[davidwrighton]

Description

Extract the independent static-field intrinsic fix from #135553 onto main.

Recognize existing static-field intrinsics before selecting Wasm static-base helpers. Reads of IntPtr.Zero, UIntPtr.Zero, and BitConverter.IsLittleEndian can use constants, while String.Empty can use a string handle. Address-taking, writes, and ordinary static-field accesses retain their existing handling, including main's target-aware thread-static check.

Add a regression theory covering optimized/unoptimized and regular/composite compilation, with fixtures for both intrinsic reads and address-taking.

Source commit: 717befe76a5. This PR does not include two-phase compilation, direct calls, or the prolog/frame-identity changes.

Historical size and codegen measurements

These matched before/after measurements were collected on the original development branch, not on this newly extracted/rebased PR. The comparisons used identical input assemblies, profiles, compiler options, references, and JIT binaries. Brotli used quality 11 and window 22.

Wasm image	Raw before	Raw after	Raw savings	Brotli before	Brotli after	Brotli savings
Retail CoreLib	19,728,299	19,697,600	30,699	3,685,809	3,677,815	7,994
CoreLib + CallPerformance composite	13,481,936	13,454,067	27,869	2,941,278	2,935,335	5,943

Emitted method-body nodes shrank by 30,932 bytes in retail and 27,637 bytes in composite, with their counts unchanged. In the isolated intrinsic-read fixture, zero and endianness reads shrank from 47 to 17 Wasm body bytes and eliminated the static-base helper call; the empty-string read shrank from 47 to 24 bytes. Address-taking bodies were unchanged.

These are historical size/codegen results, not throughput benchmarks or a guarantee of equivalent savings on current main.

Validation

• git diff --check upstream/main...split/r2r-static-intrinsics — passed.
• Reviewed the extracted three-file diff for isolation and preservation of main's IsThreadStaticForTarget(field) handling.
• Builds, runtime tests, and new benchmarks for this extracted branch — not run, at the user's explicit request.

This remains a draft; build and runtime validation on the independent branch are outstanding.

Note

This PR was prepared with GitHub Copilot.

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