Eliminate AMGf_set flag

I added this flag a few years ago when I revamped the overload macros
tryAMAGICbin() etc. It allowed two different classes of macros to
share the same functions (Perl_try_amagic_un/Perl_try_amagic_bin)
by indicating what type of action is required.

However, the last few commits have made those two functions able to
robustly always determine whether its an assign-type action
($x op= $y or  $lex = $x op $x) or a plain set-result-on-stack operation
($x op $y).

So eliminate this flag.

Note that this makes the ops which have the AMGf_set flag hard-coded
infinitesimally slower, since Perl_try_amagic_bin no longer skips the
checks for assign-ness. But compared with the overhead of having
already called the overload method, this is is trivial.

On the plus side, it makes the code smaller and easier to understand.

4 files changed, 19 insertions, 30 deletions

diff --git a/gv.c b/gv.c
index 683a9f0cff..3beabe0838 100644
--- a/gv.c
+++ b/gv.c
@@ -2938,8 +2938,6 @@ Perl_gv_handler(pTHX_ HV *stash, I32 id)
 /* Implement tryAMAGICun_MG macro.
    Do get magic, then see if the stack arg is overloaded and if so call it.
    Flags:
-	AMGf_set     return the arg using SETs rather than assigning to
-		     the targ
 	AMGf_numeric apply sv_2num to the stack arg.
 */
 
@@ -2955,10 +2953,7 @@ Perl_try_amagic_un(pTHX_ int method, int flags) {
 					      AMGf_noright | AMGf_unary
 					    | (flags & AMGf_numarg))))
     {
-	if (flags & AMGf_set) {
-	    SETs(tmpsv);
-	}
-	else {
+	{
             /* where the op is of the form:
              *    $lex = $x op $y (where the assign is optimised away)
              * then assign the returned value to targ and return that;
@@ -2988,8 +2983,6 @@ Perl_try_amagic_un(pTHX_ int method, int flags) {
    Do get magic, then see if the two stack args are overloaded and if so
    call it.
    Flags:
-	AMGf_set     return the arg using SETs rather than assigning to
-		     the targ
 	AMGf_assign  op may be called as mutator (eg +=)
 	AMGf_numeric apply sv_2num to the stack arg.
 */
@@ -3013,11 +3006,7 @@ Perl_try_amagic_bin(pTHX_ int method, int flags) {
 		    (mutator ? AMGf_assign: 0)
 		  | (flags & AMGf_numarg));
 	if (tmpsv) {
-	    if (flags & AMGf_set) {
-		(void)POPs;
-		SETs(tmpsv);
-	    }
-	    else {
+	    {
 		(void)POPs;
                 /* where the op is one of the two forms:
                  *    $x op= $y
diff --git a/pp.c b/pp.c
index 522e985931..bf93ce76cd 100644
--- a/pp.c
+++ b/pp.c
@@ -2053,7 +2053,7 @@ PP(pp_lt)
     dSP;
     SV *left, *right;
 
-    tryAMAGICbin_MG(lt_amg, AMGf_set|AMGf_numeric);
+    tryAMAGICbin_MG(lt_amg, AMGf_numeric);
     right = POPs;
     left  = TOPs;
     SETs(boolSV(
@@ -2069,7 +2069,7 @@ PP(pp_gt)
     dSP;
     SV *left, *right;
 
-    tryAMAGICbin_MG(gt_amg, AMGf_set|AMGf_numeric);
+    tryAMAGICbin_MG(gt_amg, AMGf_numeric);
     right = POPs;
     left  = TOPs;
     SETs(boolSV(
@@ -2085,7 +2085,7 @@ PP(pp_le)
     dSP;
     SV *left, *right;
 
-    tryAMAGICbin_MG(le_amg, AMGf_set|AMGf_numeric);
+    tryAMAGICbin_MG(le_amg, AMGf_numeric);
     right = POPs;
     left  = TOPs;
     SETs(boolSV(
@@ -2101,7 +2101,7 @@ PP(pp_ge)
     dSP;
     SV *left, *right;
 
-    tryAMAGICbin_MG(ge_amg, AMGf_set|AMGf_numeric);
+    tryAMAGICbin_MG(ge_amg, AMGf_numeric);
     right = POPs;
     left  = TOPs;
     SETs(boolSV(
@@ -2117,7 +2117,7 @@ PP(pp_ne)
     dSP;
     SV *left, *right;
 
-    tryAMAGICbin_MG(ne_amg, AMGf_set|AMGf_numeric);
+    tryAMAGICbin_MG(ne_amg, AMGf_numeric);
     right = POPs;
     left  = TOPs;
     SETs(boolSV(
@@ -2249,7 +2249,7 @@ PP(pp_sle)
 	break;
     }
 
