* md.texi (setmem): Document new parameter.

	* optabs.c (maybe_gen_insn): Support 9 operands.
	* builtins.c (determine_block_size): Add probable_max_size;
	support anti-ranges.
	(expand_builtin_memcpy. expand_builtin_memset_args): Pass around
	probable_max_size.
	* expr.c (emit_block_move_via_movmem, emit_block_move_hints,
	emit_block_move, clear_storage_hints, set_storage_via_setmem):
	Likewise.
	* expr.h (emit_block_move_hints, clear_storage_hints,
	set_storage_via_setmem): Update prototype.
	* i386.md (setmem, movmem patterns): Add 9th operand.
	* i386-protos.h (ix86_expand_set_or_movmem): Update prototype.
	* i386.c (ix86_expand_set_or_movmem): Take probable_max_size_exp
	argument; pass it to decide_alg.

	* gcc.target/i386/memcpy-3.c: New testcase.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@204997 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 55 insertions, 26 deletions

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 39d40cb75e7..7dc980f9bf5 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -3096,12 +3096,15 @@ builtin_memcpy_read_str (void *data, HOST_WIDE_INT offset,
 }
 
 /* LEN specify length of the block of memcpy/memset operation.
-   Figure out its range and put it into MIN_SIZE/MAX_SIZE.  */
+   Figure out its range and put it into MIN_SIZE/MAX_SIZE. 
+   In some cases we can make very likely guess on max size, then we
+   set it into PROBABLE_MAX_SIZE.  */
 
 static void
 determine_block_size (tree len, rtx len_rtx,
 		      unsigned HOST_WIDE_INT *min_size,
-		      unsigned HOST_WIDE_INT *max_size)
+		      unsigned HOST_WIDE_INT *max_size,
+		      unsigned HOST_WIDE_INT *probable_max_size)
 {
   if (CONST_INT_P (len_rtx))
     {
@@ -3111,28 +3114,47 @@ determine_block_size (tree len, rtx len_rtx,
   else
     {
       double_int min, max;
-      if (TREE_CODE (len) == SSA_NAME 
-	  && get_range_info (len, &min, &max) == VR_RANGE)
+      enum value_range_type range_type = VR_UNDEFINED;
+
+      /* Determine bounds from the type.  */
+      if (tree_fits_uhwi_p (TYPE_MIN_VALUE (TREE_TYPE (len))))
+	*min_size = tree_to_uhwi (TYPE_MIN_VALUE (TREE_TYPE (len)));
+      else
+	*min_size = 0;
+      if (tree_fits_uhwi_p (TYPE_MAX_VALUE (TREE_TYPE (len))))
+	*probable_max_size = *max_size = tree_to_uhwi (TYPE_MAX_VALUE (TREE_TYPE (len)));
+      else
+	*probable_max_size = *max_size = GET_MODE_MASK (GET_MODE (len_rtx));
+
+      if (TREE_CODE (len) == SSA_NAME)
+	range_type = get_range_info (len, &min, &max);
+      if (range_type == VR_RANGE)
 	{
-	  if (min.fits_uhwi ())
+	  if (min.fits_uhwi () && *min_size < min.to_uhwi ())
 	    *min_size = min.to_uhwi ();
-	  else
-	    *min_size = 0;
-	  if (max.fits_uhwi ())
-	    *max_size = max.to_uhwi ();
-	  else
-	    *max_size = (HOST_WIDE_INT)-1;
+	  if (max.fits_uhwi () && *max_size > max.to_uhwi ())
+	    *probable_max_size = *max_size = max.to_uhwi ();
 	}
-      else
+      else if (range_type == VR_ANTI_RANGE)
 	{
-	  if (tree_fits_uhwi_p (TYPE_MIN_VALUE (TREE_TYPE (len))))
-	    *min_size = tree_to_uhwi (TYPE_MIN_VALUE (TREE_TYPE (len)));
-	  else
-	    *min_size = 0;
-	  if (tree_fits_uhwi_p (TYPE_MAX_VALUE (TREE_TYPE (len))))
-	    *max_size = tree_to_uhwi (TYPE_MAX_VALUE (TREE_TYPE (len)));
-	  else
-	    *max_size = GET_MODE_MASK (GET_MODE (len_rtx));
+	  /* Anti range 0...N lets us to determine minmal size to N+1.  */
+	  if (min.is_zero ())
+	    {
+	      if ((max + double_int_one).fits_uhwi ())
+		*min_size = (max + double_int_one).to_uhwi ();
+	    }
+	  /* Code like
+
+	     int n;
+	     if (n < 100)
+	       memcpy (a,b, n)
+
+	     Produce anti range allowing negative values of N.  We still
+	     can use the information and make a guess that N is not negative.
+	     */
+	   else if (!max.ule (double_int_one.lshift (30))
+	            && min.fits_uhwi ())
+	     *probable_max_size = min.to_uhwi () - 1;
 	}
     }
   gcc_checking_assert (*max_size <=
@@ -3164,6 +3186,7 @@ expand_builtin_memcpy (tree exp, rtx target)
       unsigned int expected_align = 0;
       unsigned HOST_WIDE_INT min_size;
       unsigned HOST_WIDE_INT max_size;
+      unsigned HOST_WIDE_INT probable_max_size;
 
