[mypyc] feat: extend get_expr_length to work with RTuple [2/4] (#19929)

This PR extends `get_expr_length` to work with type information from
RTuple types.

Author: BobTheBuidler

mypyc/irbuild/for_helpers.py

@@ -1203,18 +1203,18 @@ def gen_cleanup(self) -> None:
             gen.gen_cleanup()
 
 
-def get_expr_length(expr: Expression) -> int | None:
+def get_expr_length(builder: IRBuilder, expr: Expression) -> int | None:
     if isinstance(expr, (StrExpr, BytesExpr)):
         return len(expr.value)
     elif isinstance(expr, (ListExpr, TupleExpr)):
         # if there are no star expressions, or we know the length of them,
         # we know the length of the expression
-        stars = [get_expr_length(i) for i in expr.items if isinstance(i, StarExpr)]
+        stars = [get_expr_length(builder, i) for i in expr.items if isinstance(i, StarExpr)]
         if None not in stars:
             other = sum(not isinstance(i, StarExpr) for i in expr.items)
             return other + sum(stars)  # type: ignore [arg-type]
     elif isinstance(expr, StarExpr):
-        return get_expr_length(expr.expr)
+        return get_expr_length(builder, expr.expr)
     elif (
         isinstance(expr, RefExpr)
         and isinstance(expr.node, Var)
@@ -1227,6 +1227,11 @@ def get_expr_length(expr: Expression) -> int | None:
     # performance boost and can be (sometimes) figured out pretty easily. set and dict
     # comps *can* be done as well but will need special logic to consider the possibility
     # of key conflicts. Range, enumerate, zip are all simple logic.
+
+    # we might still be able to get the length directly from the type
+    rtype = builder.node_type(expr)
+    if isinstance(rtype, RTuple):
+        return len(rtype.types)
     return None
 
 
@@ -1235,7 +1240,7 @@ def get_expr_length_value(
 ) -> Value:
     rtype = builder.node_type(expr)
     assert is_sequence_rprimitive(rtype) or isinstance(rtype, RTuple), rtype
-    length = get_expr_length(expr)
+    length = get_expr_length(builder, expr)
     if length is None:
         # We cannot compute the length at compile time, so we will fetch it.
         return builder.builder.builtin_len(expr_reg, line, use_pyssize_t=use_pyssize_t)

mypyc/test-data/irbuild-tuple.test

@@ -694,51 +694,46 @@ L0:
     return r1
 def test():
     r0, source :: tuple[int, int, int]
-    r1 :: object
-    r2 :: native_int
-    r3 :: bit
-    r4, r5, r6 :: int
-    r7, r8, r9 :: object
-    r10, r11 :: tuple
-    r12 :: native_int
-    r13 :: bit
+    r1, r2, r3 :: int
+    r4, r5, r6 :: object
+    r7, r8 :: tuple
+    r9 :: native_int
+    r10 :: bit
+    r11 :: object
+    r12, x :: int
+    r13 :: bool
     r14 :: object
-    r15, x :: int
-    r16 :: bool
-    r17 :: object
-    r18 :: native_int
+    r15 :: native_int
     a :: tuple
 L0:
     r0 = (2, 4, 6)
     source = r0
-    r1 = box(tuple[int, int, int], source)
-    r2 = PyObject_Size(r1)
-    r3 = r2 >= 0 :: signed
-    r4 = source[0]
-    r5 = source[1]
-    r6 = source[2]
-    r7 = box(int, r4)
-    r8 = box(int, r5)
-    r9 = box(int, r6)
-    r10 = PyTuple_Pack(3, r7, r8, r9)
-    r11 = PyTuple_New(r2)
-    r12 = 0
+    r1 = source[0]
+    r2 = source[1]
+    r3 = source[2]
+    r4 = box(int, r1)
+    r5 = box(int, r2)
+    r6 = box(int, r3)
+    r7 = PyTuple_Pack(3, r4, r5, r6)
+    r8 = PyTuple_New(3)
+    r9 = 0
+    goto L2
 L1:
-    r13 = r12 < r2 :: signed
-    if r13 goto L2 else goto L4 :: bool
+    r10 = r9 < 3 :: signed
+    if r10 goto L2 else goto L4 :: bool
 L2:
-    r14 = CPySequenceTuple_GetItemUnsafe(r10, r12)
-    r15 = unbox(int, r14)
-    x = r15
-    r16 = f(x)
-    r17 = box(bool, r16)
-    CPySequenceTuple_SetItemUnsafe(r11, r12, r17)
+    r11 = CPySequenceTuple_GetItemUnsafe(r7, r9)
+    r12 = unbox(int, r11)
+    x = r12
+    r13 = f(x)
+    r14 = box(bool, r13)
+    CPySequenceTuple_SetItemUnsafe(r8, r9, r14)
 L3:
-    r18 = r12 + 1
-    r12 = r18
+    r15 = r9 + 1
+    r9 = r15
     goto L1
 L4:
-    a = r11
+    a = r8
     return 1
 
