re PR debug/54796 (Non-addressable stack parameter debug quality regression)

	PR debug/54796
	* rtl.h: Document jump flag on VALUE.
	* cselib.h (cselib_set_value_sp_based,
	cselib_sp_based_value_p): New prototypes.
	* alias.c (find_base_term): For cselib_sp_based_value_p
	return static_reg_base_value[STACK_POINTER_REGNUM].
	* cselib.c (SP_BASED_VALUE_P): Define.
	(cselib_set_value_sp_based, cselib_sp_based_value_p): New functions.
	* var-tracking.c (add_stores): Call cselib_set_value_sp_based
	for not yet preserved VALUEs of sp on sp assignments if
	hard_frame_pointer_adjustment != -1.
	(vt_initialize): When setting hard_frame_pointer_adjustment,
	disassociate sp from its previous value and call
	cselib_set_value_sp_based on a new VALUE created for sp.

	* gcc.dg/guality/pr54796.c: New test.

From-SVN: r192494

gcc/ChangeLog

 2012-10-16  Jakub Jelinek  <jakub@redhat.com>
 
+	PR debug/54796
+	* rtl.h: Document jump flag on VALUE.
+	* cselib.h (cselib_set_value_sp_based,
+	cselib_sp_based_value_p): New prototypes.
+	* alias.c (find_base_term): For cselib_sp_based_value_p
+	return static_reg_base_value[STACK_POINTER_REGNUM].
+	* cselib.c (SP_BASED_VALUE_P): Define.
+	(cselib_set_value_sp_based, cselib_sp_based_value_p): New functions.
+	* var-tracking.c (add_stores): Call cselib_set_value_sp_based
+	for not yet preserved VALUEs of sp on sp assignments if
+	hard_frame_pointer_adjustment != -1.
+	(vt_initialize): When setting hard_frame_pointer_adjustment,
+	disassociate sp from its previous value and call
+	cselib_set_value_sp_based on a new VALUE created for sp.
+
 	PR tree-optimization/54889
 	* tree-vect-stmts.c (vectorizable_load): Add VIEW_CONVERT_EXPR if
 	ARRAY_REF newref doesn't have compatible type with vectype element

gcc/alias.c

@@ -1640,6 +1640,9 @@ find_base_term (rtx x)
       if (!val)
 	return ret;
 
+      if (cselib_sp_based_value_p (val))
+	return static_reg_base_value[STACK_POINTER_REGNUM];
+
       f = val->locs;
       /* Temporarily reset val->locs to avoid infinite recursion.  */
       val->locs = NULL;

gcc/cselib.c

@@ -210,6 +210,9 @@ void (*cselib_record_sets_hook) (rtx insn, struct cselib_set *sets,
 #define PRESERVED_VALUE_P(RTX) \
   (RTL_FLAG_CHECK1("PRESERVED_VALUE_P", (RTX), VALUE)->unchanging)
 
+#define SP_BASED_VALUE_P(RTX) \
+  (RTL_FLAG_CHECK1("SP_BASED_VALUE_P", (RTX), VALUE)->jump)
+
 
 
 /* Allocate a struct elt_list and fill in its two elements with the
@@ -739,6 +742,24 @@ cselib_preserve_only_values (void)
   gcc_assert (first_containing_mem == &dummy_val);
 }
 
+/* Arrange for a value to be marked as based on stack pointer
+   for find_base_term purposes.  */
+
+void
+cselib_set_value_sp_based (cselib_val *v)
+{
+  SP_BASED_VALUE_P (v->val_rtx) = 1;
+}
+
+/* Test whether a value is based on stack pointer for
+   find_base_term purposes.  */
+
+bool
+cselib_sp_based_value_p (cselib_val *v)
+{
+  return SP_BASED_VALUE_P (v->val_rtx);
+}
+
 /* Return the mode in which a register was last set.  If X is not a
    register, return its mode.  If the mode in which the register was
    set is not known, or the value was already clobbered, return

gcc/cselib.h

@@ -99,6 +99,8 @@ extern void cselib_preserve_only_values (void);
 extern void cselib_preserve_cfa_base_value (cselib_val *, unsigned int);
 extern void cselib_add_permanent_equiv (cselib_val *, rtx, rtx);
 extern bool cselib_have_permanent_equivalences (void);
+extern void cselib_set_value_sp_based (cselib_val *);
+extern bool cselib_sp_based_value_p (cselib_val *);
 
 extern void dump_cselib_table (FILE *);
 

gcc/rtl.h

@@ -267,7 +267,8 @@ struct GTY((chain_next ("RTX_NEXT (&%h)"),
      1 in a CALL_INSN if it is a sibling call.
      1 in a SET that is for a return.
      In a CODE_LABEL, part of the two-bit alternate entry field.
-     1 in a CONCAT is VAL_EXPR_IS_COPIED in var-tracking.c.  */
+     1 in a CONCAT is VAL_EXPR_IS_COPIED in var-tracking.c.
+     1 in a VALUE is SP_BASED_VALUE_P in cselib.c.  */
   unsigned int jump : 1;
   /* In a CODE_LABEL, part of the two-bit alternate entry field.
      1 in a MEM if it cannot trap.

gcc/testsuite/ChangeLog

 2012-10-16  Jakub Jelinek  <jakub@redhat.com>
 
+	PR debug/54796
+	* gcc.dg/guality/pr54796.c: New test.
+
 	PR tree-optimization/54889
 	* gfortran.dg/pr54889.f90: New test.
 

gcc/testsuite/gcc.dg/guality/pr54796.c

+/* PR debug/54796 */
+/* { dg-do run } */
+/* { dg-options "-g" } */
+
+__attribute__((noinline, noclone)) void
+bar (char *a, int b)
+{
+  __asm volatile ("" : "+r" (a), "+r" (b) : : "memory");
+}
+
+__attribute__((noinline, noclone)) void
+foo (int a, int b)
+{
+  int c = a;
+  char d[b];	/* { dg-final { gdb-test 17 "a" "5" } } */
+  bar (d, 2);	/* { dg-final { gdb-test 17 "b" "6" } } */
+  bar (d, 4);	/* { dg-final { gdb-test 17 "c" "5" } } */
+}
+
+int
+main ()
+{
+  foo (5, 6);
+  return 0;
+}

gcc/var-tracking.c

@@ -5769,6 +5769,11 @@ add_stores (rtx loc, const_rtx expr, void *cuip)
 
   resolve = preserve = !cselib_preserved_value_p (v);
 
+  if (loc == stack_pointer_rtx
+      && hard_frame_pointer_adjustment != -1
+      && preserve)
+    cselib_set_value_sp_based (v);
+
   nloc = replace_expr_with_values (oloc);
   if (nloc)
     oloc = nloc;
@@ -9867,6 +9872,19 @@ vt_initialize (void)
 		    {
 		      vt_init_cfa_base ();
 		      hard_frame_pointer_adjustment = fp_cfa_offset;
+		      /* Disassociate sp from fp now.  */
+		      if (MAY_HAVE_DEBUG_INSNS)
+			{
+			  cselib_val *v;
+			  cselib_invalidate_rtx (stack_pointer_rtx);
+			  v = cselib_lookup (stack_pointer_rtx, Pmode, 1,
+					     VOIDmode);
+			  if (v && !cselib_preserved_value_p (v))
+			    {
+			      cselib_set_value_sp_based (v);
+			      preserve_value (v);
+			    }
+			}
 		    }
 		}
 	    }