make the expensive ckWARN() be called as late as possible

reorganise
    if (ckWARN(FOO) && should_not_happen_condition)
to
    if (should_not_happen_condition && ckWARN(FOO))

p4raw-id: //depot/perl@25129

13 files changed, 112 insertions, 121 deletions

diff --git a/doio.c b/doio.c
index b105845e84..4d7d19b955 100644
--- a/doio.c
+++ b/doio.c
@@ -566,7 +566,9 @@ Perl_do_openn(pTHX_ GV *gv, register char *name, I32 len, int as_raw,
 	}
     }
     if (!fp) {
-	if (ckWARN(WARN_NEWLINE) && IoTYPE(io) == IoTYPE_RDONLY && strchr(name, '\n'))
+	if (IoTYPE(io) == IoTYPE_RDONLY && strchr(name, '\n')
+	    && ckWARN(WARN_NEWLINE)
+	)
 	    Perl_warner(aTHX_ packWARN(WARN_NEWLINE), PL_warn_nl, "open");
 	goto say_false;
     }
@@ -1079,7 +1081,7 @@ Perl_do_eof(pTHX_ GV *gv)
 
     if (!io)
 	return TRUE;
-    else if (ckWARN(WARN_IO) && (IoTYPE(io) == IoTYPE_WRONLY))
+    else if ((IoTYPE(io) == IoTYPE_WRONLY) && ckWARN(WARN_IO))
 	report_evil_fh(gv, io, OP_phoney_OUTPUT_ONLY);
 
     while (IoIFP(io)) {
@@ -1392,7 +1394,7 @@ Perl_my_stat(pTHX)
 	s = SvPVX_const(PL_statname);		/* s now NUL-terminated */
 	PL_laststype = OP_STAT;
 	PL_laststatval = PerlLIO_stat(s, &PL_statcache);
-	if (PL_laststatval < 0 && ckWARN(WARN_NEWLINE) && strchr(s, '\n'))
+	if (PL_laststatval < 0 && strchr(s, '\n') && ckWARN(WARN_NEWLINE))
 	    Perl_warner(aTHX_ packWARN(WARN_NEWLINE), PL_warn_nl, "stat");
 	return PL_laststatval;
     }
@@ -1418,8 +1420,8 @@ Perl_my_lstat(pTHX)
 	    return (PL_laststatval = -1);
 	}
     }
-    else if (ckWARN(WARN_IO) && PL_laststype != OP_LSTAT
-	    && (PL_op->op_private & OPpFT_STACKED))
+    else if (PL_laststype != OP_LSTAT
+	    && (PL_op->op_private & OPpFT_STACKED) && ckWARN(WARN_IO))
 	Perl_croak(aTHX_ no_prev_lstat);
 
     PL_laststype = OP_LSTAT;
diff --git a/gv.c b/gv.c
index 823102c7b8..d307124907 100644
--- a/gv.c
+++ b/gv.c
@@ -547,8 +547,9 @@ Perl_gv_autoload4(pTHX_ HV *stash, const char *name, STRLEN len, I32 method)
     /*
      * Inheriting AUTOLOAD for non-methods works ... for now.
      */
-    if (ckWARN2(WARN_DEPRECATED, WARN_SYNTAX) && !method &&
-	(GvCVGEN(gv) || GvSTASH(gv) != stash))
+    if (!method && (GvCVGEN(gv) || GvSTASH(gv) != stash)
+	&& ckWARN2(WARN_DEPRECATED, WARN_SYNTAX)
+    )
 	Perl_warner(aTHX_ packWARN2(WARN_DEPRECATED, WARN_SYNTAX),
 	  "Use of inherited AUTOLOAD for non-method %s::%.*s() is deprecated",
 	     packname, (int)len, name);
diff --git a/op.c b/op.c
index 1caca1425f..b7f560b435 100644
--- a/op.c
+++ b/op.c
@@ -1767,11 +1767,12 @@ Perl_bind_match(pTHX_ I32 type, OP *left, OP *right)
     OP *o;
     bool ismatchop = 0;
 
