alias.c (aliases_everything_p): Remove.

2012-06-11  Richard Guenther  <rguenther@suse.de>

	* alias.c (aliases_everything_p): Remove.
	(DIFFERENT_ALIAS_SETS_P): Likewise.
	(true_dependence_1): Use mems_in_disjoint_alias_sets_p directly.
	Do not use aliases_everything_p or special-case ANDs.  Do not
	special-case BLKmode moves.
	(may_alias_p): Likewise.  Handle BLKmode similar like everywhere
	- for SCATCH only.

From-SVN: r188384

1 files changed, 6 insertions, 47 deletions

diff --git a/gcc/alias.c b/gcc/alias.c
index 322fe0c..88a3b7e 100644
--- a/gcc/alias.c
+++ b/gcc/alias.c
@@ -156,7 +156,6 @@ static rtx find_base_value (rtx);
 static int mems_in_disjoint_alias_sets_p (const_rtx, const_rtx);
 static int insert_subset_children (splay_tree_node, void*);
 static alias_set_entry get_alias_set_entry (alias_set_type);
-static int aliases_everything_p (const_rtx);
 static bool nonoverlapping_component_refs_p (const_tree, const_tree);
 static tree decl_for_component_ref (tree);
 static int write_dependence_p (const_rtx, const_rtx, int);
@@ -168,13 +167,6 @@ static void memory_modified_1 (rtx, const_rtx, void *);
 /* Returns the size in bytes of the mode of X.  */
 #define SIZE_FOR_MODE(X) (GET_MODE_SIZE (GET_MODE (X)))
 
-/* Returns nonzero if MEM1 and MEM2 do not alias because they are in
-   different alias sets.  We ignore alias sets in functions making use
-   of variable arguments because the va_arg macros on some systems are
-   not legal ANSI C.  */
-#define DIFFERENT_ALIAS_SETS_P(MEM1, MEM2)			\
-  mems_in_disjoint_alias_sets_p (MEM1, MEM2)
-
 /* Cap the number of passes we make over the insns propagating alias
    information through set chains.   10 is a completely arbitrary choice.  */
 #define MAX_ALIAS_LOOP_PASSES 10
@@ -2188,20 +2180,6 @@ read_dependence (const_rtx mem, const_rtx x)
   return MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem);
 }
 
-/* Returns nonzero if something about the mode or address format MEM1
-   indicates that it might well alias *anything*.  */
-
-static int
-aliases_everything_p (const_rtx mem)
-{
-  if (GET_CODE (XEXP (mem, 0)) == AND)
-    /* If the address is an AND, it's very hard to know at what it is
-       actually pointing.  */
-    return 1;
-
-  return 0;
-}
-
 /* Return true if we can determine that the fields referenced cannot
    overlap for any pair of objects.  */
 
@@ -2535,25 +2513,12 @@ true_dependence_1 (const_rtx mem, enum machine_mode mem_mode, rtx mem_addr,
 				 SIZE_FOR_MODE (x), x_addr, 0)) != -1)
     return ret;
 
-  if (DIFFERENT_ALIAS_SETS_P (x, mem))
+  if (mems_in_disjoint_alias_sets_p (x, mem))
     return 0;
 
   if (nonoverlapping_memrefs_p (mem, x, false))
     return 0;
 
-  if (aliases_everything_p (x))
-    return 1;
-
-  /* We cannot use aliases_everything_p to test MEM, since we must look
-     at MEM_ADDR, rather than XEXP (mem, 0).  */
-  if (GET_CODE (mem_addr) == AND)
-    return 1;
-
-  /* ??? In true_dependence we also allow BLKmode to alias anything.  Why
-     don't we do this in anti_dependence and output_dependence?  */
-  if (mem_mode == BLKmode || GET_MODE (x) == BLKmode)
-    return 1;
-
   return rtx_refs_may_alias_p (x, mem, true);
 }
 
@@ -2680,10 +2645,12 @@ may_alias_p (const_rtx mem, const_rtx x)
   if (MEM_VOLATILE_P (x) && MEM_VOLATILE_P (mem))
     return 1;
 
-  /* ??? In true_dependence we also allow BLKmode to alias anything. */
-  if (GET_MODE (mem) == BLKmode || GET_MODE (x) == BLKmode)
+  /* (mem:BLK (scratch)) is a special mechanism to conflict with everything.
+     This is used in epilogue deallocation functions.  */
+  if (GET_MODE (x) == BLKmode && GET_CODE (XEXP (x, 0)) == SCRATCH)
+    return 1;
+  if (GET_MODE (mem) == BLKmode && GET_CODE (XEXP (mem, 0)) == SCRATCH)
     return 1;
-    
   if (MEM_ALIAS_SET (x) == ALIAS_SET_MEMORY_BARRIER
       || MEM_ALIAS_SET (mem) == ALIAS_SET_MEMORY_BARRIER)
     return 1;
@@ -2722,14 +2689,6 @@ may_alias_p (const_rtx mem, const_rtx x)
   if (nonoverlapping_memrefs_p (mem, x, true))
     return 0;
 
-  if (aliases_everything_p (x))
-    return 1;
-
-  /* We cannot use aliases_everything_p to test MEM, since we must look
-     at MEM_ADDR, rather than XEXP (mem, 0).  */
-  if (GET_CODE (mem_addr) == AND)
-    return 1;
-
   /* TBAA not valid for loop_invarint */
   return rtx_refs_may_alias_p (x, mem, false);
 }