re PR middle-end/59990 (incorrect memcpy optimization)

2014-01-31  Richard Biener  <rguenther@suse.de>

	PR middle-end/59990
	* builtins.c (fold_builtin_memory_op): Make sure to not
	use a floating-point mode or a boolean or enumeral type for
	the copy operation.

	* gcc.dg/torture/pr59990.c: New testcase.

From-SVN: r207338

gcc/ChangeLog

+2014-01-31  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/59990
+	* builtins.c (fold_builtin_memory_op): Make sure to not
+	use a floating-point mode or a boolean or enumeral type for
+	the copy operation.
+
 2014-01-30  DJ Delorie  <dj@redhat.com>
 
 	* config/msp430/msp430.h (LIB_SPEC): Add -lcrt

gcc/builtins.c

@@ -8851,6 +8851,12 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
       if (!POINTER_TYPE_P (TREE_TYPE (src))
 	  || !POINTER_TYPE_P (TREE_TYPE (dest)))
 	return NULL_TREE;
+      /* In the following try to find a type that is most natural to be
+	 used for the memcpy source and destination and that allows
+	 the most optimization when memcpy is turned into a plain assignment
+	 using that type.  In theory we could always use a char[len] type
+	 but that only gains us that the destination and source possibly
+	 no longer will have their address taken.  */
       /* As we fold (void *)(p + CST) to (void *)p + CST undo this here.  */
       if (TREE_CODE (src) == POINTER_PLUS_EXPR)
 	{
@@ -8886,6 +8892,41 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
 	  || TREE_ADDRESSABLE (desttype))
 	return NULL_TREE;
 
+      /* Make sure we are not copying using a floating-point mode or
+         a type whose size possibly does not match its precision.  */
+      if (FLOAT_MODE_P (TYPE_MODE (desttype))
+	  || TREE_CODE (desttype) == BOOLEAN_TYPE
+	  || TREE_CODE (desttype) == ENUMERAL_TYPE)
+	{
+	  /* A more suitable int_mode_for_mode would return a vector
+	     integer mode for a vector float mode or a integer complex
+	     mode for a float complex mode if there isn't a regular
+	     integer mode covering the mode of desttype.  */
+	  enum machine_mode mode = int_mode_for_mode (TYPE_MODE (desttype));
+	  if (mode == BLKmode)
+	    desttype = NULL_TREE;
+	  else
+	    desttype = build_nonstandard_integer_type (GET_MODE_BITSIZE (mode),
+						       1);
+	}
+      if (FLOAT_MODE_P (TYPE_MODE (srctype))
+	  || TREE_CODE (srctype) == BOOLEAN_TYPE
+	  || TREE_CODE (srctype) == ENUMERAL_TYPE)
+	{
+	  enum machine_mode mode = int_mode_for_mode (TYPE_MODE (srctype));
+	  if (mode == BLKmode)
+	    srctype = NULL_TREE;
+	  else
+	    srctype = build_nonstandard_integer_type (GET_MODE_BITSIZE (mode),
+						      1);
+	}
+      if (!srctype)
+	srctype = desttype;
+      if (!desttype)
+	desttype = srctype;
+      if (!srctype)
+	return NULL_TREE;
+
       src_align = get_pointer_alignment (src);
       dest_align = get_pointer_alignment (dest);
       if (dest_align < TYPE_ALIGN (desttype)
@@ -8899,29 +8940,6 @@ fold_builtin_memory_op (location_t loc, tree dest, tree src,
       off0 = build_int_cst (build_pointer_type_for_mode (char_type_node,
 							 ptr_mode, true), 0);
 
-      /* For -fsanitize={bool,enum} make sure the load isn't performed in
-	 the bool or enum type.  */
-      if (((flag_sanitize & SANITIZE_BOOL)
-	   && TREE_CODE (desttype) == BOOLEAN_TYPE)
-	  || ((flag_sanitize & SANITIZE_ENUM)
-	      && TREE_CODE (desttype) == ENUMERAL_TYPE))
-	{
-	  tree destitype
-	    = lang_hooks.types.type_for_mode (TYPE_MODE (desttype),
-					      TYPE_UNSIGNED (desttype));
-	  desttype = build_aligned_type (destitype, TYPE_ALIGN (desttype));
-	}
-      if (((flag_sanitize & SANITIZE_BOOL)
-	   && TREE_CODE (srctype) == BOOLEAN_TYPE)
-	  || ((flag_sanitize & SANITIZE_ENUM)
-	      && TREE_CODE (srctype) == ENUMERAL_TYPE))
-	{
-	  tree srcitype
-	    = lang_hooks.types.type_for_mode (TYPE_MODE (srctype),
-					      TYPE_UNSIGNED (srctype));
-	  srctype = build_aligned_type (srcitype, TYPE_ALIGN (srctype));
-	}
-
       destvar = dest;
       STRIP_NOPS (destvar);
       if (TREE_CODE (destvar) == ADDR_EXPR

gcc/testsuite/ChangeLog

+2014-01-31  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/59990
+	* gcc.dg/torture/pr59990.c: New testcase.
+
 2014-01-31  Jakub Jelinek  <jakub@redhat.com>
 
 	* lib/tsan-dg.exp (tsan_init): Try to run a trivial program,

gcc/testsuite/gcc.dg/torture/pr59990.c

+/* { dg-do run } */
+
+extern void abort (void);
+
+unsigned char value[4] = { 66, 9, 160, 255 };
+
+int main (void)
+{
+  volatile float f;
+  unsigned char a[4];
+
+  __builtin_memcpy ((void *)&f, value, 4);
+  __builtin_memcpy (a, (void *)&f, 4);
+  if (a[2] != 160)
+    abort ();
+
+  return 0;
+}