-    if (ckWARN(WARN_MISC) &&
-      (left->op_type == OP_RV2AV ||
+    if ( (left->op_type == OP_RV2AV ||
        left->op_type == OP_RV2HV ||
        left->op_type == OP_PADAV ||
-       left->op_type == OP_PADHV)) {
+       left->op_type == OP_PADHV)
+       && ckWARN(WARN_MISC))
+    {
       const char *desc = PL_op_desc[(right->op_type == OP_SUBST ||
                             right->op_type == OP_TRANS)
                            ? right->op_type : OP_MATCH];
@@ -1960,8 +1961,8 @@ Perl_localize(pTHX_ OP *o, I32 lex)
 	;
 #endif
     else {
-	if (ckWARN(WARN_PARENTHESIS)
-	    && PL_bufptr > PL_oldbufptr && PL_bufptr[-1] == ',')
+	if ( PL_bufptr > PL_oldbufptr && PL_bufptr[-1] == ','
+	    && ckWARN(WARN_PARENTHESIS))
 	{
 	    char *s = PL_bufptr;
 	    bool sigil = FALSE;
@@ -3528,7 +3529,7 @@ S_new_logop(pTHX_ I32 type, I32 flags, OP** firstp, OP** otherp)
     if (first->op_type == OP_CONST) {
 	if (first->op_private & OPpCONST_STRICT)
 	    no_bareword_allowed(first);
-	else if (ckWARN(WARN_BAREWORD) && (first->op_private & OPpCONST_BARE))
+	else if ((first->op_private & OPpCONST_BARE) && ckWARN(WARN_BAREWORD))
 		Perl_warner(aTHX_ packWARN(WARN_BAREWORD), "Bareword found in conditional");
 	if ((type == OP_AND &&  SvTRUE(((SVOP*)first)->op_sv)) ||
 	    (type == OP_OR  && !SvTRUE(((SVOP*)first)->op_sv)) ||
@@ -3564,8 +3565,8 @@ S_new_logop(pTHX_ I32 type, I32 flags, OP** firstp, OP** otherp)
 	    return first;
 	}
     }
-    else if (ckWARN(WARN_MISC) && (first->op_flags & OPf_KIDS) &&
-             type != OP_DOR) /* [#24076] Don't warn for <FH> err FOO. */
+    else if ((first->op_flags & OPf_KIDS) && type != OP_DOR
+	&& ckWARN(WARN_MISC)) /* [#24076] Don't warn for <FH> err FOO. */
     {
 	const OP *k1 = ((UNOP*)first)->op_first;
 	const OP *k2 = k1->op_sibling;
@@ -6188,7 +6189,7 @@ Perl_ck_split(pTHX_ OP *o)
     kid->op_type = OP_PUSHRE;
     kid->op_ppaddr = PL_ppaddr[OP_PUSHRE];
     scalar(kid);
-    if (ckWARN(WARN_REGEXP) && ((PMOP *)kid)->op_pmflags & PMf_GLOBAL) {
+    if (((PMOP *)kid)->op_pmflags & PMf_GLOBAL && ckWARN(WARN_REGEXP)) {
       Perl_warner(aTHX_ packWARN(WARN_REGEXP),
                   "Use of /g modifier is meaningless in split");
     }
@@ -6214,9 +6215,9 @@ Perl_ck_split(pTHX_ OP *o)
 OP *
 Perl_ck_join(pTHX_ OP *o)
 {
-    if (ckWARN(WARN_SYNTAX)) {
-	const OP *kid = cLISTOPo->op_first->op_sibling;
-	if (kid && kid->op_type == OP_MATCH) {
+    const OP *kid = cLISTOPo->op_first->op_sibling;
+    if (kid && kid->op_type == OP_MATCH) {
+	if (ckWARN(WARN_SYNTAX)) {
             const REGEXP *re = PM_GETRE(kPMOP);
 	    const char *pmstr = re ? re->precomp : "STRING";
 	    Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
@@ -6267,7 +6268,7 @@ Perl_ck_subr(pTHX_ OP *o)
 		    }
 		    else {
 			delete_op = 1;
-			if (ckWARN(WARN_ASSERTIONS) && !(PL_hints & HINT_ASSERTIONSSEEN)) {
+			if (!(PL_hints & HINT_ASSERTIONSSEEN) && ckWARN(WARN_ASSERTIONS)) {
 			    Perl_warner(aTHX_ packWARN(WARN_ASSERTIONS),
 					"Impossible to activate assertion call");
 			}
@@ -6739,8 +6740,9 @@ Perl_peep(pTHX_ register OP *o)
 
 	case OP_EXEC:
 	    o->op_opt = 1;
-	    if (ckWARN(WARN_SYNTAX) && o->op_next
-		&& o->op_next->op_type == OP_NEXTSTATE) {
+	    if (o->op_next && o->op_next->op_type == OP_NEXTSTATE
+		&& ckWARN(WARN_SYNTAX))
+	    {
 		if (o->op_next->op_sibling &&
 			o->op_next->op_sibling->op_type != OP_EXIT &&
 			o->op_next->op_sibling->op_type != OP_WARN &&
diff --git a/pad.c b/pad.c
index 5f04fd63b3..f60aeaf6dd 100644
--- a/pad.c
+++ b/pad.c
@@ -501,7 +501,7 @@ Perl_pad_check_dup(pTHX_ const char *name, bool is_our, const HV *ourstash)
     PADOFFSET	top, off;
 
     ASSERT_CURPAD_ACTIVE("pad_check_dup");
-    if (!ckWARN(WARN_MISC) || AvFILLp(PL_comppad_name) < 0)
+    if (AvFILLp(PL_comppad_name) < 0 || !ckWARN(WARN_MISC))
 	return; /* nothing to check */
 
