re PR tree-optimization/79981 (Forwprop not working for __atomic_compare_exchange_n)

	PR tree-optimization/79981
	* tree-vrp.c (extract_range_basic): Handle IMAGPART_EXPR of
	ATOMIC_COMPARE_EXCHANGE ifn result.
	(stmt_interesting_for_vrp, vrp_visit_stmt): Handle
	IFN_ATOMIC_COMPARE_EXCHANGE.

From-SVN: r246054

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2837ddf..3342d77 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2017-03-10  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/79981
+       * tree-vrp.c (extract_range_basic): Handle IMAGPART_EXPR of
+       ATOMIC_COMPARE_EXCHANGE ifn result.
+       (stmt_interesting_for_vrp, vrp_visit_stmt): Handle
+       IFN_ATOMIC_COMPARE_EXCHANGE.
+
 2017-03-10  David Malcolm  <dmalcolm@redhat.com>
 
        PR driver/79875

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 6420041..2a4c764 100644 (file)
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -4107,7 +4107,7 @@ extract_range_basic (value_range *vr, gimple *stmt)
     }
   /* Handle extraction of the two results (result of arithmetics and
      a flag whether arithmetics overflowed) from {ADD,SUB,MUL}_OVERFLOW
-     internal function.  */
+     internal function.  Similarly from ATOMIC_COMPARE_EXCHANGE.  */
   else if (is_gimple_assign (stmt)
           && (gimple_assign_rhs_code (stmt) == REALPART_EXPR
               || gimple_assign_rhs_code (stmt) == IMAGPART_EXPR)
@@ -4132,6 +4132,16 @@ extract_range_basic (value_range *vr, gimple *stmt)
                case IFN_MUL_OVERFLOW:
                  subcode = MULT_EXPR;
                  break;
+               case IFN_ATOMIC_COMPARE_EXCHANGE:
+                 if (code == IMAGPART_EXPR)
+                   {
+                     /* This is the boolean return value whether compare and
+                        exchange changed anything or not.  */
+                     set_value_range (vr, VR_RANGE, build_int_cst (type, 0),
+                                      build_int_cst (type, 1), NULL);
+                     return;
+                   }
+                 break;
                default:
                  break;
                }
@@ -7283,6 +7293,7 @@ stmt_interesting_for_vrp (gimple *stmt)
          case IFN_ADD_OVERFLOW:
          case IFN_SUB_OVERFLOW:
          case IFN_MUL_OVERFLOW:
+         case IFN_ATOMIC_COMPARE_EXCHANGE:
            /* These internal calls return _Complex integer type,
               but are interesting to VRP nevertheless.  */
            if (lhs && TREE_CODE (lhs) == SSA_NAME)
@@ -8308,6 +8319,7 @@ vrp_visit_stmt (gimple *stmt, edge *taken_edge_p, tree *output_p)
       case IFN_ADD_OVERFLOW:
       case IFN_SUB_OVERFLOW:
       case IFN_MUL_OVERFLOW:
+      case IFN_ATOMIC_COMPARE_EXCHANGE:
        /* These internal calls return _Complex integer type,
           which VRP does not track, but the immediate uses
           thereof might be interesting.  */