 [case testTupleBuiltFromFinalFixedLengthTuple]
@@ -762,19 +757,16 @@ L0:
 def test():
     r0 :: tuple[int, int, int]
     r1 :: bool
-    r2 :: object
-    r3 :: native_int
-    r4 :: bit
-    r5, r6, r7 :: int
-    r8, r9, r10 :: object
-    r11, r12 :: tuple
-    r13 :: native_int
-    r14 :: bit
+    r2, r3, r4 :: int
+    r5, r6, r7 :: object
+    r8, r9 :: tuple
+    r10 :: native_int
+    r11 :: bit
+    r12 :: object
+    r13, x :: int
+    r14 :: bool
     r15 :: object
-    r16, x :: int
-    r17 :: bool
-    r18 :: object
-    r19 :: native_int
+    r16 :: native_int
     a :: tuple
 L0:
     r0 = __main__.source :: static
@@ -783,34 +775,32 @@ L1:
     r1 = raise NameError('value for final name "source" was not set')
     unreachable
 L2:
-    r2 = box(tuple[int, int, int], r0)
-    r3 = PyObject_Size(r2)
-    r4 = r3 >= 0 :: signed
-    r5 = r0[0]
-    r6 = r0[1]
-    r7 = r0[2]
-    r8 = box(int, r5)
-    r9 = box(int, r6)
-    r10 = box(int, r7)
-    r11 = PyTuple_Pack(3, r8, r9, r10)
-    r12 = PyTuple_New(r3)
-    r13 = 0
+    r2 = r0[0]
+    r3 = r0[1]
+    r4 = r0[2]
+    r5 = box(int, r2)
+    r6 = box(int, r3)
+    r7 = box(int, r4)
+    r8 = PyTuple_Pack(3, r5, r6, r7)
+    r9 = PyTuple_New(3)
+    r10 = 0
+    goto L4
 L3:
-    r14 = r13 < r3 :: signed
-    if r14 goto L4 else goto L6 :: bool
+    r11 = r10 < 3 :: signed
+    if r11 goto L4 else goto L6 :: bool
 L4:
-    r15 = CPySequenceTuple_GetItemUnsafe(r11, r13)
-    r16 = unbox(int, r15)
-    x = r16
-    r17 = f(x)
-    r18 = box(bool, r17)
-    CPySequenceTuple_SetItemUnsafe(r12, r13, r18)
+    r12 = CPySequenceTuple_GetItemUnsafe(r8, r10)
+    r13 = unbox(int, r12)
+    x = r13
+    r14 = f(x)
+    r15 = box(bool, r14)
+    CPySequenceTuple_SetItemUnsafe(r9, r10, r15)
 L5:
-    r19 = r13 + 1
-    r13 = r19
+    r16 = r10 + 1
+    r10 = r16
     goto L3
 L6:
-    a = r12
+    a = r9
     return 1
 
 [case testTupleBuiltFromVariableLengthTuple]