From 78d0cf80609ca6ef7050cc76fbcfe7807885b9ce Mon Sep 17 00:00:00 2001
From: Nicholas Clark <nick@ccl4.org>
Date: Mon, 11 Dec 2006 18:26:31 +0000
Subject: [PATCH] Change SvTAIL() to check that both SVpbm_TAIL|SVpbm_VALID are
 true. SVpbm_VALID is the same bit value is SVf_IVisUV, which means that PVBMs
 can't actually ever be IOK. Therefore move BmUSEFUL() into the IV union, and
 save one I32 per PVBM.

p4raw-id: //depot/perl@29518
---
 sv.h   | 15 +++++++++------
 util.c |  1 +
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/sv.h b/sv.h
index 2ddd438..379175a 100644
--- a/sv.h
+++ b/sv.h
@@ -536,7 +536,7 @@ struct xpvbm {
 	IV	xivu_iv;	/* integer value or pv offset */
 	UV	xivu_uv;
 	void *	xivu_p1;
-	I32	xivu_i32;
+	I32	xivu_i32;	/* is this constant pattern being useful? */
 	HEK *	xivu_namehek;
     }		xiv_u;
     union {
@@ -545,7 +545,6 @@ struct xpvbm {
     } xmg_u;
     HV*		xmg_stash;	/* class package */
 
-    I32		xbm_useful;	/* is this constant pattern being useful? */
     U16		xbm_previous;	/* how many characters in string before rare? */
     U8		xbm_rare;	/* rarest character in string */
 };
@@ -1063,10 +1062,13 @@ the scalar's value cannot change unless written to.
 #  define SvTAIL(sv)	({ SV *const _svi = (SV *) (sv);		\
 			    assert(SvTYPE(_svi) != SVt_PVAV);		\
 			    assert(SvTYPE(_svi) != SVt_PVHV);		\
-			    SvFLAGS(sv) & SVpbm_TAIL;			\
+			    (SvFLAGS(sv) & (SVpbm_TAIL|SVpbm_VALID))	\
+				== (SVpbm_TAIL|SVpbm_VALID);		\
 			})
 #else
-#  define SvTAIL(sv)		(SvFLAGS(sv) & SVpbm_TAIL)
+#  define SvTAIL(sv)	    ((SvFLAGS(sv) & (SVpbm_TAIL|SVpbm_VALID))	\
+			     == (SVpbm_TAIL|SVpbm_VALID));
+
 #endif
 #define SvTAIL_on(sv)		(SvFLAGS(sv) |= SVpbm_TAIL)
 #define SvTAIL_off(sv)		(SvFLAGS(sv) &= ~SVpbm_TAIL)
@@ -1317,7 +1319,8 @@ the scalar's value cannot change unless written to.
 #  define BmUSEFUL(sv)							\
 	(*({ SV *const _svi = (SV *) (sv);				\
 	    assert(SvTYPE(_svi) == SVt_PVBM);				\
-	    &(((XPVBM*) SvANY(_svi))->xbm_useful);			\
+	    assert(!SvIOK(_svi));					\
+	    &(((XPVBM*) SvANY(_svi))->xiv_u.xivu_i32);			\
 	 }))
 #  define BmPREVIOUS(sv)						\
 	(*({ SV *const _svi = (SV *) (sv);				\
@@ -1326,7 +1329,7 @@ the scalar's value cannot change unless written to.
 	 }))
 #else
 #  define BmRARE(sv)	((XPVBM*)  SvANY(sv))->xbm_rare
-#  define BmUSEFUL(sv)	((XPVBM*)  SvANY(sv))->xbm_useful
+#  define BmUSEFUL(sv)	((XPVBM*)  SvANY(sv))->xiv_u.xivu_i32
 #  define BmPREVIOUS(sv)	((XPVBM*)  SvANY(sv))->xbm_previous
 #endif
 
diff --git a/util.c b/util.c
index 358af39..fff8c8a 100644
--- a/util.c
+++ b/util.c
@@ -493,6 +493,7 @@ Perl_fbm_compile(pTHX_ SV *sv, U32 flags)
     if (len == 0)		/* TAIL might be on a zero-length string. */
 	return;
     SvUPGRADE(sv, SVt_PVBM);
+    SvIOK_off(sv);
     if (len > 2) {
 	const unsigned char *sb;
 	const U8 mlen = (len>255) ? 255 : (U8)len;
-- 
2.7.4