--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/pr23623.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,47 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target size32plus } */
+/* { dg-options "-fstrict-volatile-bitfields -fdump-rtl-final" } */
+
+/* With -fstrict-volatile-bitfields, the volatile accesses to bf2.b
+   and bf3.b must do unsigned int reads/writes.  The non-volatile
+   accesses to bf1.b are not so constrained.  */
+
+extern struct
+{
+  unsigned int b : 1;
+  unsigned int : 31;
+} __attribute__((aligned(4))) bf1;
+
+extern volatile struct
+{
+  unsigned int b : 1;
+  unsigned int : 31;
+} __attribute__((aligned(4))) bf2;
+
+extern struct
+{
+  volatile unsigned int b : 1;
+  volatile unsigned int : 31;
+} __attribute__((aligned(4))) bf3;
+
+void writeb(void)
+{
+  bf1.b = 1;
+  bf2.b = 1;	/* volatile read + volatile write */
+  bf3.b = 1;	/* volatile read + volatile write */
+}
+
+extern unsigned int x1, x2, x3;
+
+void readb(void)
+{
+  x1 = bf1.b;
+  x2 = bf2.b;   /* volatile write */
+  x3 = bf3.b;   /* volatile write */
+}
+
+/* There should be 6 volatile MEMs total, but scan-rtl-dump-times counts
+   the number of match variables and not the number of matches.  Since
+   the parenthesized subexpression in the regexp introduces an extra match
+   variable, we need to give a count of 12 instead of 6 here.  */
+/* { dg-final { scan-rtl-dump-times "mem/v(/.)*:SI" 12 "final" } } */