cranelift-native flags detection: fix flags on SSE2-only systems. #4231
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In bytecodealliance#4224 we saw that an SSE2-only x86-64 system somehow was still detecting SSE3/SSSE3/SSE4.1/SSE4.2. It turns out that we enabled these in the baseline `Flags` in bytecodealliance#3816, because without that, a ton of other things break: default flags no longer produce a compiler backend that works with default Wasmtime settings. However the logic to set them when detected (via `CPUID`-using feature-test macros) only does an "if detected then set bit" step per feature; the bits are never *cleared*. This PR fixes that.
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…ytecodealliance#4231) In bytecodealliance#4224 we saw that an SSE2-only x86-64 system somehow was still detecting SSE3/SSSE3/SSE4.1/SSE4.2. It turns out that we enabled these in the baseline `Flags` in bytecodealliance#3816, because without that, a ton of other things break: default flags no longer produce a compiler backend that works with default Wasmtime settings. However the logic to set them when detected (via `CPUID`-using feature-test macros) only does an "if detected then set bit" step per feature; the bits are never *cleared*. This PR fixes that.
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In #4224 we saw that an SSE2-only x86-64 system somehow was still
detecting SSE3/SSSE3/SSE4.1/SSE4.2. It turns out that we enabled these
in the baseline
Flagsin #3816, because without that, a ton of otherthings break: default flags no longer produce a compiler backend that
works with default Wasmtime settings. However the logic to set them when
detected (via
CPUID-using feature-test macros) only does an "ifdetected then set bit" step per feature; the bits are never cleared.
This PR fixes that.
This should be relatively temporary: once we fix #3810, then we can
remove this hack by making the default
Flagsstate all-zeroes again,as a compiler with default flags will again support a default Wasmtime.