gh-127022: Simplify `PyStackRef_FromPyObjectSteal` (#127024)

This gets rid of the immortal check in `PyStackRef_FromPyObjectSteal()`.
Overall, this improves performance about 2% in the free threading
build.

This also renames `PyStackRef_Is()` to `PyStackRef_IsExactly()` because
the macro requires that the tag bits of the arguments match, which is
only true in certain special cases.

1 files changed, 10 insertions, 18 deletions

diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index 22de7ca11cd..5af970ec4ae 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -445,7 +445,7 @@
             _PyStackRef res;
             value = stack_pointer[-1];
             assert(PyStackRef_BoolCheck(value));
-            res = PyStackRef_Is(value, PyStackRef_False)
+            res = PyStackRef_IsFalse(value)
             ? PyStackRef_True : PyStackRef_False;
             stack_pointer[-1] = res;
             break;
@@ -519,7 +519,7 @@
             _PyStackRef res;
             value = stack_pointer[-1];
             // This one is a bit weird, because we expect *some* failures:
-            if (!PyStackRef_Is(value, PyStackRef_None)) {
+            if (!PyStackRef_IsNone(value)) {
                 UOP_STAT_INC(uopcode, miss);
                 JUMP_TO_JUMP_TARGET();
             }
@@ -822,9 +822,7 @@
             _PyStackRef left;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            #ifndef NDEBUG
             PyObject *left_o = PyStackRef_AsPyObjectBorrow(left);
-            #endif
             PyObject *right_o = PyStackRef_AsPyObjectBorrow(right);
             int next_oparg;
             #if TIER_ONE
@@ -834,7 +832,7 @@
             next_oparg = CURRENT_OPERAND0();
             #endif
             _PyStackRef *target_local = &GETLOCAL(next_oparg);
-            if (!PyStackRef_Is(*target_local, left)) {
+            if (PyStackRef_AsPyObjectBorrow(*target_local) != left_o) {
                 UOP_STAT_INC(uopcode, miss);
                 JUMP_TO_JUMP_TARGET();
             }
@@ -1522,7 +1520,7 @@
             _PyErr_StackItem *exc_info = tstate->exc_info;
             _PyFrame_SetStackPointer(frame, stack_pointer);
             Py_XSETREF(exc_info->exc_value,
-                       PyStackRef_Is(exc_value, PyStackRef_None)
+                       PyStackRef_IsNone(exc_value)
                        ? NULL : PyStackRef_AsPyObjectSteal(exc_value));
             stack_pointer = _PyFrame_GetStackPointer(frame);
             stack_pointer += -1;
@@ -3110,13 +3108,7 @@
             oparg = CURRENT_OPARG();
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            #ifdef Py_GIL_DISABLED
-            // On free-threaded builds, objects are conditionally immortalized.
-            // So their bits don't always compare equally.
             int res = Py_Is(PyStackRef_AsPyObjectBorrow(left), PyStackRef_AsPyObjectBorrow(right)) ^ oparg;
-            #else
-            int res = PyStackRef_Is(left, right) ^ oparg;
-            #endif
             PyStackRef_CLOSE(left);
             PyStackRef_CLOSE(right);
             b = res ? PyStackRef_True : PyStackRef_False;
@@ -3320,7 +3312,7 @@
             _PyStackRef value;
             _PyStackRef b;
             value = stack_pointer[-1];
-            if (PyStackRef_Is(value, PyStackRef_None)) {
+            if (PyStackRef_IsNone(value)) {
                 b = PyStackRef_True;
             }
             else {
@@ -4562,7 +4554,7 @@
             _PyStackRef should_be_none;
             should_be_none = stack_pointer[-1];
             assert(STACK_LEVEL() == 2);
-            if (!PyStackRef_Is(should_be_none, PyStackRef_None)) {
+            if (!PyStackRef_IsNone(should_be_none)) {
                 _PyFrame_SetStackPointer(frame, stack_pointer);
                 PyErr_Format(PyExc_TypeError,
                              "__init__() should return None, not '%.200s'",
@@ -5643,7 +5635,7 @@
         case _GUARD_IS_TRUE_POP: {
             _PyStackRef flag;
             flag = stack_pointer[-1];
-            int is_true = PyStackRef_Is(flag, PyStackRef_True);
+            int is_true = PyStackRef_IsTrue(flag);
             stack_pointer += -1;
             assert(WITHIN_STACK_BOUNDS());
             if (!is_true) {
@@ -5656,7 +5648,7 @@
         case _GUARD_IS_FALSE_POP: {
             _PyStackRef flag;
             flag = stack_pointer[-1];
-            int is_false = PyStackRef_Is(flag, PyStackRef_False);
+            int is_false = PyStackRef_IsFalse(flag);
             stack_pointer += -1;
             assert(WITHIN_STACK_BOUNDS());
             if (!is_false) {
@@ -5669,7 +5661,7 @@
         case _GUARD_IS_NONE_POP: {
             _PyStackRef val;
             val = stack_pointer[-1];
-            int is_none = PyStackRef_Is(val, PyStackRef_None);
+            int is_none = PyStackRef_IsNone(val);
             if (!is_none) {
                 PyStackRef_CLOSE(val);
                 stack_pointer += -1;
@@ -5687,7 +5679,7 @@
         case _GUARD_IS_NOT_NONE_POP: {
             _PyStackRef val;
             val = stack_pointer[-1];
-            int is_none = PyStackRef_Is(val, PyStackRef_None);
+            int is_none = PyStackRef_IsNone(val);
             PyStackRef_CLOSE(val);
             stack_pointer += -1;
             assert(WITHIN_STACK_BOUNDS());