tree.h (get_object_alignment): Adjust prototype.

2010-08-10  Richard Guenther  <rguenther@suse.de>

	* tree.h (get_object_alignment): Adjust prototype.
	* builtins.c (get_object_alignment): Return unsigned int,
	drop the align parameter.  Handle MEM_REF, MISALIGNED_INDIRECT_REF
	and TARGET_MEM_REF properly.
	(get_pointer_alignment): Adjust.
	* emit-rtl.c (get_mem_align_offset): Adjust comment.
	(set_mem_attributes_minus_bitpos): Adjust.
	* tree-ssa-ccp.c (get_value_from_alignment): Adjust.

From-SVN: r163051

gcc/ChangeLog

 2010-08-10  Richard Guenther  <rguenther@suse.de>
 
+	* tree.h (get_object_alignment): Adjust prototype.
+	* builtins.c (get_object_alignment): Return unsigned int,
+	drop the align parameter.  Handle MEM_REF, MISALIGNED_INDIRECT_REF
+	and TARGET_MEM_REF properly.
+	(get_pointer_alignment): Adjust.
+	* emit-rtl.c (get_mem_align_offset): Adjust comment.
+	(set_mem_attributes_minus_bitpos): Adjust.
+	* tree-ssa-ccp.c (get_value_from_alignment): Adjust.
+
+2010-08-10  Richard Guenther  <rguenther@suse.de>
+
 	* tree-ssa-copy.c (set_copy_of_val): Use operand_equal_p.
 	(copy_prop_visit_assignment): Simplify.
 	(copy_prop_visit_stmt): Also visit assignments from

gcc/builtins.c

@@ -267,26 +267,83 @@ called_as_built_in (tree node)
 }
 
 /* Return the alignment in bits of EXP, an object.
-   Don't return more than MAX_ALIGN no matter what, ALIGN is the inital
-   guessed alignment e.g. from type alignment.  */
+   Don't return more than MAX_ALIGN no matter what.  */
 
-int
-get_object_alignment (tree exp, unsigned int align, unsigned int max_align)
+unsigned int
+get_object_alignment (tree exp, unsigned int max_align)
 {
-  unsigned int inner;
-
-  inner = max_align;
-  if (handled_component_p (exp))
-   {
   HOST_WIDE_INT bitsize, bitpos;
   tree offset;
   enum machine_mode mode;
   int unsignedp, volatilep;
+  unsigned int align, inner;
 
+  /* Get the innermost object and the constant (bitpos) and possibly
+     variable (offset) offset of the access.  */
   exp = get_inner_reference (exp, &bitsize, &bitpos, &offset,
 			     &mode, &unsignedp, &volatilep, true);
-      if (bitpos)
-	inner = MIN (inner, (unsigned) (bitpos & -bitpos));
+
+  /* Extract alignment information from the innermost object and
+     possibly adjust bitpos and offset.  */
+  if (TREE_CODE (exp) == CONST_DECL)
+    exp = DECL_INITIAL (exp);
+  if (DECL_P (exp)
+      && TREE_CODE (exp) != LABEL_DECL)
+    align = DECL_ALIGN (exp);
+  else if (CONSTANT_CLASS_P (exp))
+    {
+      align = TYPE_ALIGN (TREE_TYPE (exp));
+#ifdef CONSTANT_ALIGNMENT
+      align = (unsigned)CONSTANT_ALIGNMENT (exp, align);
+#endif
+    }
+  else if (TREE_CODE (exp) == VIEW_CONVERT_EXPR)
+    align = TYPE_ALIGN (TREE_TYPE (exp));
+  else if (TREE_CODE (exp) == INDIRECT_REF)
+    align = TYPE_ALIGN (TREE_TYPE (exp));
+  else if (TREE_CODE (exp) == MISALIGNED_INDIRECT_REF)
+    {
+      tree op1 = TREE_OPERAND (exp, 1);
+      align = integer_zerop (op1) ? BITS_PER_UNIT : TREE_INT_CST_LOW (op1);
+    }
+  else if (TREE_CODE (exp) == MEM_REF)
+    {
+      tree addr = TREE_OPERAND (exp, 0);
+      if (TREE_CODE (addr) == BIT_AND_EXPR
+	  && TREE_CODE (TREE_OPERAND (addr, 1)) == INTEGER_CST)
+	{
+	  align = (TREE_INT_CST_LOW (TREE_OPERAND (addr, 1))
+		    & -TREE_INT_CST_LOW (TREE_OPERAND (addr, 1)));
+	  align *= BITS_PER_UNIT;
+	  addr = TREE_OPERAND (addr, 0);
+	}
+      else
+	align = BITS_PER_UNIT;
+      if (TREE_CODE (addr) == ADDR_EXPR)
+	align = MAX (align, get_object_alignment (TREE_OPERAND (addr, 0),
+						  max_align));
+      bitpos += mem_ref_offset (exp).low * BITS_PER_UNIT;
+    }
+  else if (TREE_CODE (exp) == TARGET_MEM_REF
+	   && TMR_SYMBOL (exp))
+    {
+      align = get_object_alignment (TMR_SYMBOL (exp), max_align);
+      if (TMR_OFFSET (exp))
+        bitpos += TREE_INT_CST_LOW (TMR_OFFSET (exp)) * BITS_PER_UNIT;
+      if (TMR_INDEX (exp) && TMR_STEP (exp))
+	{
+	  unsigned HOST_WIDE_INT step = TREE_INT_CST_LOW (TMR_STEP (exp));
+	  align = MIN (align, (step & -step) * BITS_PER_UNIT);
+	}
+      else if (TMR_INDEX (exp))
+	align = BITS_PER_UNIT;
+    }
+  else
+    align = BITS_PER_UNIT;
+
+  /* If there is a non-constant offset part extract the maximum
+     alignment that can prevail.  */
+  inner = max_align;
   while (offset)
     {
       tree next_offset;
@@ -327,21 +384,18 @@ get_object_alignment (tree exp, unsigned int align, unsigned int max_align)
 	}
       offset = next_offset;
     }
-    }
-  if (TREE_CODE (exp) == CONST_DECL)
-    exp = DECL_INITIAL (exp);
-  if (DECL_P (exp)
-      && TREE_CODE (exp) != LABEL_DECL)
-    align = MIN (inner, DECL_ALIGN (exp));
-#ifdef CONSTANT_ALIGNMENT
-  else if (CONSTANT_CLASS_P (exp))
-    align = MIN (inner, (unsigned)CONSTANT_ALIGNMENT (exp, align));
-#endif
-  else if (TREE_CODE (exp) == VIEW_CONVERT_EXPR
-	   || TREE_CODE (exp) == INDIRECT_REF)
-    align = MIN (TYPE_ALIGN (TREE_TYPE (exp)), inner);
-  else
+
+  /* Alignment is innermost object alignment adjusted by the constant
+     and non-constant offset parts.  */
   align = MIN (align, inner);
+  bitpos = bitpos & (align - 1);
+
+  /* align and bitpos now specify known low bits of the pointer.
+     ptr & (align - 1) == bitpos.  */
+
+  if (bitpos != 0)
+    align = (bitpos & -bitpos);
+
   return MIN (align, max_align);
 }
 
