Heejin Ahn 735852f5ab [WebAssembly] Enable simd128 when relaxed-simd is set in AsmPrinter (#99803) ...

Even though in `Subtarget` we defined `SIMDLevel` as a number so
`hasRelaxedSIMD` automatically means `hasSIMD128`,
0caf0c93e7/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h (L36-L40)
0caf0c93e7/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h (L107)

specifying only `relaxed-simd` feature on a program that needs `simd128`
instructions to compile fails, because of this query in `AsmPrinter`:
d0d05aec3b/llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp (L644-L645)

This `verifyInstructionPredicates` function (and other functions called
by this function) is generated by

https://github.com/llvm/llvm-project/blob/main/llvm/utils/TableGen/InstrInfoEmitter.cpp,
and looks like this (you can check it in the
`lib/Target/WebAssembly/WebAssemblyGenInstrInfo.inc` in your build
directory):
```cpp
void verifyInstructionPredicates(
    unsigned Opcode, const FeatureBitset &Features) {
  FeatureBitset AvailableFeatures = computeAvailableFeatures(Features);
  FeatureBitset RequiredFeatures = computeRequiredFeatures(Opcode);
  FeatureBitset MissingFeatures =
      (AvailableFeatures & RequiredFeatures) ^
      RequiredFeatures;
  ...
}
```

And `computeAvailableFeatures` is just a set query, like this:
```cpp
inline FeatureBitset computeAvailableFeatures(const FeatureBitset &FB) {
  FeatureBitset Features;
  if (FB[WebAssembly::FeatureAtomics])
    Features.set(Feature_HasAtomicsBit);
  if (FB[WebAssembly::FeatureBulkMemory])
    Features.set(Feature_HasBulkMemoryBit);
  if (FB[WebAssembly::FeatureExceptionHandling])
    Features.set(Feature_HasExceptionHandlingBit);
  ...
```

So this is how currently `HasSIMD128` is defined:

0caf0c93e7/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td (L79-L81)

The things being checked in this `computeAvailableFeatures`, and in turn
in `AsmPrinter`, are `AssemblerPredicate`s. These only check which bits
are set in the features set and are different from `Predicate`s, which
can call `Subtarget` functions like `Subtarget->hasSIMD128()`.

But apparently we can use `all_of` and `any_of` directives in
`AssemblerPredicate`, and we can make `simd128`'s `AssemblerPredicate`
set in `relaxed-simd` is set by the condition as an 'or' of the two.

Fixes #98502.

2024-07-23 11:50:56 -07:00

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