Eliminate PL_sawalias, GPf_ALIASED_SV

These two commits:

    v5.21.3-759-gff2a62e "Skip no-common-vars optimisation for aliases"
    v5.21.4-210-gc997e36 "Make list assignment respect foreach aliasing"

added a run-time mechanism to detect aliased package variables,
by either "*pkg = ...," or "for $pkg (...)", and used that information
to enable the OPpASSIGN_COMMON mechanism at runtime for detecting common
elements in a list assign, e.g.

    for $alias ($a, ...) {
        ($a,$b) = (1,$alias);
    }

The previous commit but one changed the OPpASSIGN_COMMON mechanism such
that it no longer uses PL_sawalias. So this var and the mechanism for
setting it can now be removed.

This commit removes:

    * the PL_sawalias variable
    * the GPf_ALIASED_SV GP flag
    * the SAVEt_GP_ALIASED_SV and save_aliased_sv() save type.

1 files changed, 0 insertions, 28 deletions

diff --git a/scope.c b/scope.c
index 5699d7cbd7..9768c30734 100644
--- a/scope.c
+++ b/scope.c
@@ -720,16 +720,6 @@ Perl_save_alloc(pTHX_ I32 size, I32 pad)
     return start;
 }
 
-void
-Perl_save_aliased_sv(pTHX_ GV *gv)
-{
-    dSS_ADD;
-    PERL_ARGS_ASSERT_SAVE_ALIASED_SV;
-    SS_ADD_PTR(gp_ref(GvGP(gv)));
-    SS_ADD_UV(SAVEt_GP_ALIASED_SV | cBOOL(GvALIASED_SV(gv)) << 8);
-    SS_ADD_END(2);
-}
-
 
 
 #define ARG0_SV  MUTABLE_SV(arg0.any_ptr)
@@ -1252,24 +1242,6 @@ Perl_leave_scope(pTHX_ I32 base)
 	case SAVEt_READONLY_OFF:
 	    SvREADONLY_off(ARG0_SV);
 	    break;
-	case SAVEt_GP_ALIASED_SV: {
-	    /* The GP may have been abandoned, leaving the savestack with
-	       the only remaining reference to it.  */
-	    GP * const gp = (GP *)ARG0_PTR;
-	    if (gp->gp_refcnt == 1) {
-		GV * const gv = (GV *)sv_2mortal(newSV_type(SVt_PVGV));
-		isGV_with_GP_on(gv);
-		GvGP_set(gv,gp);
-		gp_free(gv);
-		isGV_with_GP_off(gv);
-	    }
-	    else {
-		gp->gp_refcnt--;
-		if (uv >> 8) gp->gp_flags |=  GPf_ALIASED_SV;
-		else	     gp->gp_flags &= ~GPf_ALIASED_SV;
-	    }
-	    break;
-	}
 	default:
 	    Perl_croak(aTHX_ "panic: leave_scope inconsistency %u", type);
 	}