@@ -407,7 +461,7 @@ get_pointer_alignment (tree exp, unsigned int max_align)
 
 	case ADDR_EXPR:
 	  /* See what we are pointing at and look at its alignment.  */
-	  return get_object_alignment (TREE_OPERAND (exp, 0), align, max_align);
+	  return get_object_alignment (TREE_OPERAND (exp, 0), max_align);
 
 	default:
 	  return align;

gcc/emit-rtl.c

@@ -1459,7 +1459,8 @@ get_mem_align_offset (rtx mem, unsigned int align)
   /* This function can't use
      if (!MEM_EXPR (mem) || !MEM_OFFSET (mem)
 	 || !CONST_INT_P (MEM_OFFSET (mem))
-	 || (get_object_alignment (MEM_EXPR (mem), MEM_ALIGN (mem), align)
+	 || (MAX (MEM_ALIGN (mem),
+	          get_object_alignment (MEM_EXPR (mem), align))
 	     < align))
        return -1;
      else
@@ -1796,8 +1797,7 @@ set_mem_attributes_minus_bitpos (rtx ref, tree t, int objectp,
 
       if (!align_computed && !INDIRECT_REF_P (t))
 	{
-	  unsigned int obj_align
-	    = get_object_alignment (t, align, BIGGEST_ALIGNMENT);
+	  unsigned int obj_align = get_object_alignment (t, BIGGEST_ALIGNMENT);
 	  align = MAX (align, obj_align);
 	}
     }

gcc/tree-ssa-ccp.c

@@ -515,8 +515,7 @@ get_value_from_alignment (tree expr)
     val = bit_value_binop (PLUS_EXPR, TREE_TYPE (expr),
 			   TREE_OPERAND (base, 0), TREE_OPERAND (base, 1));
   else if (base
-	   && ((align = get_object_alignment (base, BITS_PER_UNIT,
-					      BIGGEST_ALIGNMENT))
+	   && ((align = get_object_alignment (base, BIGGEST_ALIGNMENT))
 		> BITS_PER_UNIT))
     {
       val.lattice_val = CONSTANT;

gcc/tree.h

@@ -5036,7 +5036,7 @@ extern bool can_trust_pointer_alignment (void);
 extern int get_pointer_alignment (tree, unsigned int);
 extern bool is_builtin_name (const char *);
 extern bool is_builtin_fn (tree);
-extern int get_object_alignment (tree, unsigned int, unsigned int);
+extern unsigned int get_object_alignment (tree, unsigned int);
 extern tree fold_call_stmt (gimple, bool);
 extern tree gimple_fold_builtin_snprintf_chk (gimple, tree, enum built_in_function);
 extern tree make_range (tree, int *, tree *, tree *, bool *);