builtins.c (expand_builtin_memory_copy_args): Add might_overlap parm.

2019-10-02  Aaron Sawdey <acsawdey@linux.ibm.com>

	* builtins.c (expand_builtin_memory_copy_args): Add might_overlap parm.
	(expand_builtin_memcpy): Use might_overlap parm.
	(expand_builtin_mempcpy_args): Use might_overlap parm.
	(expand_builtin_memmove): Call expand_builtin_memory_copy_args.
	(expand_builtin_memory_copy_args): Add might_overlap parm.
	* expr.c (emit_block_move_via_cpymem): Rename to
	emit_block_move_via_pattern, add might_overlap parm, use cpymem
	or movmem optab as appropriate.
	(emit_block_move_hints): Add might_overlap parm, do the right
	thing for might_overlap==true.
	* expr.h (emit_block_move_hints): Update prototype.

From-SVN: r276461

1 files changed, 17 insertions, 10 deletions

diff --git a/gcc/builtins.c b/gcc/builtins.c
index 1fd4b88..fa17afd 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -127,7 +127,8 @@ static rtx expand_builtin_memchr (tree, rtx);
 static rtx expand_builtin_memcpy (tree, rtx);
 static rtx expand_builtin_memory_copy_args (tree dest, tree src, tree len,
 					    rtx target, tree exp,
-					    memop_ret retmode);
+					    memop_ret retmode,
+					    bool might_overlap);
 static rtx expand_builtin_memmove (tree, rtx);
 static rtx expand_builtin_mempcpy (tree, rtx);
 static rtx expand_builtin_mempcpy_args (tree, tree, tree, rtx, tree, memop_ret);
@@ -3790,14 +3791,14 @@ expand_builtin_memcpy (tree exp, rtx target)
   check_memop_access (exp, dest, src, len);
 
   return expand_builtin_memory_copy_args (dest, src, len, target, exp,
-					  /*retmode=*/ RETURN_BEGIN);
+					  /*retmode=*/ RETURN_BEGIN, false);
 }
 
 /* Check a call EXP to the memmove built-in for validity.
    Return NULL_RTX on both success and failure.  */
 
 static rtx
-expand_builtin_memmove (tree exp, rtx)
+expand_builtin_memmove (tree exp, rtx target)
 {
   if (!validate_arglist (exp,
  			 POINTER_TYPE, POINTER_TYPE, INTEGER_TYPE, VOID_TYPE))
@@ -3809,7 +3810,8 @@ expand_builtin_memmove (tree exp, rtx)
 
   check_memop_access (exp, dest, src, len);
 
-  return NULL_RTX;
+  return expand_builtin_memory_copy_args (dest, src, len, target, exp,
+					  /*retmode=*/ RETURN_BEGIN, true);
 }
 
 /* Expand a call EXP to the mempcpy builtin.
@@ -3858,7 +3860,8 @@ expand_builtin_mempcpy (tree exp, rtx target)
 
 static rtx
 expand_builtin_memory_copy_args (tree dest, tree src, tree len,
-				 rtx target, tree exp, memop_ret retmode)
+				 rtx target, tree exp, memop_ret retmode,
+				 bool might_overlap)
 {
   const char *src_str;
   unsigned int src_align = get_pointer_alignment (src);
@@ -3894,9 +3897,12 @@ expand_builtin_memory_copy_args (tree dest, tree src, tree len,
 			&probable_max_size);
   src_str = c_getstr (src);
 
-  /* If SRC is a string constant and block move would be done
-     by pieces, we can avoid loading the string from memory
-     and only stored the computed constants.  */
+  /* If SRC is a string constant and block move would be done by
+     pieces, we can avoid loading the string from memory and only
+     stored the computed constants.  This works in the overlap
+     (memmove) case as well because store_by_pieces just generates a
+     series of stores of constants from the string constant returned
+     by c_getstr().  */
   if (src_str
       && CONST_INT_P (len_rtx)
       && (unsigned HOST_WIDE_INT) INTVAL (len_rtx) <= strlen (src_str) + 1
@@ -3923,13 +3929,14 @@ expand_builtin_memory_copy_args (tree dest, tree src, tree len,
     method = BLOCK_OP_TAILCALL;
   bool use_mempcpy_call = (targetm.libc_has_fast_function (BUILT_IN_MEMPCPY)
 			   && retmode == RETURN_END
+			   && !might_overlap
 			   && target != const0_rtx);
   if (use_mempcpy_call)
     method = BLOCK_OP_NO_LIBCALL_RET;
   dest_addr = emit_block_move_hints (dest_mem, src_mem, len_rtx, method,
 				     expected_align, expected_size,
 				     min_size, max_size, probable_max_size,
-				     use_mempcpy_call, &is_move_done);
+				     use_mempcpy_call, &is_move_done, might_overlap);
 
   /* Bail out when a mempcpy call would be expanded as libcall and when
      we have a target that provides a fast implementation
@@ -3962,7 +3969,7 @@ expand_builtin_mempcpy_args (tree dest, tree src, tree len,
 			     rtx target, tree orig_exp, memop_ret retmode)
 {
   return expand_builtin_memory_copy_args (dest, src, len, target, orig_exp,
-					  retmode);
+					  retmode, false);
 }
 
 /* Expand into a movstr instruction, if one is available.  Return NULL_RTX if