       /* If DEST is not a pointer type, call the normal function.  */
       if (dest_align == 0)
@@ -3183,7 +3206,8 @@ expand_builtin_memcpy (tree exp, rtx target)
       dest_mem = get_memory_rtx (dest, len);
       set_mem_align (dest_mem, dest_align);
       len_rtx = expand_normal (len);
-      determine_block_size (len, len_rtx, &min_size, &max_size);
+      determine_block_size (len, len_rtx, &min_size, &max_size,
+			    &probable_max_size);
       src_str = c_getstr (src);
 
       /* If SRC is a string constant and block move would be done
@@ -3213,7 +3237,7 @@ expand_builtin_memcpy (tree exp, rtx target)
 				         CALL_EXPR_TAILCALL (exp)
 				         ? BLOCK_OP_TAILCALL : BLOCK_OP_NORMAL,
 					 expected_align, expected_size,
-					 min_size, max_size);
+					 min_size, max_size, probable_max_size);
 
       if (dest_addr == 0)
 	{
@@ -3629,6 +3653,7 @@ expand_builtin_memset_args (tree dest, tree val, tree len,
   unsigned int expected_align = 0;
   unsigned HOST_WIDE_INT min_size;
   unsigned HOST_WIDE_INT max_size;
+  unsigned HOST_WIDE_INT probable_max_size;
 
   dest_align = get_pointer_alignment (dest);
 
@@ -3657,7 +3682,8 @@ expand_builtin_memset_args (tree dest, tree val, tree len,
   len = builtin_save_expr (len);
 
   len_rtx = expand_normal (len);
-  determine_block_size (len, len_rtx, &min_size, &max_size);
+  determine_block_size (len, len_rtx, &min_size, &max_size,
+			&probable_max_size);
   dest_mem = get_memory_rtx (dest, len);
   val_mode = TYPE_MODE (unsigned_char_type_node);
 
@@ -3684,7 +3710,8 @@ expand_builtin_memset_args (tree dest, tree val, tree len,
 	}
       else if (!set_storage_via_setmem (dest_mem, len_rtx, val_rtx,
 					dest_align, expected_align,
-					expected_size, min_size, max_size))
+					expected_size, min_size, max_size,
+					probable_max_size))
 	goto do_libcall;
 
       dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
@@ -3706,7 +3733,8 @@ expand_builtin_memset_args (tree dest, tree val, tree len,
       else if (!set_storage_via_setmem (dest_mem, len_rtx,
 					gen_int_mode (c, val_mode),
 					dest_align, expected_align,
-					expected_size, min_size, max_size))
+					expected_size, min_size, max_size,
+					probable_max_size))
 	goto do_libcall;
 
       dest_mem = force_operand (XEXP (dest_mem, 0), NULL_RTX);
@@ -3719,7 +3747,8 @@ expand_builtin_memset_args (tree dest, tree val, tree len,
 				   CALL_EXPR_TAILCALL (orig_exp)
 				   ? BLOCK_OP_TAILCALL : BLOCK_OP_NORMAL,
 				   expected_align, expected_size,
-				   min_size, max_size);
+				   min_size, max_size,
+				   probable_max_size);
 
   if (dest_addr == 0)
     {