re PR tree-optimization/91403 (GCC fails with ICE.)

2019-08-19  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/91403
	* tree-scalar-evolution.c (follow_ssa_edge_binary): Inline
	cases we can handle with tail-recursion...
	(follow_ssa_edge_expr): ... here.  Do so.

From-SVN: r274672

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fb32bb1c308ac5fbad7901889e569ef4849c0a6a..ccc63c24a711d3d9b6c75b7a65f9ec3b2ccc8282 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2019-08-19  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/91403
+       * tree-scalar-evolution.c (follow_ssa_edge_binary): Inline
+       cases we can handle with tail-recursion...
+       (follow_ssa_edge_expr): ... here.  Do so.
+
 2019-08-19  Kito Cheng  <kito.cheng@sifive.com>
 
        PR target/91441

diff --git a/gcc/tree-scalar-evolution.c b/gcc/tree-scalar-evolution.c
index 82c4c5b931b59606f7de493d05c80952fc0d494d..50b2700834ec6514e0cdf78a2858f4ade1f1a024 100644 (file)
--- a/gcc/tree-scalar-evolution.c
+++ b/gcc/tree-scalar-evolution.c
@@ -925,32 +925,11 @@ follow_ssa_edge_binary (class loop *loop, gimple *at_stmt,
                  res = follow_ssa_edge_expr
                    (loop, at_stmt, rhs1, halting_phi,
                     evolution_of_loop, limit);
-                 if (res == t_true)
-                   ;
-                 else if (res == t_dont_know)
-                   *evolution_of_loop = chrec_dont_know;
                }
-
-             else if (res == t_dont_know)
-               *evolution_of_loop = chrec_dont_know;
            }
 
          else
-           {
-             /* Match an assignment under the form:
-                "a = b + ...".  */
-             *evolution_of_loop = add_to_evolution
-                 (loop->num, chrec_convert (type, *evolution_of_loop,
-                                            at_stmt),
-                  code, rhs1, at_stmt);
-             res = follow_ssa_edge_expr
-               (loop, at_stmt, rhs0, halting_phi,
-                evolution_of_loop, limit);
-             if (res == t_true)
-               ;       
-             else if (res == t_dont_know)
-               *evolution_of_loop = chrec_dont_know;
-           }
+           gcc_unreachable ();  /* Handled in caller.  */
        }
 
       else if (TREE_CODE (rhs1) == SSA_NAME)
@@ -964,10 +943,6 @@ follow_ssa_edge_binary (class loop *loop, gimple *at_stmt,
          res = follow_ssa_edge_expr
            (loop, at_stmt, rhs1, halting_phi,
             evolution_of_loop, limit);
-         if (res == t_true)
-           ;
-         else if (res == t_dont_know)
-           *evolution_of_loop = chrec_dont_know;
        }
 
       else
@@ -980,26 +955,7 @@ follow_ssa_edge_binary (class loop *loop, gimple *at_stmt,
     case MINUS_EXPR:
       /* This case is under the form "opnd0 = rhs0 - rhs1".  */
       if (TREE_CODE (rhs0) == SSA_NAME)
-       {
-         /* Match an assignment under the form:
-            "a = b - ...".  */
-
-         /* We want only assignments of form "name - name" contribute to
-            LIMIT, as the other cases do not necessarily contribute to
-            the complexity of the expression.  */
-         if (TREE_CODE (rhs1) == SSA_NAME)
-           limit++;
-
-         *evolution_of_loop = add_to_evolution
-             (loop->num, chrec_convert (type, *evolution_of_loop, at_stmt),
-              MINUS_EXPR, rhs1, at_stmt);
-         res = follow_ssa_edge_expr (loop, at_stmt, rhs0, halting_phi,
-                                     evolution_of_loop, limit);
-         if (res == t_true)
-           ;
-         else if (res == t_dont_know)
-           *evolution_of_loop = chrec_dont_know;
-       }
+       gcc_unreachable (); /* Handled in caller.  */
       else
        /* Otherwise, match an assignment under the form:
           "a = ... - ...".  */
@@ -1184,6 +1140,7 @@ follow_ssa_edge_expr (class loop *loop, gimple *at_stmt, tree expr,
   /* For SSA_NAME look at the definition statement, handling
      PHI nodes and otherwise expand appropriately for the expression
      handling below.  */
+tail_recurse:
   if (TREE_CODE (expr) == SSA_NAME)
     {
       gimple *def = SSA_NAME_DEF_STMT (expr);
@@ -1193,7 +1150,10 @@ follow_ssa_edge_expr (class loop *loop, gimple *at_stmt, tree expr,
 
       /* Give up if the path is longer than the MAX that we allow.  */
       if (limit > PARAM_VALUE (PARAM_SCEV_MAX_EXPR_COMPLEXITY))
-       return t_dont_know;
+       {
+         *evolution_of_loop = chrec_dont_know;
+         return t_dont_know;
+       }
 
       if (gphi *phi = dyn_cast <gphi *>(def))
        {
@@ -1303,14 +1263,28 @@ follow_ssa_edge_expr (class loop *loop, gimple *at_stmt, tree expr,
       /* This case is under the form "rhs0 +- rhs1".  */
       STRIP_USELESS_TYPE_CONVERSION (rhs0);
       STRIP_USELESS_TYPE_CONVERSION (rhs1);
+      if (TREE_CODE (rhs0) == SSA_NAME
+         && (TREE_CODE (rhs1) != SSA_NAME || code == MINUS_EXPR))
+       {
+         /* Match an assignment under the form:
+            "a = b +- ...".
+            Use tail-recursion for the simple case.  */
+         *evolution_of_loop = add_to_evolution
+             (loop->num, chrec_convert (type, *evolution_of_loop,
+                                        at_stmt),
+              code, rhs1, at_stmt);
+         expr = rhs0;
+         goto tail_recurse;
+       }
+      /* Else search for the SCC in both rhs0 and rhs1.  */
       return follow_ssa_edge_binary (loop, at_stmt, type, rhs0, code, rhs1,
                                     halting_phi, evolution_of_loop, limit);
 
     case ASSERT_EXPR:
       /* This assignment is of the form: "a_1 = ASSERT_EXPR <a_2, ...>"
         It must be handled as a copy assignment of the form a_1 = a_2.  */
-      return follow_ssa_edge_expr (loop, at_stmt, ASSERT_EXPR_VAR (rhs0),
-                                  halting_phi, evolution_of_loop, limit);
+      expr = ASSERT_EXPR_VAR (rhs0);
+      goto tail_recurse;
 
     default:
       return t_false;