Merge pull request #4252 from rust-lang/rustup-2025-04-07

Automatic Rustup

Author: RalfJung

bench-cargo-miri/big-allocs/src/main.rs

@@ -7,7 +7,10 @@ fn main() {
     // We can't use too big of an allocation or this code will encounter an allocation failure in
     // CI. Since the allocation can't be huge, we need to do a few iterations so that the effect
     // we're trying to measure is clearly visible above the interpreter's startup time.
-    for _ in 0..10 {
+    // FIXME (https://github.com/rust-lang/miri/issues/4253): On 32bit targets, we can run out of
+    // usable addresses if we don't reuse, leading to random test failures.
+    let count = if cfg!(target_pointer_width = "32") { 8 } else { 12 };
+    for _ in 0..count {
         drop(Vec::<u8>::with_capacity(512 * 1024 * 1024));
     }
 }

rust-version

@@ -1 +1 @@
-d5b4c2e4f19b6d7037371cdaecc3cc2c701c68df
+25a615bf829b9f6d6f22da537e3851043f92e5f2

src/intrinsics/mod.rs

@@ -411,9 +411,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 };
                 let res = this.binary_op(op, &a, &b)?;
                 // `binary_op` already called `generate_nan` if needed.
-                // Apply a relative error of 16ULP to simulate non-deterministic precision loss
+                // Apply a relative error of 4ULP to simulate non-deterministic precision loss
                 // due to optimizations.
-                let res = apply_random_float_error_to_imm(this, res, 4 /* log2(16) */)?;
+                let res = apply_random_float_error_to_imm(this, res, 2 /* log2(4) */)?;
                 this.write_immediate(*res, dest)?;
             }
 
@@ -464,9 +464,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 if !float_finite(&res)? {
                     throw_ub_format!("`{intrinsic_name}` intrinsic produced non-finite value as result");
                 }
-                // Apply a relative error of 16ULP to simulate non-deterministic precision loss
+                // Apply a relative error of 4ULP to simulate non-deterministic precision loss
                 // due to optimizations.
-                let res = apply_random_float_error_to_imm(this, res, 4 /* log2(16) */)?;
+                let res = apply_random_float_error_to_imm(this, res, 2 /* log2(4) */)?;
                 this.write_immediate(*res, dest)?;
             }
 

tests/pass/float.rs

@@ -38,8 +38,9 @@ macro_rules! assert_approx_eq {
     }};
 
     ($a:expr, $b: expr) => {
-        // accept up to 64ULP (16ULP for host floats and 16ULP for miri artificial error and 32 for any rounding errors)
-        assert_approx_eq!($a, $b, 64);
+        // accept up to 12ULP (4ULP for host floats and 4ULP for miri artificial error and 4 for any additional effects
+        // due to having multiple error sources.
+        assert_approx_eq!($a, $b, 12);
     };
 }