     svp = AvARRAY(PL_comppad_name);
diff --git a/perlio.c b/perlio.c
index 2276f4c339..9cd24d2bf9 100644
--- a/perlio.c
+++ b/perlio.c
@@ -979,7 +979,6 @@ PerlIO_parse_layers(pTHX_ PerlIO_list_t *av, const char *names)
 		    }
 		}
 		if (e > s) {
-		    const bool warn_layer = ckWARN(WARN_LAYER);
 		    PerlIO_funcs *layer =
 			PerlIO_find_layer(aTHX_ s, llen, 1);
 		    if (layer) {
@@ -989,7 +988,7 @@ PerlIO_parse_layers(pTHX_ PerlIO_list_t *av, const char *names)
 					 &PL_sv_undef);
 		    }
 		    else {
-			if (warn_layer)
+			if (ckWARN(WARN_LAYER))
 			    Perl_warner(aTHX_ packWARN(WARN_LAYER), "Unknown PerlIO layer \"%.*s\"",
 				  (int) llen, s);
 			return -1;
diff --git a/pp.c b/pp.c
index 039aeba63b..cb48bb86a4 100644
--- a/pp.c
+++ b/pp.c
@@ -531,7 +531,7 @@ PP(pp_bless)
 	if (ssv && !SvGMAGICAL(ssv) && !SvAMAGIC(ssv) && SvROK(ssv))
 	    Perl_croak(aTHX_ "Attempt to bless into a reference");
 	ptr = SvPV_const(ssv,len);
-	if (ckWARN(WARN_MISC) && len == 0)
+	if (len == 0 && ckWARN(WARN_MISC))
 	    Perl_warner(aTHX_ packWARN(WARN_MISC),
 		   "Explicit blessing to '' (assuming package main)");
 	stash = gv_stashpvn(ptr, len, TRUE);
@@ -789,7 +789,7 @@ PP(pp_undef)
 	hv_undef((HV*)sv);
 	break;
     case SVt_PVCV:
-	if (ckWARN(WARN_MISC) && cv_const_sv((CV*)sv))
+	if (cv_const_sv((CV*)sv) && ckWARN(WARN_MISC))
 	    Perl_warner(aTHX_ packWARN(WARN_MISC), "Constant subroutine %s undefined",
 		 CvANON((CV*)sv) ? "(anonymous)" : GvENAME(CvGV((CV*)sv)));
 	/* FALL THROUGH */
diff --git a/pp_hot.c b/pp_hot.c
index b4b73ad566..07eb58553c 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -1494,8 +1494,9 @@ Perl_do_readline(pTHX)
 	}
     }
     if (!fp) {
-	if (ckWARN2(WARN_GLOB, WARN_CLOSED)
-		&& (!io || !(IoFLAGS(io) & IOf_START))) {
+	if ((!io || !(IoFLAGS(io) & IOf_START))
+	    && ckWARN2(WARN_GLOB, WARN_CLOSED))
+	{
 	    if (type == OP_GLOB)
 		Perl_warner(aTHX_ packWARN(WARN_GLOB),
 			    "glob failed (can't start child: %s)",
@@ -1610,8 +1611,8 @@ Perl_do_readline(pTHX)
 	     const STRLEN len = SvCUR(sv) - offset;
 	     const U8 *f;
 	     
-	     if (ckWARN(WARN_UTF8) &&
-		 !Perl_is_utf8_string_loc(aTHX_ s, len, &f))
+	     if (!Perl_is_utf8_string_loc(aTHX_ s, len, &f)
+	        && ckWARN(WARN_UTF8))
 		  /* Emulate :encoding(utf8) warning in the same case. */
 		  Perl_warner(aTHX_ packWARN(WARN_UTF8),
 			      "utf8 \"\\x%02X\" does not map to Unicode",
diff --git a/pp_pack.c b/pp_pack.c
index 2bcb731f68..63a60f190e 100644
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -1024,8 +1024,7 @@ S_next_symbol(pTHX_ tempsym_t* symptr )
           Perl_croak(aTHX_ "Can't use '%c' in a group with different byte-order in %s",
                      *patptr, _action( symptr ) );
 
-        if (ckWARN(WARN_UNPACK)) {
-          if (code & modifier)
+        if ((code & modifier) && ckWARN(WARN_UNPACK)) {
 	    Perl_warner(aTHX_ packWARN(WARN_UNPACK),
                         "Duplicate modifier '%c' after '%c' in %s",
                         *patptr, (int) TYPE_NO_MODIFIERS(code),
@@ -2518,6 +2517,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
     I32 items  = endlist - beglist;
     bool found = next_symbol(symptr);
     bool utf8 = (symptr->flags & FLAG_PARSE_UTF8) ? 1 : 0;
+    bool warn_utf8 = ckWARN(WARN_UTF8);
 
