gcc/

	* expr.c (store_field): Avoid a direct store if the mode is larger
	than the size of the bit field.
	* stor-layout.c (layout_decl): If flag_strict_volatile_bitfields,
	treat non-volatile bit fields like volatile ones.
	* toplev.c (process_options): Disallow combination of
	-fstrict-volatile-bitfields and ABI versions less than 2.
	* config/arm/arm.c (arm_option_override): Don't enable
	flag_strict_volatile_bitfields if the ABI version is less than 2.
	* config/h8300/h8300.c (h8300_option_override): Likewise.
	* config/rx/rx.c (rx_option_override): Likewise.
	* config/m32c/m32c.c (m32c_option_override): Likewise.
	* config/sh/sh.c (sh_option_override): Likewise.

	gcc/testsuite/
	* gcc.target/arm/volatile-bitfields-4.c: New test.
	* c-c++-common/abi-bf.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@182545 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 4 insertions, 3 deletions

diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index 359541e02df..35320c2fad9 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -622,12 +622,13 @@ layout_decl (tree decl, unsigned int known_align)
 	  /* See if we can use an ordinary integer mode for a bit-field.
 	     Conditions are: a fixed size that is correct for another mode,
 	     occupying a complete byte or bytes on proper boundary,
-	     and not volatile or not -fstrict-volatile-bitfields.  */
+	     and not -fstrict-volatile-bitfields.  If the latter is set,
+	     we unfortunately can't check TREE_THIS_VOLATILE, as a cast
+	     may make a volatile object later.  */
 	  if (TYPE_SIZE (type) != 0
 	      && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST
 	      && GET_MODE_CLASS (TYPE_MODE (type)) == MODE_INT
-	      && !(TREE_THIS_VOLATILE (decl)
-		   && flag_strict_volatile_bitfields > 0))
+	      && flag_strict_volatile_bitfields <= 0)
 	    {
 	      enum machine_mode xmode
 		= mode_for_size_tree (DECL_SIZE (decl), MODE_INT, 1);