[mypyc] Avoid boxing/unboxing when coercing between tuple types (#14899)

Instead, coerce each tuple item individually. This makes some coercions
between tuple types much faster, primarily because there is less (or no)
allocation and deallocation going on.

This speeds up the raytrace benchmark by about 7% (when using native
floats).

Related to mypyc/mypyc#99.

mypyc/irbuild/ll_builder.py

@@ -68,6 +68,7 @@
     SetMem,
     Truncate,
     TupleGet,
+    TupleSet,
     Unbox,
     Unreachable,
     Value,
@@ -354,11 +355,33 @@ def coerce(
                 return Float(float(src.value))
             elif is_tagged(src_type) and is_float_rprimitive(target_type):
                 return self.int_to_float(src, line)
-            else:
-                # To go from one unboxed type to another, we go through a boxed
-                # in-between value, for simplicity.
-                tmp = self.box(src)
-                return self.unbox_or_cast(tmp, target_type, line)
+            elif (
+                isinstance(src_type, RTuple)
+                and isinstance(target_type, RTuple)
+                and len(src_type.types) == len(target_type.types)
+            ):
+                # Coerce between two tuple types by coercing each item separately
+                values = []
+                for i in range(len(src_type.types)):
+                    v = None
+                    if isinstance(src, TupleSet):
+                        item = src.items[i]
+                        # We can't reuse register values, since they can be modified.
+                        if not isinstance(item, Register):
+                            v = item
+                    if v is None:
+                        v = TupleGet(src, i)
+                        self.add(v)
+                    values.append(v)
+                return self.add(
+                    TupleSet(
+                        [self.coerce(v, t, line) for v, t in zip(values, target_type.types)], line
+                    )
+                )
+            # To go between any other unboxed types, we go through a boxed
+            # in-between value, for simplicity.
+            tmp = self.box(src)
+            return self.unbox_or_cast(tmp, target_type, line)
         if (not src_type.is_unboxed and target_type.is_unboxed) or not is_subtype(
             src_type, target_type
         ):

mypyc/test-data/irbuild-float.test

@@ -475,3 +475,23 @@ def init(n: int) -> None:
     # narrowing assignments, generate errors here
     x: float = n  # E: Incompatible value representations in assignment (expression has type "int", variable has type "float")
     y: float = 5  # E: Incompatible value representations in assignment (expression has type "int", variable has type "float")
+
+[case testFloatCoerceTupleFromIntValues]
+from __future__ import annotations
+
+def f(x: int) -> None:
+    t: tuple[float, float, float] = (x, 2.5, -7)
+[out]
+def f(x):
+    x :: int
+    r0 :: tuple[int, float, int]
+    r1 :: int
+    r2 :: float
+    r3, t :: tuple[float, float, float]
+L0:
+    r0 = (x, 2.5, -14)
+    r1 = r0[0]
+    r2 = CPyFloat_FromTagged(r1)
+    r3 = (r2, 2.5, -7.0)
+    t = r3
+    return 1

mypyc/test-data/irbuild-i64.test

@@ -650,7 +650,6 @@ def f(x: i64, y: i64) -> Tuple[i64, i64]:
     return x, y
 
 def g() -> Tuple[i64, i64]:
-    # TODO: Avoid boxing and unboxing
     return 1, 2
 
 def h() -> i64:
@@ -666,13 +665,11 @@ L0:
     return r0
 def g():
     r0 :: tuple[int, int]
-    r1 :: object
-    r2 :: tuple[int64, int64]
+    r1 :: tuple[int64, int64]
 L0:
     r0 = (2, 4)
-    r1 = box(tuple[int, int], r0)
-    r2 = unbox(tuple[int64, int64], r1)
-    return r2
+    r1 = (1, 2)
+    return r1
 def h():
     r0 :: tuple[int64, int64]
     r1, x, r2, y :: int64
@@ -2081,3 +2078,78 @@ L2:
     r6 = r5.a
     keep_alive x
     return r6
+
+[case testI64ConvertBetweenTuples_64bit]
+from __future__ import annotations
+from mypy_extensions import i64
+
+def f(t: tuple[int, i64, int]) -> None:
+    tt: tuple[int, i64, i64] = t
+
+def g(n: int) -> None:
+    t: tuple[i64, i64] = (1, n)
+[out]
+def f(t):
+    t :: tuple[int, int64, int]
+    r0 :: int
+    r1 :: int64
+    r2 :: int
+    r3 :: native_int
+    r4 :: bit
+    r5, r6 :: int64
+    r7 :: ptr
+    r8 :: c_ptr
+    r9 :: int64
+    r10, tt :: tuple[int, int64, int64]
+L0:
+    r0 = t[0]
+    r1 = t[1]
+    r2 = t[2]
+    r3 = r2 & 1
+    r4 = r3 == 0
+    if r4 goto L1 else goto L2 :: bool
+L1:
+    r5 = r2 >> 1
+    r6 = r5
+    goto L3
+L2:
+    r7 = r2 ^ 1
+    r8 = r7
+    r9 = CPyLong_AsInt64(r8)
+    r6 = r9
+    keep_alive r2
+L3:
+    r10 = (r0, r1, r6)
+    tt = r10
+    return 1
+def g(n):
+    n :: int
+    r0 :: tuple[int, int]
+    r1 :: int
+    r2 :: native_int
+    r3 :: bit
+    r4, r5 :: int64
+    r6 :: ptr
+    r7 :: c_ptr
+    r8 :: int64
+    r9, t :: tuple[int64, int64]
+L0:
+    r0 = (2, n)
+    r1 = r0[1]
+    r2 = r1 & 1
+    r3 = r2 == 0
+    if r3 goto L1 else goto L2 :: bool
+L1:
+    r4 = r1 >> 1
+    r5 = r4
+    goto L3
+L2:
+    r6 = r1 ^ 1
+    r7 = r6
+    r8 = CPyLong_AsInt64(r7)
+    r5 = r8
+    keep_alive r1
+L3:
+    r9 = (1, r5)
+    t = r9
+    return 1

mypyc/test-data/run-floats.test

@@ -1,6 +1,7 @@
 # Test cases for floats (compile and run)
 
 [case testFloatOps]
+from __future__ import annotations
 from typing import Any, cast
 from typing_extensions import Final
 from testutil import assertRaises, float_vals, FLOAT_MAGIC
@@ -329,6 +330,13 @@ def test_undefined_local_var() -> None:
     with assertRaises(UnboundLocalError, 'local variable "y2" referenced before assignment'):
         print(y2)
 
+def test_tuples() -> None:
+    t1: tuple[float, float] = (1.5, 2.5)
+    assert t1 == tuple([1.5, 2.5])
+    n = int() + 5
+    t2: tuple[float, float, float, float] = (n, 1.5, -7, -113)
+    assert t2 == tuple([5.0, 1.5, -7.0, -113.0])
+
 [case testFloatGlueMethodsAndInheritance]
 from typing import Any
 from typing_extensions import Final