     if (symptr->level == 0 && found && symptr->code == 'U') {
 	marked_upgrade(aTHX_ cat, symptr);
@@ -2843,7 +2843,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
 	    end = str + fromlen;
 	    if (DO_UTF8(fromstr)) {
 		utf8_source = TRUE;
-		utf8_flags  = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
+		utf8_flags  = warn_utf8 ? 0 : UTF8_ALLOW_ANY;
 	    } else {
 		utf8_source = FALSE;
 		utf8_flags  = 0; /* Unused, but keep compilers happy */
@@ -2912,7 +2912,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
 	    end = str + fromlen;
 	    if (DO_UTF8(fromstr)) {
 		utf8_source = TRUE;
-		utf8_flags  = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
+		utf8_flags  = warn_utf8 ? 0 : UTF8_ALLOW_ANY;
 	    } else {
 		utf8_source = FALSE;
 		utf8_flags  = 0; /* Unused, but keep compilers happy */
@@ -3025,7 +3025,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
 		    }
 		    cur = (char *) uvuni_to_utf8_flags((U8 *) cur,
 						       NATIVE_TO_UNI(auv),
-						       ckWARN(WARN_UTF8) ?
+						       warn_utf8 ?
 						       0 : UNICODE_ALLOW_ANY);
 		} else {
 		    if (auv >= 0x100) {
@@ -3079,7 +3079,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
 		if (utf8) {
 		    U8 buffer[UTF8_MAXLEN], *endb;
 		    endb = uvuni_to_utf8_flags(buffer, auv,
-					       ckWARN(WARN_UTF8) ?
+					       warn_utf8 ?
 					       0 : UNICODE_ALLOW_ANY);
 		    if (cur+(endb-buffer)*UTF8_EXPAND >= end) {
 			*cur = '\0';
@@ -3097,7 +3097,7 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
 			end = start+SvLEN(cat)-UTF8_MAXLEN;
 		    }
 		    cur = (char *) uvuni_to_utf8_flags((U8 *) cur, auv,
-						       ckWARN(WARN_UTF8) ?
+						       warn_utf8 ?
 						       0 : UNICODE_ALLOW_ANY);
 		}
 	    }
@@ -3524,9 +3524,8 @@ S_pack_rec(pTHX_ SV *cat, tempsym_t* symptr, SV **beglist, SV **endlist )
 		     * of pack() (and all copies of the result) are
 		     * gone.
 		     */
-		    if (ckWARN(WARN_PACK) &&
-			(SvTEMP(fromstr) || (SvPADTMP(fromstr) &&
-					     !SvREADONLY(fromstr)))) {
+		    if ((SvTEMP(fromstr) || (SvPADTMP(fromstr) &&
+			     !SvREADONLY(fromstr))) && ckWARN(WARN_PACK)) {
 			Perl_warner(aTHX_ packWARN(WARN_PACK),
 				    "Attempt to pack pointer to temporary value");
 		    }
diff --git a/pp_sys.c b/pp_sys.c
index b126647d8b..2d1752bf1b 100644
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -907,8 +907,7 @@ PP(pp_untie)
 	       LEAVE;
 	       SPAGAIN;
             }
-           else if (ckWARN(WARN_UNTIE)) {
-	       if (mg && SvREFCNT(obj) > 1)
+	    else if (mg && SvREFCNT(obj) > 1 && ckWARN(WARN_UNTIE)) {
 		  Perl_warner(aTHX_ packWARN(WARN_UNTIE),
 		      "untie attempted while %"UVuf" inner references still exist",
 		       (UV)SvREFCNT(obj) - 1 ) ;
@@ -1232,8 +1231,8 @@ PP(pp_getc)
 	RETURN;
     }
     if (!gv || do_eof(gv)) { /* make sure we have fp with something */
-	if (ckWARN2(WARN_UNOPENED,WARN_CLOSED)
-		&& (!io || (!IoIFP(io) && IoTYPE(io) != IoTYPE_WRONLY)))
+	if ((!io || (!IoIFP(io) && IoTYPE(io) != IoTYPE_WRONLY))
+	  && ckWARN2(WARN_UNOPENED,WARN_CLOSED))
 	    report_evil_fh(gv, io, PL_op->op_type);
 	SETERRNO(EBADF,RMS_IFI);
 	RETPUSHUNDEF;
diff --git a/regcomp.c b/regcomp.c
index eab68b337d..e38a5723c3 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -2202,12 +2202,12 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp, I32 *deltap, reg
 		}
 		if (!scan) 		/* It was not CURLYX, but CURLY. */
 		    scan = next;
-		if (ckWARN(WARN_REGEXP)
-		       /* ? quantifier ok, except for (?{ ... }) */
-		    && (next_is_eval || !(mincount == 0 && maxcount == 1))
+		if ( /* ? quantifier ok, except for (?{ ... }) */
+		    (next_is_eval || !(mincount == 0 && maxcount == 1))
 		    && (minnext == 0) && (deltanext == 0)
 		    && data && !(data->flags & (SF_HAS_PAR|SF_IN_PAR))
-		    && maxcount <= REG_INFTY/3) /* Complement check for big count */
+		    && maxcount <= REG_INFTY/3 /* Complement check for big count */
+		    && ckWARN(WARN_REGEXP))
 		{
 		    vWARN(RExC_parse,
 			  "Quantifier unexpected on zero-length expression");
@@ -3838,7 +3838,7 @@ S_regpiece(pTHX_ RExC_state_t *pRExC_state, I32 *flagp)
 	goto do_curly;
     }
   nest_check:
-    if (ckWARN(WARN_REGEXP) && !SIZE_ONLY && !(flags&HASWIDTH) && max > REG_INFTY/3) {
+    if (!SIZE_ONLY && !(flags&HASWIDTH) && max > REG_INFTY/3 && ckWARN(WARN_REGEXP)) {
 	vWARN3(RExC_parse,
 	       "%.*s matches null string many times",
 	       RExC_parse - origparse,
@@ -4275,7 +4275,7 @@ tryagain:
 			    FAIL("Trailing \\");
 			/* FALL THROUGH */
 		    default:
-			if (!SIZE_ONLY && ckWARN(WARN_REGEXP) && isALPHA(*p))
+			if (!SIZE_ONLY&& isALPHA(*p) && ckWARN(WARN_REGEXP))
 			    vWARN2(p + 1, "Unrecognized escape \\%c passed through", UCHARAT(p));
 			goto normal_default;
 		    }
@@ -4818,7 +4818,7 @@ S_regclass(pTHX_ RExC_state_t *pRExC_state)
 		break;
             }
 	    default:
-		if (!SIZE_ONLY && ckWARN(WARN_REGEXP) && isALPHA(value))
+		if (!SIZE_ONLY && isALPHA(value) && ckWARN(WARN_REGEXP))
 		    vWARN2(RExC_parse,
 			   "Unrecognized escape \\%c in character class passed through",
 			   (int)value);
diff --git a/regexec.c b/regexec.c
index 6a644d978a..c764c373c8 100644
--- a/regexec.c
+++ b/regexec.c
@@ -1039,14 +1039,15 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
 		U8 *sm = (U8 *) m;
 		U8 tmpbuf1[UTF8_MAXBYTES_CASE+1];
 		U8 tmpbuf2[UTF8_MAXBYTES_CASE+1];
+		const U32 uniflags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
 
