regcomp.c: Use no_mg for 2nd fetch of pattern

The pattern could be tied, for example, and so only want to access it
once.  I couldn't come up with a test case that actually exercised this,
but I can think of future changes to regcomp that would.

[ this is a re-application by davem of commit
3e0b93e82af0f1a033bcdb918b413113f1d61cf0 ]

1 files changed, 3 insertions, 1 deletions

diff --git a/regcomp.c b/regcomp.c
index 14261a7481..6e60737179 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -5209,7 +5209,9 @@ Perl_re_op_compile(pTHX_ SV * const * const patternp, int pat_count,
 	    xend = exp + plen;
 	}
 	else {
-	    exp = (char*)Perl_bytes_to_utf8(aTHX_ (U8*)SvPV(pat, plen), &len);
+	    exp = (char*)Perl_bytes_to_utf8(aTHX_
+					    (U8*)SvPV_nomg(pat, plen),
+					    &len);
 	    xend = exp + len;
 	    SAVEFREEPV(exp);
 	}