> Looks ok to me, but can you add a testcase please?
>
> Also check if 4.9 is affected.
Sorry for the delay, this finally made it back to the top of my to-do
list. Testcase included which fails without and passes with this
patch. 4.9 is affected and the same patch fixes it. Tested on
rx-elf, x86 32/64, and arm32.
2014-10-29 DJ Delorie <d...@redhat.com>
* expmed.c (strict_volatile_bitfield_p): Fix off-by-one error.
2014-10-29 DJ Delorie <d...@redhat.com>
* gcc.dg/20141029-1.c: New.
Index: expmed.c
===================================================================
--- expmed.c (revision 216811)
+++ expmed.c (working copy)
@@ -454,13 +454,13 @@ strict_volatile_bitfield_p (rtx op0, uns
&& bitnum % GET_MODE_ALIGNMENT (fieldmode) + bitsize > modesize))
return false;
/* Check for cases where the C++ memory model applies. */
if (bitregion_end != 0
&& (bitnum - bitnum % modesize < bitregion_start
- || bitnum - bitnum % modesize + modesize > bitregion_end))
+ || bitnum - bitnum % modesize + modesize - 1 > bitregion_end))
return false;
return true;
}
/* Return true if OP is a memory and if a bitfield of size BITSIZE at
Index: testsuite/gcc.dg/20141029-1.c
===================================================================
--- testsuite/gcc.dg/20141029-1.c (revision 0)
+++ testsuite/gcc.dg/20141029-1.c (revision 0)
@@ -0,0 +1,28 @@
+/* { dg-do compile } */
+/* { dg-options "-fstrict-volatile-bitfields -fdump-rtl-final" } */
+
+#define PERIPH (*(volatile struct system_periph *)0x81234)
+
+struct system_periph {
+ union {
+ unsigned short WORD;
+ struct {
+ unsigned short a:1;
+ unsigned short b:1;
+ unsigned short :5;
+ unsigned short c:1;
+ unsigned short :8;
+ } BIT;
+ } ALL;
+};
+
+void
+foo()
+{
+ while (1)
+ {
+ PERIPH.ALL.BIT.a = 1;
+ }
+}
+/* { dg-final { scan-rtl-dump-times "mem/v(/.)*:HI" 4 "final" } } */
+/* { dg-final { cleanup-rtl-dump "final" } } */