 		to_utf8_lower((U8*)m, tmpbuf1, &ulen1);
 		to_utf8_upper((U8*)m, tmpbuf2, &ulen2);
 
 		c1 = utf8n_to_uvchr(tmpbuf1, UTF8_MAXBYTES_CASE, 
-				    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
+				    0, uniflags);
 		c2 = utf8n_to_uvchr(tmpbuf2, UTF8_MAXBYTES_CASE,
-				    0, ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY);
+				    0, uniflags);
 		lnc = 0;
 		while (sm < ((U8 *) m + ln)) {
 		    lnc++;
@@ -1085,14 +1086,13 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
 	        UV c, f;
 	        U8 tmpbuf [UTF8_MAXBYTES+1];
 		STRLEN len, foldlen;
-		
+		const U32 uniflags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
 		if (c1 == c2) {
 		    /* Upper and lower of 1st char are equal -
 		     * probably not a "letter". */
 		    while (s <= e) {
 		        c = utf8n_to_uvchr((U8*)s, UTF8_MAXBYTES, &len,
-					   ckWARN(WARN_UTF8) ?
-					   0 : UTF8_ALLOW_ANY);
+					   uniflags);
 			if ( c == c1
 			     && (ln == len ||
 				 ibcmp_utf8(s, (char **)0, 0,  do_utf8,
@@ -1119,8 +1119,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
 		else {
 		    while (s <= e) {
 		      c = utf8n_to_uvchr((U8*)s, UTF8_MAXBYTES, &len,
-					   ckWARN(WARN_UTF8) ?
-					   0 : UTF8_ALLOW_ANY);
+					   uniflags);
 
 			/* Handle some of the three Greek sigmas cases.
 			 * Note that not all the possible combinations
@@ -2416,6 +2415,7 @@ S_regmatch(pTHX_ regnode *prog)
 
     SV *re_debug_flags = NULL;
 #endif
+    U32 uniflags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
 
     GET_RE_DEBUG_FLAGS;
 
@@ -2583,8 +2583,6 @@ S_regmatch(pTHX_ regnode *prog)
 	case TRIEF:
 	case TRIEFL:
 	    {
-
-		const U32 uniflags = ckWARN( WARN_UTF8 ) ? 0 : UTF8_ALLOW_ANY;
 		U8 *uc = ( U8* )locinput;
 		U32 state = 1;
 		U16 charid = 0;
@@ -2652,7 +2650,6 @@ S_regmatch(pTHX_ regnode *prog)
 	       from previous if blocks */
 	case TRIE:
 	    {
-		const U32 uniflags = ckWARN( WARN_UTF8 ) ? 0 : UTF8_ALLOW_ANY;
 		U8 *uc = (U8*)locinput;
 		U32 state = 1;
 		U16 charid = 0;
@@ -2808,8 +2805,7 @@ S_regmatch(pTHX_ regnode *prog)
 			     sayNO;
 			if (NATIVE_TO_UNI(*(U8*)s) !=
 			    utf8n_to_uvuni((U8*)l, UTF8_MAXBYTES, &ulen,
-					   ckWARN(WARN_UTF8) ?
-					   0 : UTF8_ALLOW_ANY))
+					    uniflags))
 			     sayNO;
 			l += ulen;
 			s ++;
@@ -2823,8 +2819,7 @@ S_regmatch(pTHX_ regnode *prog)
 			    sayNO;
 			if (NATIVE_TO_UNI(*((U8*)l)) !=
 			    utf8n_to_uvuni((U8*)s, UTF8_MAXBYTES, &ulen,
-					   ckWARN(WARN_UTF8) ?
-					   0 : UTF8_ALLOW_ANY))
+					   uniflags))
 			    sayNO;
 			s += ulen;
 			l ++;
@@ -3941,16 +3936,13 @@ S_regmatch(pTHX_ regnode *prog)
 			     to_utf8_upper((U8*)s, tmpbuf2, &ulen2);
 
