[Wasm RyuJIT] Address block store issues from #125756

[kg]

Fixes some of the issues from #125756 , at least based on my isolated repros.

cc @AndyAyersMS still figuring this out, don't completely understand it.

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[Copilot]

Pull request overview

This PR targets WebAssembly RyuJIT block-store lowering/codegen issues that are triggering asserts during crossgen/debug builds (per #125756), by adjusting how GT_STORE_BLK operands are represented/contained for memory.copy/memory.fill.

Changes:

• Update WASM LowerBlockStore to treat GT_IND sources as contained, and attempt to convert local sources to addresses for the memory.copy opcode path.
• Add debug assertions in WASM codegen to validate containment expectations for native bulk-memory op emission (memory.copy / memory.fill).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/coreclr/jit/lowerwasm.cpp	Changes block-store source handling/containment and attempts to convert local sources into address form for memory.copy.
src/coreclr/jit/codegenwasm.cpp	Adds debug assertions around contained operands for the native bulk-memory opcode path.

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[AndyAyersMS]

This looks good to me overall.

[Copilot]

Pull request overview

This PR targets WASM RyuJIT block-store correctness by adjusting lowering/RA hints and consolidating codegen paths for different GT_STORE_BLK lowering kinds, aiming to address debug/assert failures reported in #125756.

Changes:

• Move SetMultiplyUsed marking in LowerBlockStore so it applies consistently across block-store kinds.
• Route BlkOpKindNativeOpcode block stores through genCodeForCpObj to share logic with the CpObjUnroll path.
• Refactor genCodeForCpObj operand handling to support both cpobj and native memory.copy/memory.fill.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
src/coreclr/jit/lowerwasm.cpp	Moves multiply-used marking to apply across cpobj and native-op block stores.
src/coreclr/jit/codegenwasm.cpp	Unifies NativeOpcode handling with CpObjUnroll and refactors operand decoding/emission.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 5 comments.

[kg]

Rewrote most of the codegen changes from scratch so I'm resolving all the old comments.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

[kg]

Null checks are missing because they unbalance the stack:

node:internal/modules/run_main:107
    triggerUncaughtException(
    ^

[CompileError: WebAssembly.compile(): Compiling function #7 failed: not enough arguments on the stack for memory.fill (need 3, got 2) @+1809]

Node.js v25.2.1

Not sure what's going on there.

[kg]

I still need to do the optimization in lowering that singleaccretion suggested, but I think this is done otherwise now after the rewrite...

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

[Copilot]

genCodeForStoreBlk now calls genConsumeReg(dest) / genConsumeReg(src) up front. For contained operands (e.g., src is often a contained GT_IND for copyblk), this bypasses genConsumeRegs recursion and fails to consume the actual address operand (and doesn't follow the required execution-order consumption pattern used elsewhere, e.g. genCodeForStoreInd). This can leave operand liveness/GC tracking inconsistent and can break the Wasm evaluation stack invariants for block ops.

Consider switching back to genConsumeOperands(blkOp) (or explicitly genConsumeAddress(dest) + genConsumeRegs(src) with the same contained-node handling as genConsumeRegs), and only call genConsumeReg on the specific non-contained nodes you truly consume (e.g., the unwrapped GT_IND address node).

Suggested change

	regNumber destReg = genConsumeReg(dest);
	regNumber srcReg = genConsumeReg(src);
	unsigned destOffset = 0;
	unsigned srcOffset = 0;
	// Consume the destination address and source operands in proper evaluation order.
	genConsumeAddress(dest);
	genConsumeRegs(src);
	regNumber destReg = dest->isContained() ? REG_NA : dest->GetRegNum();
	regNumber srcReg = src->isContained() ? REG_NA : src->GetRegNum();
	unsigned destOffset = 0;
	unsigned srcOffset = 0;

[kg]

genConsumeOperands isn't usable here (it breaks) nor is genConsumeAddress (it breaks)

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

[kg]

The proposed lowering optimization breaks codegen somehow, I'm not sure why. Will poke at it more later.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.