[jogibear9988]

Lifted arithmetic can skip the right operand when the left is null, losing side effects and exceptions. Evaluate and cache the right operand first, then perform nullable checks. Reuse the existing nullable/value locals when consuming the cache.

Eight lifted arithmetic/bitwise operators; null and non-null combinations; exactly-once evaluation order and right-operand exceptions. Regressions use strict FEC compilation for both Standard and LightExpression.

Validation

Release solution build: zero warnings/errors.

Runtime	TestX groups	Legacy tests
.NET 10	445 passed	1,756 passed
.NET 8	445 passed	1,755 passed
.NET Framework 4.7.2	424 passed	1,639 passed

Measurements

Current master f1d2fb33 → this change, Release, Windows ARM64, .NET 8.0.28 / 10.0.9. Compilation uses prebuilt trees; runtime measures invocation through the same wrapper. Two fresh process rounds with reversed load order, seven samples per round, about 30 ms calibration, one logical CPU and tiered compilation disabled. Tables use the median of the two per-round medians.

The controls below produce correct results on master for their measured inputs. Newly supported trees have no valid before/after execution comparison because master rejects them, produces incorrect results or emits invalid IL. Timings include machine and JIT/code-placement variation; the unchanged add control helps show that variation. These observations do not prove universal performance neutrality.

net8.0 results (master → change)

API / workload	Compile ns	Invoke ns	Compile B/op	Invoke B/op
Standard / add_control	1412.8 → 1390.5	2.5 → 2.4	872.0 → 872.0	0.0 → 0.0
Standard / nullable_add	3729.5 → 3838.2	6.6 → 8.2	1928.0 → 1928.0	0.0 → 0.0
Standard / nullable_add_null	3589.1 → 3573.0	2.8 → 2.8	1928.0 → 1928.0	0.0 → 0.0
Light / add_control	1212.2 → 1325.9	2.3 → 2.4	872.0 → 872.0	0.0 → 0.0
Light / nullable_add	3400.6 → 2981.5	4.2 → 2.9	1928.0 → 1928.0	0.0 → 0.0
Light / nullable_add_null	2706.2 → 2750.2	2.4 → 2.5	1928.0 → 1928.0	0.0 → 0.0

net10.0 results (master → change)

API / workload	Compile ns	Invoke ns	Compile B/op	Invoke B/op
Standard / add_control	5485.8 → 5443.4	2.5 → 2.6	872.0 → 872.0	0.0 → 0.0
Standard / nullable_add	11979.1 → 13153.8	2.6 → 2.6	1928.0 → 1928.0	0.0 → 0.0
Standard / nullable_add_null	9784.4 → 9937.3	2.5 → 2.7	1928.0 → 1928.0	0.0 → 0.0
Light / add_control	2632.9 → 2529.8	2.0 → 2.0	872.0 → 872.0	0.0 → 0.0
Light / nullable_add	7643.5 → 8155.2	2.3 → 2.3	1928.0 → 1928.0	0.0 → 0.0
Light / nullable_add_null	8573.4 → 8029.7	2.8 → 3.0	1928.0 → 1928.0	0.0 → 0.0

Emitted IL differs in these measured workloads: nullable_add, nullable_add_null.
No measured allocation increase above 0.1 B/op in these controls.