[ree] PR rtl-optimization/78038: Handle global register dataflow definitions in ree

	PR rtl-optimization/78038
	* ree.c (get_defs): Return NULL if a defining insn for REG cannot
	be deduced to set REG through the RTL structure.
	(make_defs_and_copies_lists): Return false on a failing get_defs call.

	* gcc.target/aarch64/pr78038.c: New test.

From-SVN: r241395

gcc/ChangeLog

+2016-10-21  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR rtl-optimization/78038
+	* ree.c (get_defs): Return NULL if a defining insn for REG cannot
+	be deduced to set REG through the RTL structure.
+	(make_defs_and_copies_lists): Return false on a failing get_defs call.
+
 2016-10-21  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/78051

gcc/ree.c

@@ -482,6 +482,14 @@ get_defs (rtx_insn *insn, rtx reg, vec<rtx_insn *> *dest)
         return NULL;
       if (DF_REF_INSN_INFO (ref_link->ref) == NULL)
         return NULL;
+      /* As global regs are assumed to be defined at each function call
+	 dataflow can report a call_insn as being a definition of REG.
+	 But we can't do anything with that in this pass so proceed only
+	 if the instruction really sets REG in a way that can be deduced
+	 from the RTL structure.  */
+      if (global_regs[REGNO (reg)]
+	  && !set_of (reg, DF_REF_INSN (ref_link->ref)))
+	return NULL;
     }
 
   if (dest)
@@ -580,7 +588,7 @@ make_defs_and_copies_lists (rtx_insn *extend_insn, const_rtx set_pat,
 
   /* Initialize the work list.  */
   if (!get_defs (extend_insn, src_reg, &state->work_list))
-    gcc_unreachable ();
+    return false;
 
   is_insn_visited = XCNEWVEC (bool, max_insn_uid);
 

gcc/testsuite/ChangeLog

+2016-10-21  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR rtl-optimization/78038
+	* gcc.target/aarch64/pr78038.c: New test.
+
 2016-10-21  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/78051

gcc/testsuite/gcc.target/aarch64/pr78038.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+/* PR rtl-optimization/78038.
+   Make sure ree can gracefully handle extensions of the global
+   variable register after a call.  */
+
+typedef void (*test_fptr_t) (void);
+void
+test_f (void)
+{
+}
+test_fptr_t test_fptr = test_f;
+
+struct test2_s
+{
+  int f;
+};
+
+register struct test2_s *g __asm__("x28");
+
+void
+do_something ()
+{
+  test_fptr ();
+  struct test2_s *p1 = 0;
+  *p1 = *g;
+}