gh-115859: Re-enable T2 optimizer pass by default (#116062)

This undoes the *temporary* default disabling of the T2 optimizer pass in gh-115860.

- Add a new test that reproduces Brandt's example from gh-115859; it indeed crashes before gh-116028 with PYTHONUOPSOPTIMIZE=1
- Re-enable the optimizer pass in T2, stop checking PYTHONUOPSOPTIMIZE
- Rename the env var to disable T2 entirely to PYTHON_UOPS_OPTIMIZE (must be explicitly set to 0 to disable)
- Fix skipIf conditions on tests in test_opt.py accordingly
- Export sym_is_bottom() (for debugging)
- Fix various things in the `_BINARY_OP_` specializations in the abstract interpreter:
  - DECREF(temp)
  - out-of-space check after sym_new_const()
  - add sym_matches_type() checks, so even if we somehow reach a binary op with symbolic constants of the wrong type on the stack we won't trigger the type assert

5 files changed, 74 insertions, 27 deletions

diff --git a/Python/optimizer.c b/Python/optimizer.c
index c04ee17..acd6d52 100644
--- a/Python/optimizer.c
+++ b/Python/optimizer.c
@@ -1008,8 +1008,8 @@ uop_optimize(
         return err;
     }
     OPT_STAT_INC(traces_created);
-    char *uop_optimize = Py_GETENV("PYTHONUOPSOPTIMIZE");
-    if (uop_optimize == NULL || *uop_optimize > '0') {
+    char *env_var = Py_GETENV("PYTHON_UOPS_OPTIMIZE");
+    if (env_var == NULL || *env_var == '\0' || *env_var > '0') {
         err = _Py_uop_analyze_and_optimize(frame, buffer,
                                            UOP_MAX_TRACE_LENGTH,
                                            curr_stackentries, &dependencies);
diff --git a/Python/optimizer_analysis.c b/Python/optimizer_analysis.c
index 8e408ff..2a7ef4e 100644
--- a/Python/optimizer_analysis.c
+++ b/Python/optimizer_analysis.c
@@ -297,6 +297,7 @@ remove_globals(_PyInterpreterFrame *frame, _PyUOpInstruction *buffer,
 #define sym_set_non_null _Py_uop_sym_set_non_null
 #define sym_set_type _Py_uop_sym_set_type
 #define sym_set_const _Py_uop_sym_set_const
+#define sym_is_bottom _Py_uop_sym_is_bottom
 #define frame_new _Py_uop_frame_new
 #define frame_pop _Py_uop_frame_pop
 
@@ -510,12 +511,9 @@ _Py_uop_analyze_and_optimize(
 
     peephole_opt(frame, buffer, buffer_size);
 
-    char *uop_optimize = Py_GETENV("PYTHONUOPSOPTIMIZE");
-    if (uop_optimize != NULL && *uop_optimize > '0') {
-        err = optimize_uops(
-            (PyCodeObject *)frame->f_executable, buffer,
-            buffer_size, curr_stacklen, dependencies);
-    }
+    err = optimize_uops(
+        (PyCodeObject *)frame->f_executable, buffer,
+        buffer_size, curr_stacklen, dependencies);
 
     if (err == 0) {
         goto not_ready;
diff --git a/Python/optimizer_bytecodes.c b/Python/optimizer_bytecodes.c
index b65e90b..928c22d 100644
--- a/Python/optimizer_bytecodes.c
+++ b/Python/optimizer_bytecodes.c
@@ -25,6 +25,7 @@ typedef struct _Py_UOpsAbstractFrame _Py_UOpsAbstractFrame;
 #define sym_set_non_null _Py_uop_sym_set_non_null
 #define sym_set_type _Py_uop_sym_set_type
 #define sym_set_const _Py_uop_sym_set_const
+#define sym_is_bottom _Py_uop_sym_is_bottom
 #define frame_new _Py_uop_frame_new
 #define frame_pop _Py_uop_frame_pop
 
