[Wasm / RyuJit]: implement CKFINITE#129061
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Adds wasm codegen for the CKFINITE IL opcode, which throws
ArithmeticException if the float/double operand is NaN or +/-Inf and
otherwise passes the value through.
The check is implemented by computing "!(|x| < +Inf)". This is true for
NaN and +/-Inf and false for every finite value: for finite values
|x| < +Inf is 1; for +/-Inf it is 0; for NaN any wasm float comparison
other than "ne" returns 0. If the resulting bool is non-zero we jump to
the SCK_ARITH_EXCPN throw helper; otherwise the original value (left on
the wasm operand stack by genConsumeOperands) flows through as the
result.
To make the operand available twice (once for the abs+lt check and once
as the produced value), GT_CKFINITE is wired into the wasm multi-use
mechanism:
- Lowering::LowerCkfinite calls SetMultiplyUsed on op1, which triggers
the regalloc layer to allocate a temporary local and emit a
local.tee.
- WasmRegAlloc::CollectReferencesForNode releases the temporary local
once the GT_CKFINITE consumer is processed.
- CodeGen::genCkfinite emits the local.get + f{32,64}.abs +
f{32,64}.const +Inf + f{32,64}.lt + i32.eqz + br_if sequence and then
calls WasmProduceReg on the GT_CKFINITE node itself.
Fixes the NYI assert that was blocking R2R compilation of the
b25459 (JIT/Regression/CLR-x86-JIT/V1-M09.5-PDC) regression test on
wasm:
codegenwasm.cpp:878 Assertion failed 'CKFINITE' ... during
'Generate code'
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
This PR adds WebAssembly (RyuJIT) support for GT_CKFINITE by ensuring the operand can be re-read during codegen (via MultiplyUsed/temp locals) and emitting the Wasm finiteness check that throws on NaN / ±Inf.
Changes:
- Lowering: mark
GT_CKFINITEoperand asMultiplyUsedto enable re-reading during codegen. - Regalloc (Wasm): consume/release the temporary local allocated for the multiply-used operand at the
GT_CKFINITEuse site. - Codegen (Wasm): generate the finiteness check and branch to the arithmetic-exception throw helper when not finite.
Reviewed changes
Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| src/coreclr/jit/regallocwasm.cpp | Adds GT_CKFINITE handling to consume the temp local allocated for multiply-used operands. |
| src/coreclr/jit/lowerwasm.cpp | Introduces LowerCkfinite to mark the operand as multiply-used for Wasm codegen. |
| src/coreclr/jit/lower.h | Declares the new Wasm-only lowering helper LowerCkfinite. |
| src/coreclr/jit/lower.cpp | Wires GT_CKFINITE into the Wasm lowering switch. |
| src/coreclr/jit/codegenwasm.cpp | Adds GT_CKFINITE dispatch and implements genCkfinite Wasm emission logic. |
Comment on lines
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| // Push the operand value on the wasm stack. Because op1 was flagged as | ||
| // MultiplyUsed during lowering, "WasmProduceReg" will tee it into a | ||
| // temporary local so we can re-read it for the exponent check. | ||
| // | ||
| genConsumeOperands(treeNode->AsOp()); | ||
|
|
||
| // Re-read the operand to feed the finiteness check. | ||
| // | ||
| regNumber op1Reg = GetMultiUseOperandReg(op1); | ||
| emitter* emit = GetEmitter(); |
Comment on lines
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| // The operand value is still on the wasm stack from genConsumeOperands; | ||
| // produce it as the result of the GT_CKFINITE node. | ||
| // | ||
| WasmProduceReg(treeNode); |
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Adds wasm codegen for the CKFINITE.
Sequence here was shorter than masking off and testing the exponent, especially for doubles.