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add more s390x target features

The target feature names are, right now, based on the llvm target feature names. These mostly line up well with the names of [Facility Inidications](https://publibfp.dhe.ibm.com/epubs/pdf/a227832d.pdf#page=301) names. The linux kernel uses shorter, more cryptic names. (e.g. "vector" is `vx`). We can deviate from the llvm names, but the CPU vendor (IBM) does not appear to use e.g. `vx` for what they call `vector`.

There are a number of implied target features between the vector facilities (based on the [Facility Inidications](https://publibfp.dhe.ibm.com/epubs/pdf/a227832d.pdf#page=301) table):

- 129 The vector facility for z/Architecture is installed in the z/Architecture architectural mode.
- 134 The vector packed decimal facility is installed in the z/Architecture architectural mode. When bit 134 is one, bit 129 is also one.
- 135 The vector enhancements facility 1 is installed in the z/Architecture architectural mode. When bit 135 is one, bit 129 is also one.
- 148 The vector-enhancements facility 2 is installed in the z/Architecture architectural mode. When bit 148 is one, bits 129 and 135 are also one.
- 152 The vector-packed-decimal-enhancement facility 1 is installed in the z/Architecture architectural mode. When bit 152 is one, bits 129 and 134 are also one.
- 165 The neural-network-processing-assist facility is installed in the z/Architecture architectural mode. When bit 165 is one, bit 129 is also one.
- 192 The vector-packed-decimal-enhancement facility 2 is installed in the z/Architecture architectural mode. When bit 192 is one, bits 129, 134, and 152 are also one.

And then there are a number of facilities without any implied target features

- 45 The distinct-operands, fast-BCR-serialization, high-word, and population-count facilities, the interlocked-access facility 1, and the load/store-oncondition facility 1 are installed in the z/Architecture architectural mode.
- 73 The transactional-execution facility is installed in the z/Architecture architectural mode. Bit 49 is one when bit 73 is one.
- 133 The guarded-storage facility is installed in the z/Architecture architectural mode.
- 150 The enhanced-sort facility is installed in the z/Architecture architectural mode.
- 151 The DEFLATE-conversion facility is installed in the z/Architecture architectural mode.

The added target features are those that have ISA implications, can be queried at runtime, and have LLVM support. LLVM [defines more target features](d49a2d2bc9/llvm/lib/Target/SystemZ/SystemZFeatures.td), but I'm not sure those are useful. They can always be added later, and can already be set globally using `-Ctarget-feature`.
This commit is contained in:
Folkert de Vries 2025-01-17 14:57:18 +01:00
parent f04bbc60f8
commit 69c7e1d02f
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2 changed files with 31 additions and 1 deletions

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@ -611,7 +611,26 @@ static LOONGARCH_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
const IBMZ_FEATURES: &[(&str, Stability, ImpliedFeatures)] = &[
// tidy-alphabetical-start
("backchain", Unstable(sym::s390x_target_feature), &[]),
("deflate-conversion", Unstable(sym::s390x_target_feature), &[]),
("enhanced-sort", Unstable(sym::s390x_target_feature), &[]),
("guarded-storage", Unstable(sym::s390x_target_feature), &[]),
("high-word", Unstable(sym::s390x_target_feature), &[]),
("nnp-assist", Unstable(sym::s390x_target_feature), &["vector"]),
("transactional-execution", Unstable(sym::s390x_target_feature), &[]),
("vector", Unstable(sym::s390x_target_feature), &[]),
("vector-enhancements-1", Unstable(sym::s390x_target_feature), &["vector"]),
("vector-enhancements-2", Unstable(sym::s390x_target_feature), &["vector-enhancements-1"]),
("vector-packed-decimal", Unstable(sym::s390x_target_feature), &["vector"]),
(
"vector-packed-decimal-enhancement",
Unstable(sym::s390x_target_feature),
&["vector-packed-decimal"],
),
(
"vector-packed-decimal-enhancement-2",
Unstable(sym::s390x_target_feature),
&["vector-packed-decimal-enhancement"],
),
// tidy-alphabetical-end
];
@ -768,7 +787,7 @@ impl Target {
/// the first list contains target features that must be enabled for ABI reasons,
/// and the second list contains target feature that must be disabled for ABI reasons.
///
/// These features are automatically appended to whatever the target spec sats as default
/// These features are automatically appended to whatever the target spec sets as default
/// features for the target.
///
/// All features enabled/disabled via `-Ctarget-features` and `#[target_features]` are checked