@@ -107,7 +108,9 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_ADD_INT, (left, right -- res)) {
-        if (sym_is_const(left) && sym_is_const(right)) {
+        if (sym_is_const(left) && sym_is_const(right) &&
+            sym_matches_type(left, &PyLong_Type) && sym_matches_type(right, &PyLong_Type))
+        {
             assert(PyLong_CheckExact(sym_get_const(left)));
             assert(PyLong_CheckExact(sym_get_const(right)));
             PyObject *temp = _PyLong_Add((PyLongObject *)sym_get_const(left),
@@ -115,7 +118,9 @@ dummy_func(void) {
             if (temp == NULL) {
                 goto error;
             }
-            OUT_OF_SPACE_IF_NULL(res = sym_new_const(ctx, temp));
+            res = sym_new_const(ctx, temp);
+            Py_DECREF(temp);
+            OUT_OF_SPACE_IF_NULL(res);
             // TODO gh-115506:
             // replace opcode with constant propagated one and add tests!
         }
@@ -125,7 +130,9 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_SUBTRACT_INT, (left, right -- res)) {
-        if (sym_is_const(left) && sym_is_const(right)) {
+        if (sym_is_const(left) && sym_is_const(right) &&
+            sym_matches_type(left, &PyLong_Type) && sym_matches_type(right, &PyLong_Type))
+        {
             assert(PyLong_CheckExact(sym_get_const(left)));
             assert(PyLong_CheckExact(sym_get_const(right)));
             PyObject *temp = _PyLong_Subtract((PyLongObject *)sym_get_const(left),
@@ -133,7 +140,9 @@ dummy_func(void) {
             if (temp == NULL) {
                 goto error;
             }
-            OUT_OF_SPACE_IF_NULL(res = sym_new_const(ctx, temp));
+            res = sym_new_const(ctx, temp);
+            Py_DECREF(temp);
+            OUT_OF_SPACE_IF_NULL(res);
             // TODO gh-115506:
             // replace opcode with constant propagated one and add tests!
         }
@@ -143,7 +152,9 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_MULTIPLY_INT, (left, right -- res)) {
-        if (sym_is_const(left) && sym_is_const(right)) {
+        if (sym_is_const(left) && sym_is_const(right) &&
+            sym_matches_type(left, &PyLong_Type) && sym_matches_type(right, &PyLong_Type))
+        {
             assert(PyLong_CheckExact(sym_get_const(left)));
             assert(PyLong_CheckExact(sym_get_const(right)));
             PyObject *temp = _PyLong_Multiply((PyLongObject *)sym_get_const(left),
@@ -151,7 +162,9 @@ dummy_func(void) {
             if (temp == NULL) {
                 goto error;
             }
-            OUT_OF_SPACE_IF_NULL(res = sym_new_const(ctx, temp));
+            res = sym_new_const(ctx, temp);
+            Py_DECREF(temp);
+            OUT_OF_SPACE_IF_NULL(res);
             // TODO gh-115506:
             // replace opcode with constant propagated one and add tests!
         }
@@ -161,7 +174,9 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_ADD_FLOAT, (left, right -- res)) {
-        if (sym_is_const(left) && sym_is_const(right)) {
+        if (sym_is_const(left) && sym_is_const(right) &&
+            sym_matches_type(left, &PyFloat_Type) && sym_matches_type(right, &PyFloat_Type))
+        {
             assert(PyFloat_CheckExact(sym_get_const(left)));
             assert(PyFloat_CheckExact(sym_get_const(right)));
             PyObject *temp = PyFloat_FromDouble(
@@ -171,6 +186,8 @@ dummy_func(void) {
                 goto error;
             }
             res = sym_new_const(ctx, temp);
+            Py_DECREF(temp);
+            OUT_OF_SPACE_IF_NULL(res);
             // TODO gh-115506:
             // replace opcode with constant propagated one and update tests!
         }
@@ -180,7 +197,9 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_SUBTRACT_FLOAT, (left, right -- res)) {
-        if (sym_is_const(left) && sym_is_const(right)) {
+        if (sym_is_const(left) && sym_is_const(right) &&
+            sym_matches_type(left, &PyFloat_Type) && sym_matches_type(right, &PyFloat_Type))
+        {
             assert(PyFloat_CheckExact(sym_get_const(left)));
             assert(PyFloat_CheckExact(sym_get_const(right)));
             PyObject *temp = PyFloat_FromDouble(
@@ -190,6 +209,8 @@ dummy_func(void) {
                 goto error;
             }
             res = sym_new_const(ctx, temp);
+            Py_DECREF(temp);
+            OUT_OF_SPACE_IF_NULL(res);
             // TODO gh-115506:
             // replace opcode with constant propagated one and update tests!
         }
@@ -199,7 +220,9 @@ dummy_func(void) {
     }
 
