bitmap_set_t, heap,
+                                          value_expressions,
+                                          get_max_value_id() + 1);
+                 }
+               else
+                 new_val_id = ref->value_id;
                newref = vn_reference_insert_pieces (newvuse, ref->set,
                                                     ref->type,
                                                     newoperands,
@@ -2961,7 +2998,7 @@ create_expression_by_pieces (basic_block block, pre_expr expr,
                genop2 = fold_convert (sizetype, genop2);
              else
                genop2 = fold_convert (TREE_TYPE (nary->op[1]), genop2);
-             
+
              folded = fold_build2 (nary->opcode, nary->type,
                                    genop1, genop2);
            }
@@ -3220,7 +3257,7 @@ insert_into_preds_of_block (basic_block block, unsigned int exprnum,
          if (!useless_type_conversion_p (type, TREE_TYPE (constant)))
            {
              tree builtexpr = fold_convert (type, constant);
-             if (!is_gimple_min_invariant (builtexpr)) 
+             if (!is_gimple_min_invariant (builtexpr))
                {
                  tree forcedexpr = force_gimple_operand (builtexpr,
                                                          &stmts, true,
@@ -3914,7 +3951,7 @@ compute_avail (void)
 
                      vn_reference_lookup (gimple_assign_rhs1 (stmt),
                                           gimple_vuse (stmt),
-                                          false, &ref);
+                                          true, &ref);
                      if (!ref)
                        continue;
 
@@ -4425,8 +4462,10 @@ remove_dead_inserted_code (void)
          if (gimple_code (t) == GIMPLE_PHI)
            remove_phi_node (&gsi, true);
          else
-           gsi_remove (&gsi, true);
-         release_defs (t);
+           {
+             gsi_remove (&gsi, true);
+             release_defs (t);
+           }
        }
     }
   VEC_free (gimple, heap, worklist);
@@ -4550,7 +4589,7 @@ execute_pre (bool do_fre)
          remove_dead_inserted_code ();
          loop_optimizer_finalize ();
        }
-      
+
       return 0;
     }
   init_pre (do_fre);