Don't check ifunc_resolver on error

Since ifunc_resolver isn't set when an error is detected, we should
lookup ifunc attribute in this case.

	PR target/85900
	PR target/85345
	* varasm.c (assemble_alias): Lookup ifunc attribute on error.

From-SVN: r260792

gcc/ChangeLog

+2018-05-24  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR target/85900
+	PR target/85345
+	* varasm.c (assemble_alias): Lookup ifunc attribute on error.
+
 2018-05-25  Jim Wilson  <jimw@sifive.com>
 
 	* config/riscv/riscv-protos.h (riscv_epilogue_uses): New.

gcc/varasm.c

@@ -5917,8 +5917,9 @@ assemble_alias (tree decl, tree target)
 # else
       if (!DECL_WEAK (decl))
 	{
+	  /* NB: ifunc_resolver isn't set when an error is detected.  */
 	  if (TREE_CODE (decl) == FUNCTION_DECL
-	      && cgraph_node::get (decl)->ifunc_resolver)
+	      && lookup_attribute ("ifunc", DECL_ATTRIBUTES (decl)))
 	    error_at (DECL_SOURCE_LOCATION (decl),
 		      "ifunc is not supported in this configuration");
 	  else