 			     c1 = utf8n_to_uvuni(tmpbuf1, UTF8_MAXBYTES, 0,
-						 ckWARN(WARN_UTF8) ?
-						 0 : UTF8_ALLOW_ANY);
+						 uniflags);
 			     c2 = utf8n_to_uvuni(tmpbuf2, UTF8_MAXBYTES, 0,
-						 ckWARN(WARN_UTF8) ?
-						 0 : UTF8_ALLOW_ANY);
+						 uniflags);
 			}
 			else {
 			    c2 = c1 = utf8n_to_uvchr(s, UTF8_MAXBYTES, 0,
-						     ckWARN(WARN_UTF8) ?
-						     0 : UTF8_ALLOW_ANY);
+						     uniflags);
 			}
 		    }
 		}
@@ -4011,8 +4003,7 @@ S_regmatch(pTHX_ regnode *prog)
 				while (locinput <= e &&
 				       utf8n_to_uvchr((U8*)locinput,
 						      UTF8_MAXBYTES, &len,
-						      ckWARN(WARN_UTF8) ?
-						      0 : UTF8_ALLOW_ANY) != (UV)c1) {
+						      uniflags) != (UV)c1) {
 				    locinput += len;
 				    count++;
 				}
@@ -4023,8 +4014,7 @@ S_regmatch(pTHX_ regnode *prog)
 				while (locinput <= e) {
 				    UV c = utf8n_to_uvchr((U8*)locinput,
 							  UTF8_MAXBYTES, &len,
-							  ckWARN(WARN_UTF8) ?
-							  0 : UTF8_ALLOW_ANY);
+							  uniflags);
 				    if (c == (UV)c1 || c == (UV)c2)
 					break;
 				    locinput += len;
@@ -4060,8 +4050,7 @@ S_regmatch(pTHX_ regnode *prog)
 			if (do_utf8)
 			    c = utf8n_to_uvchr((U8*)PL_reginput,
 					       UTF8_MAXBYTES, 0,
-					       ckWARN(WARN_UTF8) ?
-					       0 : UTF8_ALLOW_ANY);
+					       uniflags);
 			else
 			    c = UCHARAT(PL_reginput);
 			/* If it could work, try it. */
@@ -4110,8 +4099,7 @@ S_regmatch(pTHX_ regnode *prog)
 			    if (do_utf8)
 				c = utf8n_to_uvchr((U8*)PL_reginput,
 						   UTF8_MAXBYTES, 0,
-						   ckWARN(WARN_UTF8) ?
-						   0 : UTF8_ALLOW_ANY);
+						   uniflags);
 			    else
 				c = UCHARAT(PL_reginput);
 			}
@@ -4133,8 +4121,7 @@ S_regmatch(pTHX_ regnode *prog)
 			    if (do_utf8)
 				c = utf8n_to_uvchr((U8*)PL_reginput,
 						   UTF8_MAXBYTES, 0,
-						   ckWARN(WARN_UTF8) ?
-						   0 : UTF8_ALLOW_ANY);
+						   uniflags);
 			    else
 				c = UCHARAT(PL_reginput);
 			}
diff --git a/sv.c b/sv.c
index 4e25290153..fd77ada7c9 100644
--- a/sv.c
+++ b/sv.c
@@ -2113,7 +2113,7 @@ Perl_sv_2iv_flags(pTHX_ register SV *sv, I32 flags)
 	    return asIV(sv);
 	if (!SvROK(sv)) {
 	    if (!(SvFLAGS(sv) & SVs_PADTMP)) {
-		if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing)
+		if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
 		    report_uninit(sv);
 	    }
 	    return 0;
@@ -2373,7 +2373,7 @@ Perl_sv_2iv_flags(pTHX_ register SV *sv, I32 flags)
 #endif /* NV_PRESERVES_UV */
 	}
     } else  {
-	if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP))
+	if (!PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP) && ckWARN(WARN_UNINITIALIZED))
 	    report_uninit(sv);
 	if (SvTYPE(sv) < SVt_IV)
 	    /* Typically the caller expects that sv_any is not NULL now.  */
@@ -2421,7 +2421,7 @@ Perl_sv_2uv_flags(pTHX_ register SV *sv, I32 flags)
 	    return asUV(sv);
 	if (!SvROK(sv)) {
 	    if (!(SvFLAGS(sv) & SVs_PADTMP)) {
-		if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing)
+		if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
 		    report_uninit(sv);
 	    }
 	    return 0;
@@ -2662,7 +2662,7 @@ Perl_sv_2uv_flags(pTHX_ register SV *sv, I32 flags)
     }
     else  {
 	if (!(SvFLAGS(sv) & SVs_PADTMP)) {
-	    if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing)
+	    if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
 		report_uninit(sv);
 	}
 	if (SvTYPE(sv) < SVt_IV)
@@ -2696,7 +2696,7 @@ Perl_sv_2nv(pTHX_ register SV *sv)
 	if (SvNOKp(sv))
 	    return SvNVX(sv);
 	if (SvPOKp(sv) && SvLEN(sv)) {
-	    if (ckWARN(WARN_NUMERIC) && !SvIOKp(sv) &&
+	    if (!SvIOKp(sv) && ckWARN(WARN_NUMERIC) &&
 		!grok_number(SvPVX_const(sv), SvCUR(sv), NULL))
 		not_a_number(sv);
 	    return Atof(SvPVX_const(sv));
@@ -2709,7 +2709,7 @@ Perl_sv_2nv(pTHX_ register SV *sv)
 	}	
         if (!SvROK(sv)) {
 	    if (!(SvFLAGS(sv) & SVs_PADTMP)) {
-		if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing)
+		if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
 		    report_uninit(sv);
 	    }
             return (NV)0;
@@ -2776,7 +2776,7 @@ Perl_sv_2nv(pTHX_ register SV *sv)
     else if (SvPOKp(sv) && SvLEN(sv)) {
 	UV value;
 	const int numtype = grok_number(SvPVX_const(sv), SvCUR(sv), &value);
-	if (ckWARN(WARN_NUMERIC) && !SvIOKp(sv) && !numtype)
+	if (!SvIOKp(sv) && !numtype && ckWARN(WARN_NUMERIC))
 	    not_a_number(sv);
 #ifdef NV_PRESERVES_UV
 	if ((numtype & (IS_NUMBER_IN_UV | IS_NUMBER_NOT_INT))
@@ -2858,7 +2858,7 @@ Perl_sv_2nv(pTHX_ register SV *sv)
 #endif /* NV_PRESERVES_UV */
     }
     else  {
-	if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP))
+	if (!PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP) && ckWARN(WARN_UNINITIALIZED))
 	    report_uninit(sv);
 	if (SvTYPE(sv) < SVt_NV)
 	    /* Typically the caller expects that sv_any is not NULL now.  */
@@ -3043,7 +3043,7 @@ Perl_sv_2pv_flags(pTHX_ register SV *sv, STRLEN *lp, I32 flags)
 	}
         if (!SvROK(sv)) {
 	    if (!(SvFLAGS(sv) & SVs_PADTMP)) {
-		if (ckWARN(WARN_UNINITIALIZED) && !PL_localizing)
+		if (!PL_localizing && ckWARN(WARN_UNINITIALIZED))
 		    report_uninit(sv);
 	    }
 	    if (lp)
@@ -3268,8 +3268,7 @@ Perl_sv_2pv_flags(pTHX_ register SV *sv, STRLEN *lp, I32 flags)
 #endif
     }
     else {
-	if (ckWARN(WARN_UNINITIALIZED)
-	    && !PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP))
+	if (!PL_localizing && !(SvFLAGS(sv) & SVs_PADTMP) && ckWARN(WARN_UNINITIALIZED))
 	    report_uninit(sv);
 	if (lp)
 	*lp = 0;
@@ -9690,8 +9689,10 @@ Perl_sv_vcatpvfn(pTHX_ SV *sv, const char *pat, STRLEN patlen, va_list *args, SV
 
