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Enable SSE 4.2 unconditionally (#3833)

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* Enable SSE 4.2 unconditionally

Fuzzing over the weekend found that `i64x2` comparison operators
require `pcmpgtq` which is an SSE 4.2 instruction. Along the lines of #3816
this commit unconditionally enables and requires SSE 4.2 for compilation
and fuzzing. It will no longer be possible to create a compiler for
x86_64 with simd enabled if SSE 4.2 is disabled.

* Update comment
This commit is contained in:
Alex Crichton
2022-02-22 13:23:51 -06:00
committed by GitHub
parent 43d31c5bf7
commit 709f7e0c8a
4 changed files with 14 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
cranelift/codegen/meta/src/isa/x86.rs
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@@ -38,7 +38,7 @@ fn define_settings(shared: &SettingGroup) -> SettingGroup {
"has_sse42", "has_sse42",
"Has support for SSE4.2.", "Has support for SSE4.2.",
"SSE4.2: CPUID.01H:ECX.SSE4_2[bit 20]", "SSE4.2: CPUID.01H:ECX.SSE4_2[bit 20]",
false, true,
); );
let has_avx = settings.add_bool( let has_avx = settings.add_bool(
"has_avx", "has_avx",

11
cranelift/codegen/src/isa/x64/mod.rs
View File

@@ -178,11 +178,15 @@ fn isa_constructor(
let isa_flags = x64_settings::Flags::new(&shared_flags, builder); let isa_flags = x64_settings::Flags::new(&shared_flags, builder);
// Check for compatibility between flags and ISA level // Check for compatibility between flags and ISA level
// requested. In particular, SIMD support requires SSE4.1. // requested. In particular, SIMD support requires SSE4.2.
if shared_flags.enable_simd() { if shared_flags.enable_simd() {
if !isa_flags.has_sse3() || !isa_flags.has_ssse3() || !isa_flags.has_sse41() { if !isa_flags.has_sse3()
|| !isa_flags.has_ssse3()
|| !isa_flags.has_sse41()
|| !isa_flags.has_sse42()
{
return Err(CodegenError::Unsupported( return Err(CodegenError::Unsupported(
"SIMD support requires SSE3, SSSE3, and SSE4.1 on x86_64.".into(), "SIMD support requires SSE3, SSSE3, SSE4.1, and SSE4.2 on x86_64.".into(),
)); ));
} }
} }
@@ -354,6 +358,7 @@ mod test {
isa_builder.set("has_sse3", "false").unwrap(); isa_builder.set("has_sse3", "false").unwrap();
isa_builder.set("has_ssse3", "false").unwrap(); isa_builder.set("has_ssse3", "false").unwrap();
isa_builder.set("has_sse41", "false").unwrap(); isa_builder.set("has_sse41", "false").unwrap();
isa_builder.set("has_sse42", "false").unwrap();
assert!(matches!( assert!(matches!(
isa_builder.finish(shared_flags), isa_builder.finish(shared_flags),
Err(CodegenError::Unsupported(_)), Err(CodegenError::Unsupported(_)),

2
crates/fuzzing/src/generators.rs
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@@ -756,8 +756,8 @@ impl<'a> Arbitrary<'a> for CodegenSettings {
std:"sse3" => clif:"has_sse3" ratio: 1 in 1, std:"sse3" => clif:"has_sse3" ratio: 1 in 1,
std:"ssse3" => clif:"has_ssse3" ratio: 1 in 1, std:"ssse3" => clif:"has_ssse3" ratio: 1 in 1,
std:"sse4.1" => clif:"has_sse41" ratio: 1 in 1, std:"sse4.1" => clif:"has_sse41" ratio: 1 in 1,
std:"sse4.2" => clif:"has_sse42" ratio: 1 in 1,
std:"sse4.2" => clif:"has_sse42",
std:"popcnt" => clif:"has_popcnt", std:"popcnt" => clif:"has_popcnt",
std:"avx" => clif:"has_avx", std:"avx" => clif:"has_avx",
std:"avx2" => clif:"has_avx2", std:"avx2" => clif:"has_avx2",

4
crates/wasmtime/src/config.rs
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@@ -554,6 +554,10 @@ impl Config {
/// this does not enable the [relaxed simd proposal] as that is not /// this does not enable the [relaxed simd proposal] as that is not
/// implemented in Wasmtime at this time. /// implemented in Wasmtime at this time.
/// ///
/// On x86_64 platforms note that enabling this feature requires SSE 4.2 and
/// below to be available on the target platform. Compilation will fail if
/// the compile target does not include SSE 4.2.
///
/// This is `true` by default. /// This is `true` by default.
/// ///
/// [proposal]: https://github.com/webassembly/simd /// [proposal]: https://github.com/webassembly/simd