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Add a no-f64 version of fmaf #875

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3 changes: 3 additions & 0 deletions ci/run.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -184,6 +184,8 @@ fi

mflags=()

nowiden_tests=$(grep -vE '^#' etc/has-nowiden-impl.txt | tr '\n' ' ')

# We enumerate features manually.
mflags+=(--no-default-features)

Expand Down Expand Up @@ -283,6 +285,7 @@ else
# Test the same in release mode, which also increases coverage. Also ensure
# the soft float routines are checked.
"${cmd[@]}" "$profile_flag" release-checked
[ -n "${nowiden_tests:-}" ] && LIBM_F32_NO_WIDEN=1 "${cmd[@]}" "$profile_flag" release-checked -- $nowiden_tests
"${cmd[@]}" "$profile_flag" release-checked --features force-soft-floats
"${cmd[@]}" "$profile_flag" release-checked --features unstable-intrinsics
"${cmd[@]}" "$profile_flag" release-checked --features unstable-intrinsics --benches
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2 changes: 2 additions & 0 deletions etc/has-nowiden-impl.txt
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@@ -0,0 +1,2 @@
# Functions that have a different version based on f32_no_widen
fmaf
10 changes: 10 additions & 0 deletions libm/configure.rs
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Expand Up @@ -50,6 +50,7 @@ pub fn emit_libm_config(cfg: &Config) {
emit_intrinsics_cfg();
emit_arch_cfg();
emit_optimization_cfg(cfg);
emit_widen_cfg(cfg);
emit_cfg_shorthands(cfg);
emit_cfg_env(cfg);
emit_f16_f128_cfg(cfg);
Expand Down Expand Up @@ -96,6 +97,15 @@ fn emit_optimization_cfg(cfg: &Config) {
}
}

fn emit_widen_cfg(_cfg: &Config) {
println!("cargo:rustc-check-cfg=cfg(f32_no_widen)");
println!("cargo:rerun-if-env-changed=LIBM_F32_NO_WIDEN");

if env::var_os("LIBM_F32_NO_WIDEN").is_some() {
println!("cargo:rustc-cfg=f32_no_widen");
}
}

/// Provide an alias for common longer config combinations.
fn emit_cfg_shorthands(cfg: &Config) {
println!("cargo:rustc-check-cfg=cfg(x86_no_sse)");
Expand Down
6 changes: 5 additions & 1 deletion libm/src/math/fma_wide.rs
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Expand Up @@ -23,7 +23,11 @@ pub fn fmaf(x: f32, y: f32, z: f32) -> f32 {
args: x, y, z,
}

fma_wide_round(x, y, z, Round::Nearest).val
if cfg!(f32_no_widen) {
super::fma::fma_round(x, y, z, Round::Nearest).val
} else {
fma_wide_round(x, y, z, Round::Nearest).val
}
}

/// Fma implementation when a hardware-backed larger float type is available. For `f32` and `f64`,
Expand Down
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