diff --git a/ext/Devel-Peek/t/Peek.t b/ext/Devel-Peek/t/Peek.t
index a8c68c80e60d..30b654ff9408 100644
--- a/ext/Devel-Peek/t/Peek.t
+++ b/ext/Devel-Peek/t/Peek.t
@@ -355,9 +355,10 @@ do_test('reference to named subroutine without prototype',
 
 if ($] >= 5.011) {
 # note the conditionals on ENGINE and INTFLAGS were introduced in 5.19.9
-do_test('reference to regexp',
-        qr(tic),
-'SV = $RV\\($ADDR\\) at $ADDR
+    # We are taking great care to curate this test as if the module is dual life
+    # (or we actively want to cherry-pick entire chunks of it back to maint)
+    # Is this a good idea?
+    my $raw = 'SV = $RV\\($ADDR\\) at $ADDR
   REFCNT = 1
   FLAGS = \\(ROK\\)
   RV = $ADDR
@@ -423,7 +424,13 @@ do_test('reference to regexp',
     OFFS = $ADDR
     QR_ANONCV = 0x0(?:
     SAVED_COPY = 0x0)?'
-));
+);
+
+    $raw =~ s/ EXTFLAGS = 0x680000 / EXTFLAGS = 0x340000 /g
+        if $] >= 5.035;
+    do_test('reference to regexp',
+            qr(tic),
+            $raw);
 } else {
 do_test('reference to regexp',
         qr(tic),
diff --git a/regexp.h b/regexp.h
index e40420613353..b14351a71515 100644
--- a/regexp.h
+++ b/regexp.h
@@ -414,7 +414,7 @@ and check for NULL.
  * For the regexp bits, PL_reg_extflags_name[] in regnodes.h has a comment
  * giving which bits are used/unused */
 
-#  define RXf_BASE_SHIFT (_RXf_PMf_SHIFT_NEXT + 2)
+#  define RXf_BASE_SHIFT (_RXf_PMf_SHIFT_NEXT + 1)
 
 /* What we have seen */
 #  define RXf_NO_INPLACE_SUBST  (1U<<(RXf_BASE_SHIFT+2))
@@ -455,7 +455,7 @@ and check for NULL.
  * highest bit position should be used, so that if RXf_BASE_SHIFT gets
  * increased, the #error below will be triggered so that you will be reminded
  * to adjust things at the other end to keep the bit positions unchanged */
-#  if RXf_BASE_SHIFT+17 > 31
+#  if RXf_BASE_SHIFT+18 > 31
 #     error Too many RXf_PMf bits used.  See comments at beginning of these for what to do
 #  endif
 
diff --git a/regnodes.h b/regnodes.h
index 94b71102eb3b..205342f77312 100644
--- a/regnodes.h
+++ b/regnodes.h
@@ -1654,7 +1654,7 @@ EXTCONST char * const PL_reg_name[] = {
 EXTCONST char * PL_reg_extflags_name[];
 #else
 EXTCONST char * const PL_reg_extflags_name[] = {
-	/* Bits in extflags defined: 11111111111111110000111111111111 */
+	/* Bits in extflags defined: 01111111111111111000111111111111 */
 	"MULTILINE",        /* 0x00000001 */
 	"SINGLELINE",       /* 0x00000002 */
 	"FOLD",             /* 0x00000004 */
@@ -1670,23 +1670,23 @@ EXTCONST char * const PL_reg_extflags_name[] = {
 	"UNUSED_BIT_12",    /* 0x00001000 */
 	"UNUSED_BIT_13",    /* 0x00002000 */
 	"UNUSED_BIT_14",    /* 0x00004000 */
-	"UNUSED_BIT_15",    /* 0x00008000 */
-	"NO_INPLACE_SUBST", /* 0x00010000 */
-	"EVAL_SEEN",        /* 0x00020000 */
-	"UNBOUNDED_QUANTIFIER_SEEN",/* 0x00040000 */
-	"CHECK_ALL",        /* 0x00080000 */
-	"MATCH_UTF8",       /* 0x00100000 */
-	"USE_INTUIT_NOML",  /* 0x00200000 */
-	"USE_INTUIT_ML",    /* 0x00400000 */
-	"INTUIT_TAIL",      /* 0x00800000 */
-	"IS_ANCHORED",      /* 0x01000000 */
-	"COPY_DONE",        /* 0x02000000 */
-	"TAINTED_SEEN",     /* 0x04000000 */
-	"TAINTED",          /* 0x08000000 */
-	"START_ONLY",       /* 0x10000000 */
-	"SKIPWHITE",        /* 0x20000000 */
-	"WHITE",            /* 0x40000000 */
-	"NULL",             /* 0x80000000 */
+	"NO_INPLACE_SUBST", /* 0x00008000 */
+	"EVAL_SEEN",        /* 0x00010000 */
+	"UNBOUNDED_QUANTIFIER_SEEN",/* 0x00020000 */
+	"CHECK_ALL",        /* 0x00040000 */
+	"MATCH_UTF8",       /* 0x00080000 */
+	"USE_INTUIT_NOML",  /* 0x00100000 */
+	"USE_INTUIT_ML",    /* 0x00200000 */
+	"INTUIT_TAIL",      /* 0x00400000 */
+	"IS_ANCHORED",      /* 0x00800000 */
+	"COPY_DONE",        /* 0x01000000 */
+	"TAINTED_SEEN",     /* 0x02000000 */
+	"TAINTED",          /* 0x04000000 */
+	"START_ONLY",       /* 0x08000000 */
+	"SKIPWHITE",        /* 0x10000000 */
+	"WHITE",            /* 0x20000000 */
+	"NULL",             /* 0x40000000 */
+	"UNUSED_BIT_31",    /* 0x80000000 */
 };
 #endif /* DOINIT */