Define UB in float-to-int casts to saturate

- Round to zero, and representable values cast directly.
- `NaN` goes to 0
- Values beyond the limits of the type are saturated to the "nearest value"
  (essentially rounding to zero, in some sense) in the integral type, so e.g.
  `f32::INFINITY` would go to `{u,i}N::MAX.`

1 files changed, 6 insertions, 6 deletions

diff --git a/src/test/codegen/unchecked-float-casts.rs b/src/test/codegen/unchecked-float-casts.rs
index 34e96122223..789feea12d6 100644
--- a/src/test/codegen/unchecked-float-casts.rs
+++ b/src/test/codegen/unchecked-float-casts.rs
@@ -1,7 +1,7 @@
-// compile-flags: -C no-prepopulate-passes
+// This file tests that we don't generate any code for saturation when using the
+// unchecked intrinsics.
 
-// This file tests that we don't generate any code for saturation if
-// -Z saturating-float-casts is not enabled.
+// compile-flags: -C opt-level=3
 
 #![crate_type = "lib"]
 
@@ -12,7 +12,7 @@ pub fn f32_to_u32(x: f32) -> u32 {
     // CHECK-NOT: fcmp
     // CHECK-NOT: icmp
     // CHECK-NOT: select
-    x as u32
+    unsafe { x.to_int_unchecked() }
 }
 
 // CHECK-LABEL: @f32_to_i32
@@ -22,7 +22,7 @@ pub fn f32_to_i32(x: f32) -> i32 {
     // CHECK-NOT: fcmp
     // CHECK-NOT: icmp
     // CHECK-NOT: select
-    x as i32
+    unsafe { x.to_int_unchecked() }
 }
 
 #[no_mangle]
@@ -31,5 +31,5 @@ pub fn f64_to_u16(x: f64) -> u16 {
     // CHECK-NOT: fcmp
     // CHECK-NOT: icmp
     // CHECK-NOT: select
-    x as u16
+    unsafe { x.to_int_unchecked() }
 }