Fix target-cpu fpu features on Armv7-R, Armv7-M, and Armv8-M

This is achieved by converting `+<fpu>,-d32,{,-fp64}` to `+<fpu>d16{,sp}`.

By using a single additive feature that captures `d16` vs `d32` and `sp` vs
`dp`, we prevent `-<feature>` from overriding `-C target-cpu` at build time.

Remove extraneous `-fp16` from `armv7r` targets, as this is not included in
`vfp3` anyway, but was preventing `fp16` from being enabled by e.g.,
`-C target-cpu=cortex-r7`, which does support `fp16`.
This commit is contained in:
Chris Copeland 2024-03-28 00:57:09 -07:00
parent 3d7e88148a
commit 0459e55375
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4 changed files with 9 additions and 11 deletions

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@ -22,7 +22,7 @@ pub fn target() -> Target {
linker: Some("rust-lld".into()),
relocation_model: RelocModel::Static,
panic_strategy: PanicStrategy::Abort,
features: "+vfp3,-d32,-fp16".into(),
features: "+vfp3d16".into(),
max_atomic_width: Some(64),
emit_debug_gdb_scripts: false,
// GCC defaults to 8 for arm-none here.

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@ -21,7 +21,7 @@ pub fn target() -> Target {
linker: Some("rust-lld".into()),
relocation_model: RelocModel::Static,
panic_strategy: PanicStrategy::Abort,
features: "+vfp3,-d32,-fp16".into(),
features: "+vfp3d16".into(),
max_atomic_width: Some(64),
emit_debug_gdb_scripts: false,
// GCC defaults to 8 for arm-none here.

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@ -25,16 +25,15 @@ pub fn target() -> Target {
options: TargetOptions {
abi: "eabihf".into(),
// `+vfp4` is the lowest common denominator between the Cortex-M4 (vfp4-16) and the
// Cortex-M7 (vfp5)
// `-d32` both the Cortex-M4 and the Cortex-M7 only have 16 double-precision registers
// available
// `-fp64` The Cortex-M4 only supports single precision floating point operations
// whereas in the Cortex-M7 double precision is optional
// vfp4 is the lowest common denominator between the Cortex-M4F (vfp4) and the
// Cortex-M7 (vfp5).
// Both the Cortex-M4 and the Cortex-M7 only have 16 double-precision registers
// available, and the Cortex-M4 only supports single-precision floating point operations
// whereas in the Cortex-M7 double-precision is optional.
//
// Reference:
// ARMv7-M Architecture Reference Manual - A2.5 The optional floating-point extension
features: "+vfp4,-d32,-fp64".into(),
features: "+vfp4d16sp".into(),
max_atomic_width: Some(32),
..base::thumb::opts()
},

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@ -22,8 +22,7 @@ pub fn target() -> Target {
// processor, the Cortex-M33 Technical Reference Manual states that
// the FPU uses the FPv5 architecture, single-precision instructions
// and 16 D registers.
// These parameters map to the following LLVM features.
features: "+fp-armv8,-fp64,-d32".into(),
features: "+fp-armv8d16sp".into(),
max_atomic_width: Some(32),
..base::thumb::opts()
},