 	default:
       unknown:
-	    if (!args && ckWARN(WARN_PRINTF) &&
-		  (PL_op->op_type == OP_PRTF || PL_op->op_type == OP_SPRINTF)) {
+	    if (!args
+		&& (PL_op->op_type == OP_PRTF || PL_op->op_type == OP_SPRINTF)
+		&& ckWARN(WARN_PRINTF))
+	    {
 		SV *msg = sv_newmortal();
 		Perl_sv_setpvf(aTHX_ msg, "Invalid conversion in %sprintf: ",
 			  (PL_op->op_type == OP_PRTF) ? "" : "s");
diff --git a/toke.c b/toke.c
index 780855e049..33ec2c460e 100644
--- a/toke.c
+++ b/toke.c
@@ -1555,9 +1555,9 @@ S_scan_const(pTHX_ char *start)
 		/* FALL THROUGH */
 	    default:
 	        {
-		    if (ckWARN(WARN_MISC) &&
-			isALNUM(*s) &&
-			*s != '_')
+		    if (isALNUM(*s) &&
+			*s != '_' &&
+			ckWARN(WARN_MISC))
 			Perl_warner(aTHX_ packWARN(WARN_MISC),
 			       "Unrecognized escape \\%c passed through",
 			       *s);
@@ -3479,8 +3479,8 @@ Perl_yylex(pTHX)
 	    AOPERATOR(ANDAND);
 	s--;
 	if (PL_expect == XOPERATOR) {
-	    if (ckWARN(WARN_SEMICOLON)
-		&& isIDFIRST_lazy_if(s,UTF) && PL_bufptr == PL_linestart)
+	    if (PL_bufptr == PL_linestart && ckWARN(WARN_SEMICOLON)
+		&& isIDFIRST_lazy_if(s,UTF))
 	    {
 		CopLINE_dec(PL_curcop);
 		Perl_warner(aTHX_ packWARN(WARN_SEMICOLON), PL_warn_nosemi);
@@ -3515,7 +3515,7 @@ Perl_yylex(pTHX)
 	    OPERATOR(',');
 	if (tmp == '~')
 	    PMop(OP_MATCH);
-	if (ckWARN(WARN_SYNTAX) && tmp && isSPACE(*s) && strchr("+-*/%.^&|<",tmp))
+	if (tmp && isSPACE(*s) && strchr("+-*/%.^&|<",tmp) && ckWARN(WARN_SYNTAX))
 	    Perl_warner(aTHX_ packWARN(WARN_SYNTAX), "Reversed %c= operator",(int)tmp);
 	s--;
 	if (PL_expect == XSTATE && isALPHA(tmp) &&
@@ -3685,8 +3685,8 @@ Perl_yylex(pTHX)
 	    else if (*s == '{') {
 		char *t;
 		PL_tokenbuf[0] = '%';
-		if (ckWARN(WARN_SYNTAX) && strEQ(PL_tokenbuf+1, "SIG") &&
-		    (t = strchr(s, '}')) && (t = strchr(t, '=')))
+		if (strEQ(PL_tokenbuf+1, "SIG") && (t = strchr(s, '}'))
+		    && (t = strchr(t, '=')) && ckWARN(WARN_SYNTAX))
 		{
 		    char tmpbuf[sizeof PL_tokenbuf];
 		    for (t++; isSPACE(*t); t++) ;
@@ -3766,8 +3766,8 @@ Perl_yylex(pTHX)
 		PL_tokenbuf[0] = '%';
 
