Rollup merge of rust-lang#105930 - JakobDegen:nal-unsound, r=oli-obk

Disable `NormalizeArrayLen`

cc rust-lang#105929

r? mir-opt

Author: matthiaskrgr

compiler/rustc_mir_transform/src/normalize_array_len.rs

@@ -16,7 +16,8 @@ pub struct NormalizeArrayLen;
 
 impl<'tcx> MirPass<'tcx> for NormalizeArrayLen {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 4
+        // See #105929
+        sess.mir_opt_level() >= 4 && sess.opts.unstable_opts.unsound_mir_opts
     }
 
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {

src/test/mir-opt/const_prop/slice_len.main.ConstProp.32bit.diff

@@ -12,7 +12,6 @@
       let mut _7: usize;                   // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _8: bool;                    // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _9: &[u32; 3];               // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-      let mut _10: &[u32; 3];              // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
 
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
@@ -25,16 +24,14 @@
                                            // + literal: Const { ty: &[u32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
           _4 = _9;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _3 = _4;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          StorageLive(_10);                // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          _10 = _3;                        // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _2 = move _3 as &[u32] (Pointer(Unsize)); // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           StorageDead(_3);                 // scope 0 at $DIR/slice_len.rs:+1:18: +1:19
           StorageLive(_6);                 // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
           _6 = const 1_usize;              // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
-          _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
-          StorageDead(_10);                // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
+-         _7 = Len((*_2));                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         _8 = Lt(_6, _7);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
++         _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         _8 = const true;                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         assert(const true, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 1_usize) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       }

src/test/mir-opt/const_prop/slice_len.main.ConstProp.64bit.diff

@@ -12,7 +12,6 @@
       let mut _7: usize;                   // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _8: bool;                    // in scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       let mut _9: &[u32; 3];               // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-      let mut _10: &[u32; 3];              // in scope 0 at $DIR/slice_len.rs:+1:6: +1:19
 
       bb0: {
           StorageLive(_1);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
@@ -25,16 +24,14 @@
                                            // + literal: Const { ty: &[u32; 3], val: Unevaluated(main, [], Some(promoted[0])) }
           _4 = _9;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _3 = _4;                         // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          StorageLive(_10);                // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
-          _10 = _3;                        // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           _2 = move _3 as &[u32] (Pointer(Unsize)); // scope 0 at $DIR/slice_len.rs:+1:6: +1:19
           StorageDead(_3);                 // scope 0 at $DIR/slice_len.rs:+1:18: +1:19
           StorageLive(_6);                 // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
           _6 = const 1_usize;              // scope 0 at $DIR/slice_len.rs:+1:31: +1:32
-          _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
-          StorageDead(_10);                // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
+-         _7 = Len((*_2));                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         _8 = Lt(_6, _7);                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 -         assert(move _8, "index out of bounds: the length is {} but the index is {}", move _7, _6) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
++         _7 = const 3_usize;              // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         _8 = const true;                 // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
 +         assert(const true, "index out of bounds: the length is {} but the index is {}", const 3_usize, const 1_usize) -> bb1; // scope 0 at $DIR/slice_len.rs:+1:5: +1:33
       }

src/test/mir-opt/issue_76432.test.SimplifyComparisonIntegral.diff

@@ -22,7 +22,6 @@
       let mut _20: *const T;               // in scope 0 at $DIR/issue_76432.rs:+3:70: +3:84
       let mut _21: *const T;               // in scope 0 at $DIR/issue_76432.rs:+3:70: +3:84
       let mut _22: !;                      // in scope 0 at $SRC_DIR/core/src/panic.rs:LL:COL
-      let mut _23: &[T; 3];                // in scope 0 at $DIR/issue_76432.rs:+1:19: +1:29
       scope 1 {
           debug v => _2;                   // in scope 1 at $DIR/issue_76432.rs:+1:9: +1:10
           let _13: &T;                     // in scope 1 at $DIR/issue_76432.rs:+3:10: +3:16
@@ -52,17 +51,16 @@
           StorageDead(_6);                 // scope 0 at $DIR/issue_76432.rs:+1:28: +1:29
           _4 = &_5;                        // scope 0 at $DIR/issue_76432.rs:+1:19: +1:29
           _3 = _4;                         // scope 0 at $DIR/issue_76432.rs:+1:19: +1:29
-          StorageLive(_23);                // scope 0 at $DIR/issue_76432.rs:+1:19: +1:29
-          _23 = _3;                        // scope 0 at $DIR/issue_76432.rs:+1:19: +1:29
           _2 = move _3 as &[T] (Pointer(Unsize)); // scope 0 at $DIR/issue_76432.rs:+1:19: +1:29
           StorageDead(_3);                 // scope 0 at $DIR/issue_76432.rs:+1:28: +1:29
           StorageDead(_4);                 // scope 0 at $DIR/issue_76432.rs:+1:29: +1:30
           StorageLive(_9);                 // scope 1 at $DIR/issue_76432.rs:+2:5: +5:6
-          _10 = const 3_usize;             // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
-          StorageDead(_23);                // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
+          _10 = Len((*_2));                // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
           _11 = const 3_usize;             // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
-          _12 = const true;                // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
-          goto -> bb2;                     // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
+-         _12 = Eq(move _10, const 3_usize); // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
+-         switchInt(move _12) -> [0: bb1, otherwise: bb2]; // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
++         nop;                             // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
++         switchInt(move _10) -> [3: bb2, otherwise: bb1]; // scope 1 at $DIR/issue_76432.rs:+3:9: +3:33
       }
 
       bb1: {

src/test/mir-opt/lower_array_len_e2e.rs

@@ -1,4 +1,4 @@
-// compile-flags: -Z mir-opt-level=4
+// compile-flags: -Z mir-opt-level=4 -Zunsound-mir-opts
 
 // EMIT_MIR lower_array_len_e2e.array_bound.PreCodegen.after.mir
 pub fn array_bound<const N: usize>(index: usize, slice: &[u8; N]) -> u8 {