Remove conditional stack effects -- We no longer need them

Author: markshannon

Python/bytecodes.c

@@ -59,7 +59,6 @@
 #define guard
 #define override
 #define specializing
-#define split
 #define replicate(TIMES)
 #define tier1
 #define no_save_ip
@@ -1686,8 +1685,10 @@ dummy_func(
             ERROR_IF(PyStackRef_IsNull(*res), error);
         }
 
-        op(_PUSH_NULL_CONDITIONAL, ( -- null if (oparg & 1))) {
-            null = PyStackRef_NULL;
+        op(_PUSH_NULL_CONDITIONAL, ( -- null[oparg & 1])) {
+            if (oparg & 1) {
+                null[0] = PyStackRef_NULL;
+            }
         }
 
         macro(LOAD_GLOBAL) =

Python/executor_cases.c.h

@@ -1226,11 +1226,7 @@ uop_optimize(
     for (int pc = 0; pc < length; pc++) {
         int opcode = buffer[pc].opcode;
         int oparg = buffer[pc].oparg;
-        if (_PyUop_Flags[opcode] & HAS_OPARG_AND_1_FLAG) {
-            buffer[pc].opcode = opcode + 1 + (oparg & 1);
-            assert(strncmp(_PyOpcode_uop_name[buffer[pc].opcode], _PyOpcode_uop_name[opcode], strlen(_PyOpcode_uop_name[opcode])) == 0);
-        }
-        else if (oparg < _PyUop_Replication[opcode]) {
+        if (oparg < _PyUop_Replication[opcode]) {
             buffer[pc].opcode = opcode + oparg + 1;
             assert(strncmp(_PyOpcode_uop_name[buffer[pc].opcode], _PyOpcode_uop_name[opcode], strlen(_PyOpcode_uop_name[opcode])) == 0);
         }

Python/generated_cases.c.h

@@ -546,10 +546,14 @@ dummy_func(void) {
         }
     }
 
-    op (_PUSH_NULL_CONDITIONAL, ( -- null if (oparg & 1))) {
-        int opcode = (oparg & 1) ? _PUSH_NULL : _NOP;
-        REPLACE_OP(this_instr, opcode, 0, 0);
-        null = sym_new_null(ctx);
+    op (_PUSH_NULL_CONDITIONAL, ( -- null[oparg & 1])) {
+        if (oparg & 1) {
+            REPLACE_OP(this_instr, _PUSH_NULL, 0, 0);
+            null[0] = sym_new_null(ctx);
+        }
+        else {
+            REPLACE_OP(this_instr, _NOP);
+        }
     }
 
     op(_LOAD_ATTR, (owner -- attr, self_or_null[oparg&1])) {
@@ -765,7 +769,7 @@ dummy_func(void) {
         Py_UNREACHABLE();
     }
 
-    op(_PUSH_FRAME, (new_frame: _Py_UOpsAbstractFrame * -- unused if (0))) {
+    op(_PUSH_FRAME, (new_frame: _Py_UOpsAbstractFrame * -- )) {
         SYNC_SP();
         ctx->frame->stack_pointer = stack_pointer;
         ctx->frame = new_frame;