Before this patch, running the x64 new backend would require both
compiling with --features experimental_x64 and running with
`use_new_backend`.
This patches changes this behavior so that the runtime flag is not
needed anymore: using the feature flag will enforce usage of the new
backend everywhere, making using and testing it much simpler:
cargo run --features experimental_x64 ;; other CLI options/flags
This also gives a hint at what the meta language generation would look
like after switching to the new backend.
Compiling only with the x64 codegen flag gives a nice compile time speedup.
This converts an `i32x4` into an `f32x4` with some rounding either by using an AVX512VL/F instruction--VCVTUDQ2PS--or a long sequence of SSE4.1 compatible instructions.
The `convert_i64x2_imul` custom legalization checks the ISA flags for AVX512DQ or AVX512VL support and legalizes `imul.i64x2` to an `x86_pmullq` in this case; if not, it uses a lengthy SSE2-compatible instruction sequence.
Accessing Wasm reference globals that are reference types will
want to use the plain load/store instructions. This commit adds
encodings for these instructions to match loading a i32/i64.
Producers of IR are required to insert the appropriate barriers
around the loads/stores.
This does a lot at once, since there was no clear way to split the three
commits:
- Instruction need to be passed an explicit InstructionFormat,
- InstructionFormat deduplication is checked once all entities have been
defined;
