From 128e572054342be4bffc283bf235cfa17c7f5640 Mon Sep 17 00:00:00 2001
From: Trevor Gross <tmgross@umich.edu>
Date: Wed, 16 Oct 2024 22:56:28 -0500
Subject: [PATCH] Add a helper for cached test inputs

Add a type that caches values used to implement `GenerateInput` on a
variety of signatures.
---
 .../libm/crates/libm-test/src/gen.rs          | 71 +++++++++++++++++++
 .../libm/crates/libm-test/src/lib.rs          |  1 +
 2 files changed, 72 insertions(+)
 create mode 100644 library/compiler-builtins/libm/crates/libm-test/src/gen.rs

diff --git a/library/compiler-builtins/libm/crates/libm-test/src/gen.rs b/library/compiler-builtins/libm/crates/libm-test/src/gen.rs
new file mode 100644
index 000000000000..12e17d476538
--- /dev/null
+++ b/library/compiler-builtins/libm/crates/libm-test/src/gen.rs
@@ -0,0 +1,71 @@
+//! Different generators that can create random or systematic bit patterns.
+
+use crate::GenerateInput;
+
+/// Helper type to turn any reusable input into a generator.
+#[derive(Clone, Debug, Default)]
+pub struct CachedInput {
+    pub inputs_f32: Vec<(f32, f32, f32)>,
+    pub inputs_f64: Vec<(f64, f64, f64)>,
+    pub inputs_i32: Vec<(i32, i32, i32)>,
+}
+
+impl GenerateInput<(f32,)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f32,)> {
+        self.inputs_f32.iter().map(|f| (f.0,))
+    }
+}
+
+impl GenerateInput<(f32, f32)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f32, f32)> {
+        self.inputs_f32.iter().map(|f| (f.0, f.1))
+    }
+}
+
+impl GenerateInput<(i32, f32)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (i32, f32)> {
+        self.inputs_i32.iter().zip(self.inputs_f32.iter()).map(|(i, f)| (i.0, f.0))
+    }
+}
+
+impl GenerateInput<(f32, i32)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f32, i32)> {
+        GenerateInput::<(i32, f32)>::get_cases(self).map(|(i, f)| (f, i))
+    }
+}
+
+impl GenerateInput<(f32, f32, f32)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f32, f32, f32)> {
+        self.inputs_f32.iter().copied()
+    }
+}
+
+impl GenerateInput<(f64,)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f64,)> {
+        self.inputs_f64.iter().map(|f| (f.0,))
+    }
+}
+
+impl GenerateInput<(f64, f64)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f64, f64)> {
+        self.inputs_f64.iter().map(|f| (f.0, f.1))
+    }
+}
+
+impl GenerateInput<(i32, f64)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (i32, f64)> {
+        self.inputs_i32.iter().zip(self.inputs_f64.iter()).map(|(i, f)| (i.0, f.0))
+    }
+}
+
+impl GenerateInput<(f64, i32)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f64, i32)> {
+        GenerateInput::<(i32, f64)>::get_cases(self).map(|(i, f)| (f, i))
+    }
+}
+
+impl GenerateInput<(f64, f64, f64)> for CachedInput {
+    fn get_cases(&self) -> impl Iterator<Item = (f64, f64, f64)> {
+        self.inputs_f64.iter().copied()
+    }
+}
diff --git a/library/compiler-builtins/libm/crates/libm-test/src/lib.rs b/library/compiler-builtins/libm/crates/libm-test/src/lib.rs
index 41873099f637..fc5385ecbc29 100644
--- a/library/compiler-builtins/libm/crates/libm-test/src/lib.rs
+++ b/library/compiler-builtins/libm/crates/libm-test/src/lib.rs
@@ -1,3 +1,4 @@
+pub mod gen;
 mod num_traits;
 mod test_traits;