8000 optimize for int=0 branching. move to correct branch · python/cpython@76793af · GitHub
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optimize for int=0 branching. move to correct branch
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‎Lib/test/test_capi/test_opt.py

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Original file line numberDiff line numberDiff line change
@@ -1437,6 +1437,67 @@ def crash_addition():
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crash_addition()
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def test_narrow_type_to_constant_int_zero(self):
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def f(n):
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trace = []
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for i in range(n):
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# f is always (int) 0, but we can only prove that it's a integer:
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f = i - i # at this point python knows f is an int, but doesnt know that it is 0 (we know it is 0 though)
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trace.append("A")
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if not f: # Kept.
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trace.append("B")
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if not f: # Removed!
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trace.append("C")
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trace.append("D")
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if f: # Removed!
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trace.append("X")
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trace.append("E")
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trace.append("F")
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if f: # Removed!
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trace.append("X")
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trace.append("G")
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return trace
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trace, ex = self._run_with_optimizer(f, TIER2_THRESHOLD)
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self.assertEqual(trace, list("ABCDEFG") * TIER2_THRESHOLD)
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self.assertIsNotNone(ex)
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uops = get_opnames(ex)
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# Only one guard remains:
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self.assertEqual(uops.count("_GUARD_IS_FALSE_POP"), 1)
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self.assertEqual(uops.count("_GUARD_IS_TRUE_POP"), 0)
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# But all of the appends we care about are still there:
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self.assertEqual(uops.count("_CALL_LIST_APPEND"), len("ABCDEFG"))
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# def test_narrow_type_to_constant_bool_true(self):
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# def f(n):
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# trace = []
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# for i in range(n):
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# # f is always True, but we can only prove that it's a bool:
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# f = i != TIER2_THRESHOLD
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# trace.append("A")
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# if f: # Kept.
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# trace.append("B")
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# if not f: # Removed!
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# trace.append("X")
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# trace.append("C")
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# if f: # Removed!
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# trace.append("D")
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# trace.append("E")
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# trace.append("F")
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# if not f: # Removed!
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# trace.append("X")
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# trace.append("G")
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# return trace
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# trace, ex = self._run_with_optimizer(f, TIER2_THRESHOLD)
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# self.assertEqual(trace, list("ABCDEFG") * TIER2_THRESHOLD)
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# self.assertIsNotNone(ex)
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# uops = get_opnames(ex)
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# # Only one guard remains:
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# self.assertEqual(uops.count("_GUARD_IS_FALSE_POP"), 0)
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# self.assertEqual(uops.count("_GUARD_IS_TRUE_POP"), 1)
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# # But all of the appends we care about are still there:
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# self.assertEqual(uops.count("_CALL_LIST_APPEND"), len("ABCDEFG"))
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def global_identity(x):
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return x

‎Python/optimizer_bytecodes.c

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Original file line numberDiff line numberDiff line change
@@ -407,6 +407,23 @@ dummy_func(void) {
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sym_set_type(value, &PyLong_Type);
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res = sym_new_type(ctx, &PyBool_Type);
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}
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if (!sym_is_const(value)) {
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assert(sym_matches_type(value, &PyLong_Type));
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int next_opcode = (this_instr + 1)->opcode;
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assert(next_opcode == _CHECK_VALIDITY_AND_SET_IP);
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next_opcode = (this_instr + 2)->opcode;
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// If the next uop is a guard, we can narrow value. However, we
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// *can't* narrow res, since that would cause the guard to be
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// removed and the narrowed value to be invalid:
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if (next_opcode == _GUARD_IS_FALSE_POP) {
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sym_set_const(value, Py_GetConstant(Py_CONSTANT_ZERO));
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res = sym_new_type(ctx, &PyLong_Type);
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}
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// else if (next_opcode == _GUARD_IS_TRUE_POP) {
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// sym_set_const(value, Py_True);
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// res = sym_new_type(ctx, &PyBool_Type);
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// }
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}
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}
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op(_TO_BOOL_LIST, (value -- res)) {

‎Python/optimizer_cases.c.h

Lines changed: 18 additions & 0 deletions
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