Auto merge of #3879 - rust-lang:rustup-2024-09-12, r=RalfJung

Automatic Rustup

rust-version

@@ -1 +1 @@
-a9fb00bfa4b3038c855b2097b54e05e8c198c183
+6c65d4f47f82836f303026ec70f752e30d586bd4

src/intrinsics/simd.rs

@@ -666,22 +666,19 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 let (right, right_len) = this.operand_to_simd(right)?;
                 let (dest, dest_len) = this.mplace_to_simd(dest)?;
 
-                // `index` is an array, not a SIMD type
-                let ty::Array(_, index_len) = index.layout.ty.kind() else {
-                    span_bug!(
-                        this.cur_span(),
-                        "simd_shuffle index argument has non-array type {}",
-                        index.layout.ty
-                    )
+                // `index` is an array or a SIMD type
+                let (index, index_len) = match index.layout.ty.kind() {
+                    // FIXME: remove this once `index` must always be a SIMD vector.
+                    ty::Array(..) => (index.assert_mem_place(), index.len(this)?),
+                    _ => this.operand_to_simd(index)?,
                 };
-                let index_len = index_len.eval_target_usize(*this.tcx, this.param_env());
 
                 assert_eq!(left_len, right_len);
                 assert_eq!(index_len, dest_len);
 
                 for i in 0..dest_len {
                     let src_index: u64 = this
-                        .read_immediate(&this.project_index(index, i)?)?
+                        .read_immediate(&this.project_index(&index, i)?)?
                         .to_scalar()
                         .to_u32()?
                         .into();

tests/fail/intrinsics/ptr_offset_unsigned_overflow.rs

@@ -0,0 +1,7 @@
+fn main() {
+    let x = &[0i32; 2];
+    let x = x.as_ptr().wrapping_add(1);
+    // If the `!0` is interpreted as `isize`, it is just `-1` and hence harmless.
+    // However, this is unsigned arithmetic, so really this is `usize::MAX` and hence UB.
+    unsafe { x.byte_add(!0).read() }; //~ERROR: does not fit in an `isize`
+}

tests/fail/intrinsics/ptr_offset_unsigned_overflow.stderr

@@ -0,0 +1,15 @@
+error: Undefined Behavior: overflowing pointer arithmetic: the total offset in bytes does not fit in an `isize`
+  --> $DIR/ptr_offset_unsigned_overflow.rs:LL:CC
+   |
+LL |     unsafe { x.byte_add(!0).read() };
+   |              ^^^^^^^^^^^^^^ overflowing pointer arithmetic: the total offset in bytes does not fit in an `isize`
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at $DIR/ptr_offset_unsigned_overflow.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+

tests/pass/intrinsics/portable-simd.rs

@@ -620,6 +620,10 @@ fn simd_intrinsics() {
         );
         assert_eq!(simd_shuffle_generic::<_, i32x4, { &[3, 1, 0, 2] }>(a, b), a,);
         assert_eq!(simd_shuffle::<_, _, i32x4>(a, b, const { [3u32, 1, 0, 2] }), a,);
+        assert_eq!(
+            simd_shuffle::<_, _, i32x4>(a, b, const { u32x4::from_array([3u32, 1, 0, 2]) }),
+            a,
+        );
         assert_eq!(
             simd_shuffle_generic::<_, i32x4, { &[7, 5, 4, 6] }>(a, b),
             i32x4::from_array([4, 2, 1, 10]),
@@ -628,6 +632,10 @@ fn simd_intrinsics() {
             simd_shuffle::<_, _, i32x4>(a, b, const { [7u32, 5, 4, 6] }),
             i32x4::from_array([4, 2, 1, 10]),
         );
+        assert_eq!(
+            simd_shuffle::<_, _, i32x4>(a, b, const { u32x4::from_array([7u32, 5, 4, 6]) }),
+            i32x4::from_array([4, 2, 1, 10]),
+        );
     }
 }