Scale test iteration count at a later point

Currently the argument multiplier and large float multiplier happen
before selecting count based on generator. However, this means that
bivariate and trivariate functions don't get scaled at all (except for
the special cased fma).

Move this scaling to a later point.

Author: tgross35

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

@@ -23,8 +23,8 @@ static EXTENSIVE_ITER_OVERRIDE: LazyLock<Option<u64>> = LazyLock::new(|| {
 ///
 /// Contains the itentifier+generator combo to match on, plus the factor to reduce by.
 const EXTEMELY_SLOW_TESTS: &[(Identifier, GeneratorKind, u64)] = &[
-    (Identifier::Fmodf128, GeneratorKind::QuickSpaced, 40),
-    (Identifier::Fmodf128, GeneratorKind::Extensive, 40),
+    (Identifier::Fmodf128, GeneratorKind::QuickSpaced, 50),
+    (Identifier::Fmodf128, GeneratorKind::Extensive, 50),
 ];
 
 /// Maximum number of iterations to run for a single routine.
@@ -200,15 +200,6 @@ pub fn iteration_count(ctx: &CheckCtx, argnum: usize) -> u64 {
         domain_iter_count = 100_000;
     }
 
-    // Larger float types get more iterations.
-    if t_env.large_float_ty {
-        domain_iter_count *= 4;
-    }
-
-    // Functions with more arguments get more iterations.
-    let arg_multiplier = 1 << (t_env.input_count - 1);
-    domain_iter_count *= arg_multiplier;
-
     // If we will be running tests against MPFR, we don't need to test as much against musl.
     // However, there are some platforms where we have to test against musl since MPFR can't be
     // built.
@@ -228,6 +219,25 @@ pub fn iteration_count(ctx: &CheckCtx, argnum: usize) -> u64 {
         }
     };
 
+    // Larger float types get more iterations.
+    if t_env.large_float_ty && ctx.gen_kind != GeneratorKind::Extensive {
+        if ctx.gen_kind == GeneratorKind::Extensive {
+            // Extensive already has a pretty high test count.
+            total_iterations *= 2;
+        } else {
+            total_iterations *= 4;
+        }
+    }
+
+    // Functions with more arguments get more iterations.
+    let arg_multiplier = 1 << (t_env.input_count - 1);
+    total_iterations *= arg_multiplier;
+
+    // FMA has a huge domain but is reasonably fast to run, so increase another 1.5x.
+    if ctx.base_name == BaseName::Fma {
+        total_iterations = 3 * total_iterations / 2;
+    }
+
     // Some tests are significantly slower than others and need to be further reduced.
     if let Some((_id, _gen, scale)) = EXTEMELY_SLOW_TESTS
         .iter()
@@ -239,11 +249,6 @@ pub fn iteration_count(ctx: &CheckCtx, argnum: usize) -> u64 {
         }
     }
 
-    // FMA has a huge domain but is reasonably fast to run, so increase iterations.
-    if ctx.base_name == BaseName::Fma {
-        total_iterations *= 4;
-    }
-
     if cfg!(optimizations_enabled) {
         // Always run at least 10,000 tests.
         total_iterations = total_iterations.max(10_000);