-    tryAMAGICbin_MG(amg_type, AMGf_set);
+    tryAMAGICbin_MG(amg_type, 0);
     {
       dPOPTOPssrl;
       const int cmp =
@@ -2267,7 +2267,7 @@ PP(pp_sle)
 PP(pp_seq)
 {
     dSP;
-    tryAMAGICbin_MG(seq_amg, AMGf_set);
+    tryAMAGICbin_MG(seq_amg, 0);
     {
       dPOPTOPssrl;
       SETs(boolSV(sv_eq_flags(left, right, 0)));
@@ -2278,7 +2278,7 @@ PP(pp_seq)
 PP(pp_sne)
 {
     dSP;
-    tryAMAGICbin_MG(sne_amg, AMGf_set);
+    tryAMAGICbin_MG(sne_amg, 0);
     {
       dPOPTOPssrl;
       SETs(boolSV(!sv_eq_flags(left, right, 0)));
@@ -2513,7 +2513,7 @@ PP(pp_not)
     dSP;
     SV *sv;
 
-    tryAMAGICun_MG(not_amg, AMGf_set);
+    tryAMAGICun_MG(not_amg, 0);
     sv = *PL_stack_sp;
     *PL_stack_sp = boolSV(!SvTRUE_nomg_NN(sv));
     return NORMAL;
@@ -2710,7 +2710,7 @@ PP(pp_i_subtract)
 PP(pp_i_lt)
 {
     dSP;
-    tryAMAGICbin_MG(lt_amg, AMGf_set);
+    tryAMAGICbin_MG(lt_amg, 0);
     {
       dPOPTOPiirl_nomg;
       SETs(boolSV(left < right));
@@ -2721,7 +2721,7 @@ PP(pp_i_lt)
 PP(pp_i_gt)
 {
     dSP;
-    tryAMAGICbin_MG(gt_amg, AMGf_set);
+    tryAMAGICbin_MG(gt_amg, 0);
     {
       dPOPTOPiirl_nomg;
       SETs(boolSV(left > right));
@@ -2732,7 +2732,7 @@ PP(pp_i_gt)
 PP(pp_i_le)
 {
     dSP;
-    tryAMAGICbin_MG(le_amg, AMGf_set);
+    tryAMAGICbin_MG(le_amg, 0);
     {
       dPOPTOPiirl_nomg;
       SETs(boolSV(left <= right));
@@ -2743,7 +2743,7 @@ PP(pp_i_le)
 PP(pp_i_ge)
 {
     dSP;
-    tryAMAGICbin_MG(ge_amg, AMGf_set);
+    tryAMAGICbin_MG(ge_amg, 0);
     {
       dPOPTOPiirl_nomg;
       SETs(boolSV(left >= right));
@@ -2754,7 +2754,7 @@ PP(pp_i_ge)
 PP(pp_i_eq)
 {
     dSP;
-    tryAMAGICbin_MG(eq_amg, AMGf_set);
+    tryAMAGICbin_MG(eq_amg, 0);
     {
       dPOPTOPiirl_nomg;
       SETs(boolSV(left == right));
@@ -2765,7 +2765,7 @@ PP(pp_i_eq)
 PP(pp_i_ne)
 {
     dSP;
-    tryAMAGICbin_MG(ne_amg, AMGf_set);
+    tryAMAGICbin_MG(ne_amg, 0);
     {
       dPOPTOPiirl_nomg;
       SETs(boolSV(left != right));
diff --git a/pp.h b/pp.h
index 61e26c5dc8..98540be682 100644
--- a/pp.h
+++ b/pp.h
@@ -556,7 +556,7 @@ Does not use C<TARG>.  See also C<L</XPUSHu>>, C<L</mPUSHu>> and C<L</PUSHu>>.
 #define AMGf_assign	4       /* op supports mutator variant, e.g. $x += 1 */
 #define AMGf_unary	8
 #define AMGf_numeric	0x10	/* for Perl_try_amagic_bin */
-#define AMGf_set	0x20	/* for Perl_try_amagic_bin */
+
 #define AMGf_want_list	0x40
 #define AMGf_numarg	0x80
 
diff --git a/pp_hot.c b/pp_hot.c
index 39aef72f7c..fd439a5e4b 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -1257,7 +1257,7 @@ PP(pp_eq)
     dSP;
     SV *left, *right;
 
-    tryAMAGICbin_MG(eq_amg, AMGf_set|AMGf_numeric);
+    tryAMAGICbin_MG(eq_amg, AMGf_numeric);
     right = POPs;
     left  = TOPs;
     SETs(boolSV(