[PATCH] Fix PR77697

[Richard Biener]

As noted in the PR defcodefor_name was quite broken - the following
rectifies it.

Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.

Richard.

2016-09-23  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/77697
        * tree-ssa-forwprop.c (defcodefor_name): Remove bogus code,
        signal error if we have sth ternary or unhandled.

Index: gcc/tree-ssa-forwprop.c
===================================================================
--- gcc/tree-ssa-forwprop.c     (revision 240388)
+++ gcc/tree-ssa-forwprop.c     (working copy)
@@ -1458,6 +1458,7 @@ defcodefor_name (tree name, enum tree_co
   code1 = TREE_CODE (name);
   arg11 = name;
   arg21 = NULL_TREE;
+  arg31 = NULL_TREE;
   grhs_class = get_gimple_rhs_class (code1);
 
   if (code1 == SSA_NAME)
@@ -1470,20 +1471,18 @@ defcodefor_name (tree name, enum tree_co
          code1 = gimple_assign_rhs_code (def);
          arg11 = gimple_assign_rhs1 (def);
           arg21 = gimple_assign_rhs2 (def);
-          arg31 = gimple_assign_rhs2 (def);
+          arg31 = gimple_assign_rhs3 (def);
        }
     }
-  else if (grhs_class == GIMPLE_TERNARY_RHS
-          || GIMPLE_BINARY_RHS
-          || GIMPLE_UNARY_RHS
-          || GIMPLE_SINGLE_RHS)
-    extract_ops_from_tree (name, &code1, &arg11, &arg21, &arg31);
+  else if (grhs_class != GIMPLE_SINGLE_RHS)
+    code1 = ERROR_MARK;
 
   *code = code1;
   *arg1 = arg11;
   if (arg2)
     *arg2 = arg21;
-  /* Ignore arg3 currently. */
+  if (arg31)
+    *code = ERROR_MARK;
 }