     op(_BINARY_OP_MULTIPLY_FLOAT, (left, right -- res)) {
-        if (sym_is_const(left) && sym_is_const(right)) {
+        if (sym_is_const(left) && sym_is_const(right) &&
+            sym_matches_type(left, &PyFloat_Type) && sym_matches_type(right, &PyFloat_Type))
+        {
             assert(PyFloat_CheckExact(sym_get_const(left)));
             assert(PyFloat_CheckExact(sym_get_const(right)));
             PyObject *temp = PyFloat_FromDouble(
@@ -209,6 +232,8 @@ dummy_func(void) {
                 goto error;
             }
             res = sym_new_const(ctx, temp);
+            Py_DECREF(temp);
+            OUT_OF_SPACE_IF_NULL(res);
             // TODO gh-115506:
             // replace opcode with constant propagated one and update tests!
         }
diff --git a/Python/optimizer_cases.c.h b/Python/optimizer_cases.c.h
index 9e99c83..9b387c0 100644
--- a/Python/optimizer_cases.c.h
+++ b/Python/optimizer_cases.c.h
@@ -183,7 +183,9 @@
             _Py_UopsSymbol *res;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            if (sym_is_const(left) && sym_is_const(right)) {
+            if (sym_is_const(left) && sym_is_const(right) &&
+                sym_matches_type(left, &PyLong_Type) && sym_matches_type(right, &PyLong_Type))
+            {
                 assert(PyLong_CheckExact(sym_get_const(left)));
                 assert(PyLong_CheckExact(sym_get_const(right)));
                 PyObject *temp = _PyLong_Multiply((PyLongObject *)sym_get_const(left),
@@ -191,7 +193,9 @@
                 if (temp == NULL) {
                     goto error;
                 }
-                OUT_OF_SPACE_IF_NULL(res = sym_new_const(ctx, temp));
+                res = sym_new_const(ctx, temp);
+                Py_DECREF(temp);
+                OUT_OF_SPACE_IF_NULL(res);
                 // TODO gh-115506:
                 // replace opcode with constant propagated one and add tests!
             }
@@ -209,7 +213,9 @@
             _Py_UopsSymbol *res;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            if (sym_is_const(left) && sym_is_const(right)) {
+            if (sym_is_const(left) && sym_is_const(right) &&
+                sym_matches_type(left, &PyLong_Type) && sym_matches_type(right, &PyLong_Type))
+            {
                 assert(PyLong_CheckExact(sym_get_const(left)));
                 assert(PyLong_CheckExact(sym_get_const(right)));
                 PyObject *temp = _PyLong_Add((PyLongObject *)sym_get_const(left),
@@ -217,7 +223,9 @@
                 if (temp == NULL) {
                     goto error;
                 }
-                OUT_OF_SPACE_IF_NULL(res = sym_new_const(ctx, temp));
+                res = sym_new_const(ctx, temp);
+                Py_DECREF(temp);
+                OUT_OF_SPACE_IF_NULL(res);
                 // TODO gh-115506:
                 // replace opcode with constant propagated one and add tests!
             }
@@ -235,7 +243,9 @@
             _Py_UopsSymbol *res;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            if (sym_is_const(left) && sym_is_const(right)) {
+            if (sym_is_const(left) && sym_is_const(right) &&
+                sym_matches_type(left, &PyLong_Type) && sym_matches_type(right, &PyLong_Type))
+            {
                 assert(PyLong_CheckExact(sym_get_const(left)));
                 assert(PyLong_CheckExact(sym_get_const(right)));
                 PyObject *temp = _PyLong_Subtract((PyLongObject *)sym_get_const(left),
