Combine sv_utf8_upgrade with a following grow

1 files changed, 2 insertions, 1 deletions

diff --git a/sv.c b/sv.c
index 0d6939fe41..d944e2f6fc 100644
--- a/sv.c
+++ b/sv.c
@@ -4796,7 +4796,8 @@ Perl_sv_catsv_flags(pTHX_ SV *const dsv, register SV *const ssv, const I32 flags
 		    spv = SvPV_const(csv, slen);
 		}
 		else
-		    sv_utf8_upgrade_nomg(dsv);
+		    /* Leave enough space for the cat that's about to happen */
+		    sv_utf8_upgrade_flags_grow(dsv, 0, slen);
 	    }
 	    sv_catpvn_nomg(dsv, spv, slen);
 	}