#define SvENDx(sv) ((PL_Sv = (sv)), SvEND(PL_Sv))
#ifdef DEBUGGING
-#define SvMAGIC(sv) ((assert(SvTYPE(sv) >= SVt_PVMG)), ((XPVMG*) SvANY(sv))->xmg_magic)
-#define SvSTASH(sv) ((assert(SvTYPE(sv) >= SVt_PVMG)), (XPVMG*) SvANY(sv))->xmg_stash
+#define SvMAGIC(sv) (*(assert(SvTYPE(sv) >= SVt_PVMG), &((XPVMG*) SvANY(sv))->xmg_magic))
+#define SvSTASH(sv) (*(assert(SvTYPE(sv) >= SVt_PVMG), &((XPVMG*) SvANY(sv))->xmg_stash))
#else
#define SvMAGIC(sv) ((XPVMG*) SvANY(sv))->xmg_magic
#define SvSTASH(sv) ((XPVMG*) SvANY(sv))->xmg_stash