Merge pull request rust-lang/libm#520 from tgross35/fma-restructure

Combine `fma` public API with its implementation

Author: tgross35

libm/crates/libm-test/src/f8_impl.rs

@@ -78,6 +78,10 @@ impl Float for f8 {
         libm::generic::copysign(self, other)
     }
 
+    fn fma(self, _y: Self, _z: Self) -> Self {
+        unimplemented!()
+    }
+
     fn normalize(_significand: Self::Int) -> (i32, Self::Int) {
         unimplemented!()
     }

libm/etc/function-definitions.json

@@ -130,8 +130,7 @@
     "copysign": {
         "sources": [
             "src/math/copysign.rs",
-            "src/math/generic/copysign.rs",
-            "src/math/support/float_traits.rs"
+            "src/math/generic/copysign.rs"
         ],
         "type": "f64"
     },
@@ -343,22 +342,19 @@
     },
     "fma": {
         "sources": [
-            "src/math/fma.rs",
-            "src/math/generic/fma.rs"
+            "src/math/fma.rs"
         ],
         "type": "f64"
     },
     "fmaf": {
         "sources": [
-            "src/math/fmaf.rs",
-            "src/math/generic/fma.rs"
+            "src/math/fma_wide.rs"
         ],
         "type": "f32"
     },
     "fmaf128": {
         "sources": [
-            "src/math/fmaf128.rs",
-            "src/math/generic/fma.rs"
+            "src/math/fma.rs"
         ],
         "type": "f128"
     },

libm/etc/update-api-list.py

@@ -24,7 +24,7 @@
 DIRECTORIES = [".github", "ci", "crates", "etc", "src"]
 
 # These files do not trigger a retest.
-IGNORED_SOURCES = ["src/libm_helper.rs"]
+IGNORED_SOURCES = ["src/libm_helper.rs", "src/math/support/float_traits.rs"]
 
 IndexTy: TypeAlias = dict[str, dict[str, Any]]
 """Type of the `index` item in rustdoc's JSON output"""

libm/src/math/cbrt.rs

@@ -103,11 +103,11 @@ pub fn cbrt_round(x: f64, round: Round) -> FpResult<f64> {
      * and rr an approximation of 1/zz. We now perform another iteration of
      * Newton-Raphson, this time with a linear approximation only. */
     y2 = y * y;
-    let mut y2l: f64 = fmaf64(y, y, -y2);
+    let mut y2l: f64 = y.fma(y, -y2);
 
     /* y2 + y2l = y^2 exactly */
     let mut y3: f64 = y2 * y;
-    let mut y3l: f64 = fmaf64(y, y2, -y3) + y * y2l;
+    let mut y3l: f64 = y.fma(y2, -y3) + y * y2l;
 
     /* y3 + y3l approximates y^3 with about 106 bits of accuracy */
     h = ((y3 - zz) + y3l) * rr;
@@ -132,9 +132,9 @@ pub fn cbrt_round(x: f64, round: Round) -> FpResult<f64> {
         cold_path();
 
         y2 = y1 * y1;
-        y2l = fmaf64(y1, y1, -y2);
+        y2l = y1.fma(y1, -y2);
         y3 = y2 * y1;
-        y3l = fmaf64(y1, y2, -y3) + y1 * y2l;
+        y3l = y1.fma(y2, -y3) + y1 * y2l;
         h = ((y3 - zz) + y3l) * rr;
         dy = h * (y1 * u0);
         y = y1 - dy;
@@ -198,18 +198,6 @@ pub fn cbrt_round(x: f64, round: Round) -> FpResult<f64> {
     FpResult::ok(f64::from_bits(cvt3))
 }
 
-fn fmaf64(x: f64, y: f64, z: f64) -> f64 {
-    #[cfg(intrinsics_enabled)]
-    {
-        return unsafe { core::intrinsics::fmaf64(x, y, z) };
-    }
-
-    #[cfg(not(intrinsics_enabled))]
-    {
-        return super::fma(x, y, z);
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use super::*;