From df91b2c56ff1b711bacf43bb03807cfa68f46eb0 Mon Sep 17 00:00:00 2001
From: "Adrian M. Enache" <enache@rdslink.ro>
Date: Mon, 22 Dec 2003 23:22:12 +0000
Subject: [PATCH] re-fix [perl #24508] without speed regression. keep an eye on
 this.

p4raw-id: //depot/perl@21951
---
 op.c      | 20 +++++++++++++++++++-
 opcode.h  |  2 +-
 opcode.pl |  2 +-
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/op.c b/op.c
index 020f463..806c07f 100644
--- a/op.c
+++ b/op.c
@@ -4715,7 +4715,8 @@ OP *
 Perl_ck_concat(pTHX_ OP *o)
 {
     OP *kid = cUNOPo->op_first;
-    if (kid->op_type == OP_CONCAT && !(kUNOP->op_first->op_flags & OPf_MOD))
+    if (kid->op_type == OP_CONCAT && !(kid->op_private & OPpTARGET_MY) &&
+	    !(kUNOP->op_first->op_flags & OPf_MOD))
         o->op_flags |= OPf_STACKED;
     return o;
 }
@@ -6264,6 +6265,23 @@ Perl_peep(pTHX_ register OP *o)
 	    o->op_seq = PL_op_seqmax++;
 	    break;
 
+	case OP_CONCAT:
+	    if (o->op_next && o->op_next->op_type == OP_STRINGIFY) {
+		if (o->op_next->op_private & OPpTARGET_MY) {
+		    if (o->op_flags & OPf_STACKED) /* chained concats */
+			goto ignore_optimization;
+		    else {
+			/* assert(PL_opargs[o->op_type] & OA_TARGLEX); */
+			o->op_targ = o->op_next->op_targ;
+			o->op_next->op_targ = 0;
+			o->op_private |= OPpTARGET_MY;
+		    }
+		}
+		op_null(o->op_next);
+	    }
+	  ignore_optimization:
+	    o->op_seq = PL_op_seqmax++;
+	    break;
 	case OP_STUB:
 	    if ((o->op_flags & OPf_WANT) != OPf_WANT_LIST) {
 		o->op_seq = PL_op_seqmax++;
diff --git a/opcode.h b/opcode.h
index 4d41ddf..4de3dee 100644
--- a/opcode.h
+++ b/opcode.h
@@ -1544,7 +1544,7 @@ EXT U32 PL_opargs[] = {
 	0x0002251e,	/* i_add */
 	0x0002252e,	/* subtract */
 	0x0002251e,	/* i_subtract */
-	0x0002240e,	/* concat */
+	0x0002250e,	/* concat */
 	0x0000290e,	/* stringify */
 	0x0002250e,	/* left_shift */
 	0x0002250e,	/* right_shift */
diff --git a/opcode.pl b/opcode.pl
index 270e154..e13d14d 100755
--- a/opcode.pl
+++ b/opcode.pl
@@ -537,7 +537,7 @@ add		addition (+)		ck_null		IfsT2	S S
 i_add		integer addition (+)	ck_null		ifsT2	S S
 subtract	subtraction (-)		ck_null		IfsT2	S S
 i_subtract	integer subtraction (-)	ck_null		ifsT2	S S
-concat		concatenation (.) or string	ck_concat	fst2	S S
+concat		concatenation (.) or string	ck_concat	fsT2	S S
 stringify	string			ck_fun		fsT@	S
 
 left_shift	left bitshift (<<)	ck_bitop	fsT2	S S
-- 
2.7.4