@@ -243,7 +253,9 @@
                 if (temp == NULL) {
                     goto error;
                 }
-                OUT_OF_SPACE_IF_NULL(res = sym_new_const(ctx, temp));
+                res = sym_new_const(ctx, temp);
+                Py_DECREF(temp);
+                OUT_OF_SPACE_IF_NULL(res);
                 // TODO gh-115506:
                 // replace opcode with constant propagated one and add tests!
             }
@@ -275,7 +287,9 @@
             _Py_UopsSymbol *res;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            if (sym_is_const(left) && sym_is_const(right)) {
+            if (sym_is_const(left) && sym_is_const(right) &&
+                sym_matches_type(left, &PyFloat_Type) && sym_matches_type(right, &PyFloat_Type))
+            {
                 assert(PyFloat_CheckExact(sym_get_const(left)));
                 assert(PyFloat_CheckExact(sym_get_const(right)));
                 PyObject *temp = PyFloat_FromDouble(
@@ -285,6 +299,8 @@
                     goto error;
                 }
                 res = sym_new_const(ctx, temp);
+                Py_DECREF(temp);
+                OUT_OF_SPACE_IF_NULL(res);
                 // TODO gh-115506:
                 // replace opcode with constant propagated one and update tests!
             }
@@ -302,7 +318,9 @@
             _Py_UopsSymbol *res;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            if (sym_is_const(left) && sym_is_const(right)) {
+            if (sym_is_const(left) && sym_is_const(right) &&
+                sym_matches_type(left, &PyFloat_Type) && sym_matches_type(right, &PyFloat_Type))
+            {
                 assert(PyFloat_CheckExact(sym_get_const(left)));
                 assert(PyFloat_CheckExact(sym_get_const(right)));
                 PyObject *temp = PyFloat_FromDouble(
@@ -312,6 +330,8 @@
                     goto error;
                 }
                 res = sym_new_const(ctx, temp);
+                Py_DECREF(temp);
+                OUT_OF_SPACE_IF_NULL(res);
                 // TODO gh-115506:
                 // replace opcode with constant propagated one and update tests!
             }
@@ -329,7 +349,9 @@
             _Py_UopsSymbol *res;
             right = stack_pointer[-1];
             left = stack_pointer[-2];
-            if (sym_is_const(left) && sym_is_const(right)) {
+            if (sym_is_const(left) && sym_is_const(right) &&
+                sym_matches_type(left, &PyFloat_Type) && sym_matches_type(right, &PyFloat_Type))
+            {
                 assert(PyFloat_CheckExact(sym_get_const(left)));
                 assert(PyFloat_CheckExact(sym_get_const(right)));
                 PyObject *temp = PyFloat_FromDouble(
@@ -339,6 +361,8 @@
                     goto error;
                 }
                 res = sym_new_const(ctx, temp);
+                Py_DECREF(temp);
+                OUT_OF_SPACE_IF_NULL(res);
                 // TODO gh-115506:
                 // replace opcode with constant propagated one and update tests!
             }
diff --git a/Python/optimizer_symbols.c b/Python/optimizer_symbols.c
index 158ee67..a529cc2 100644
--- a/Python/optimizer_symbols.c
+++ b/Python/optimizer_symbols.c
@@ -77,7 +77,7 @@ sym_set_bottom(_Py_UopsSymbol *sym)
     Py_CLEAR(sym->const_val);
 }
 
-static inline bool
+bool
 _Py_uop_sym_is_bottom(_Py_UopsSymbol *sym)
 {
     if ((sym->flags & IS_NULL) && (sym->flags & NOT_NULL)) {