 	    /* Warn about @ where they meant $. */
-	    if (ckWARN(WARN_SYNTAX)) {
-		if (*s == '[' || *s == '{') {
+	    if (*s == '[' || *s == '{') {
+		if (ckWARN(WARN_SYNTAX)) {
 		    const char *t = s + 1;
 		    while (*t && (isALNUM_lazy_if(t,UTF) || strchr(" \t$#+-'\"", *t)))
 			t++;
@@ -3920,7 +3920,7 @@ Perl_yylex(pTHX)
 
     case '\\':
 	s++;
-	if (ckWARN(WARN_SYNTAX) && PL_lex_inwhat && isDIGIT(*s))
+	if (PL_lex_inwhat && isDIGIT(*s) && ckWARN(WARN_SYNTAX))
 	    Perl_warner(aTHX_ packWARN(WARN_SYNTAX),"Can't use \\%c to mean $%c in expression",
 			*s, *s);
 	if (PL_expect == XOPERATOR)
@@ -4081,8 +4081,8 @@ Perl_yylex(pTHX)
 		}
 		gv = Nullgv;
 		gvp = 0;
-		if (ckWARN(WARN_AMBIGUOUS) && hgv
-		    && tmp != KEY_x && tmp != KEY_CORE)	/* never ambiguous */
+		if (hgv && tmp != KEY_x && tmp != KEY_CORE
+			&& ckWARN(WARN_AMBIGUOUS))	/* never ambiguous */
 		    Perl_warner(aTHX_ packWARN(WARN_AMBIGUOUS),
 		    	"Ambiguous call resolved as CORE::%s(), %s",
 			 GvENAME(hgv), "qualify as such or use &");
@@ -4300,8 +4300,8 @@ Perl_yylex(pTHX)
 		    yylval.opval->op_private |= OPpCONST_STRICT;
 		else {
 		bareword:
-		    if (ckWARN(WARN_RESERVED)) {
-			if (lastchar != '-') {
+		    if (lastchar != '-') {
+			if (ckWARN(WARN_RESERVED)) {
 			    for (d = PL_tokenbuf; *d && isLOWER(*d); d++) ;
 			    if (!*d && !gv_stashpv(PL_tokenbuf,FALSE))
 				Perl_warner(aTHX_ packWARN(WARN_RESERVED), PL_warn_reserved,
@@ -9281,8 +9281,8 @@ S_scan_pat(pTHX_ char *start, I32 type)
 	    pmflag(&pm->op_pmflags,*s++);
     }
     /* issue a warning if /c is specified,but /g is not */
-    if (ckWARN(WARN_REGEXP) &&
-        (pm->op_pmflags & PMf_CONTINUE) && !(pm->op_pmflags & PMf_GLOBAL))
+    if ((pm->op_pmflags & PMf_CONTINUE) && !(pm->op_pmflags & PMf_GLOBAL)
+	    && ckWARN(WARN_REGEXP))
     {
         Perl_warner(aTHX_ packWARN(WARN_REGEXP), c_without_g);
     }
@@ -9337,7 +9337,7 @@ S_scan_subst(pTHX_ char *start)
     }
 
     /* /c is not meaningful with s/// */
-    if (ckWARN(WARN_REGEXP) && (pm->op_pmflags & PMf_CONTINUE))
+    if ((pm->op_pmflags & PMf_CONTINUE) && ckWARN(WARN_REGEXP))
     {
         Perl_warner(aTHX_ packWARN(WARN_REGEXP), c_in_subst);
     }
@@ -10223,7 +10223,7 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 
 		/* _ are ignored -- but warned about if consecutive */
 		case '_':
-		    if (ckWARN(WARN_SYNTAX) && lastub && s == lastub + 1)
+		    if (lastub && s == lastub + 1 && ckWARN(WARN_SYNTAX))
 		        Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 				    "Misplaced _ in number");
 		    lastub = s++;
@@ -10303,7 +10303,7 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 
 	    sv = NEWSV(92,0);
 	    if (overflowed) {
-		if (ckWARN(WARN_PORTABLE) && n > 4294967295.0)
+		if (n > 4294967295.0 && ckWARN(WARN_PORTABLE))
 		    Perl_warner(aTHX_ packWARN(WARN_PORTABLE),
 				"%s number > %s non-portable",
 				Base, max);
@@ -10311,7 +10311,7 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 	    }
 	    else {
 #if UVSIZE > 4
-		if (ckWARN(WARN_PORTABLE) && u > 0xffffffff)
+		if (u > 0xffffffff && ckWARN(WARN_PORTABLE))
 		    Perl_warner(aTHX_ packWARN(WARN_PORTABLE),
 				"%s number > %s non-portable",
 				Base, max);
@@ -10343,7 +10343,7 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 	       if -w is on
 	    */
 	    if (*s == '_') {
-		if (ckWARN(WARN_SYNTAX) && lastub && s == lastub + 1)
+		if (lastub && s == lastub + 1 && ckWARN(WARN_SYNTAX))
 		    Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 				"Misplaced _ in number");
 		lastub = s++;
@@ -10385,7 +10385,7 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 		if (d >= e)
 		    Perl_croak(aTHX_ number_too_long);
 		if (*s == '_') {
-		   if (ckWARN(WARN_SYNTAX) && lastub && s == lastub + 1)
+		   if (lastub && s == lastub + 1 && ckWARN(WARN_SYNTAX))
 		       Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 				   "Misplaced _ in number");
 		   lastub = s;
@@ -10442,9 +10442,9 @@ Perl_scan_num(pTHX_ const char *start, YYSTYPE* lvalp)
 		    *d++ = *s++;
 		}
 		else {
-		   if (ckWARN(WARN_SYNTAX) &&
-		       ((lastub && s == lastub + 1) ||
-			(!isDIGIT(s[1]) && s[1] != '_')))
+		   if (((lastub && s == lastub + 1) ||
+			(!isDIGIT(s[1]) && s[1] != '_'))
+	   	    && ckWARN(WARN_SYNTAX))
 		       Perl_warner(aTHX_ packWARN(WARN_SYNTAX),
 				   "Misplaced _ in number");
 		   lastub = s++;