Merge pull request #282 from RalfJung/ctfe-stress

CTFE stress benchmarks

Author: Mark-Simulacrum

collector/benchmarks/ctfe-stress-cast/src/lib.rs

@@ -1,5 +1,4 @@
 #![feature(const_fn, const_let)]
-#![allow(unused_must_use)]
 
 // Try to make CTFE actually do a lot of computation, without producing a big result.
 // And without support for loops.
@@ -41,8 +40,23 @@ macro_rules! const_repeat {
     }};
 }
 macro_rules! expensive_static {
-    ($name: ident : $T: ty = $e : expr) =>
-        (pub static $name : $T = const_repeat!([16 16 16 16 16 16] $e, $T);)
+    ($name: ident : $T: ty = $e : expr; $count: tt) =>
+        (pub static $name : $T = const_repeat!($count $e, $T);)
 }
 
-expensive_static!(UNSIZING: &'static [u8] = b"foo");
+pub trait Trait: Sync {}
+impl Trait for u32 {}
+
+const fn inc(i: i32) -> i32 { i + 1 }
+
+// The numbers in the brackets are iteration counts. E.g., [4 16 16] means
+// 4 * 16 * 16 = 2^(2+4+4) = 2^10 iterations.
+expensive_static!(CAST: usize = 42i32 as u8 as u64 as i8 as isize as usize; [8 16 16 16 16]);
+expensive_static!(CONST_FN: i32 = inc(42); [8 16 16 16 16]);
+expensive_static!(FIELDS: &'static i32 = &("bar", 42, "foo", 3.14).1; [8 16 16 16 16]);
+expensive_static!(FORCE_ALLOC: i32 = *****(&&&&&5); [8 16 16 16 16]);
+expensive_static!(CHECKED_INDEX: u8 = b"foomp"[3]; [8 16 16 16 16]);
+expensive_static!(OPS: i32 = ((((10 >> 1) + 3) * 7) / 2 - 12) << 4; [4 16 16 16 16]);
+expensive_static!(RELOCATIONS : &'static str = "hello"; [8 16 16 16 16]);
+expensive_static!(UNSIZE_SLICE: &'static [u8] = b"foo"; [4 16 16 16 16 16]);
+expensive_static!(UNSIZE_TRAIT: &'static Trait = &42u32; [4 16 16 16 16 16]);