Don't optimize during quickening

Author: mpage

Python/specialize.c

@@ -447,25 +447,6 @@ do { \
 #  define SPECIALIZATION_FAIL(opcode, kind) ((void)0)
 #endif
 
-#define NUM_VARS 256
-
-static inline void
-set_mutated(bool *mutated, int i)
-{
-    if (i < NUM_VARS) {
-        mutated[i] = true;
-    }
-}
-
-static inline bool
-get_mutated(bool *mutated, int i)
-{
-    if (i > NUM_VARS) {
-        return true;
-    }
-    return mutated[i];
-}
-
 // Initialize warmup counters and optimize instructions. This cannot fail.
 void
 _PyCode_Quicken(_Py_CODEUNIT *instructions, Py_ssize_t size, int enable_counters)
@@ -482,32 +463,11 @@ _PyCode_Quicken(_Py_CODEUNIT *instructions, Py_ssize_t size, int enable_counters
     }
     int opcode = 0;
     int oparg = 0;
-    bool mutated[NUM_VARS];
-    for (int i = 0; i < NUM_VARS; i++) {
-        mutated[i] = false;
-    }
     /* The last code unit cannot have a cache, so we don't need to check it */
-    for (Py_ssize_t i = 0; i < size; i++) {
+    for (Py_ssize_t i = 0; i < size-1; i++) {
         opcode = instructions[i].op.code;
         int caches = _PyOpcode_Caches[opcode];
         oparg = (oparg << 8) | instructions[i].op.arg;
-        switch (opcode) {
-            case LOAD_FAST_AND_CLEAR:
-            case DELETE_FAST:
-            case MAKE_CELL:
-            case STORE_FAST:
-                set_mutated(mutated, oparg);
-                break;
-            case STORE_FAST_STORE_FAST:
-                set_mutated(mutated, oparg >> 4);
-                set_mutated(mutated, oparg & 15);
-                break;
-            case STORE_FAST_LOAD_FAST:
-                set_mutated(mutated, oparg >> 4);
-                break;
-            default:
-                break;
-        }
         if (caches) {
             // The initial value depends on the opcode
             switch (opcode) {
@@ -530,34 +490,6 @@ _PyCode_Quicken(_Py_CODEUNIT *instructions, Py_ssize_t size, int enable_counters
             oparg = 0;
         }
     }
-
-    /* The last code unit cannot have a cache, so we don't need to check it */
-    opcode = 0;
-    oparg = 0;
-    int eligible = 0;
-    int total = 0;
-    for (Py_ssize_t i = 0; i < size; i++) {
-        opcode = instructions[i].op.code;
-        oparg = (oparg << 8) | instructions[i].op.arg;
-        if (opcode == LOAD_FAST) {
-            total++;
-            if (!get_mutated(mutated, oparg)) {
-                instructions[i].op.code = LOAD_FAST_BORROW;
-                eligible++;
-            }
-        }
-        else if (opcode == LOAD_FAST_LOAD_FAST) {
-            total++;
-            if (!get_mutated(mutated, oparg >> 4) && !get_mutated(mutated, oparg & 15)) {
-                instructions[i].op.code = LOAD_FAST_BORROW_LOAD_FAST_BORROW;
-                eligible++;
-            }
-        }
-        if (opcode != EXTENDED_ARG) {
-            oparg = 0;
-        }
-    }
-    // fprintf(stderr, "== LF_SPEC %d %d\n", eligible, total);
     #endif /* ENABLE_SPECIALIZATION_FT */
 }