Switch to changing cp_non_overlap in tform

It was suggested to lower this in MIR instead of ssa, so do that instead.

compiler/rustc_codegen_ssa/src/mir/block.rs

@@ -643,23 +643,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
 
         match intrinsic {
             None | Some(sym::drop_in_place) => {}
-            Some(sym::copy_nonoverlapping) => {
-                bx = self.codegen_statement(
-                    bx,
-                    &rustc_middle::mir::Statement {
-                        source_info: rustc_middle::mir::SourceInfo::outermost(span),
-                        kind: rustc_middle::mir::StatementKind::CopyNonOverlapping(
-                            box rustc_middle::mir::CopyNonOverlapping {
-                                src: args[0].clone(),
-                                dst: args[1].clone(),
-                                count: args[2].clone(),
-                            },
-                        ),
-                    },
-                );
-                helper.funclet_br(self, &mut bx, destination.unwrap().1);
-                return;
-            }
+            Some(sym::copy_nonoverlapping) => unreachable!(),
             Some(intrinsic) => {
                 let dest = match ret_dest {
                     _ if fn_abi.ret.is_indirect() => llargs[0],
@@ -702,7 +686,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                     })
                     .collect();
 
-                self.codegen_intrinsic_call(
+                Self::codegen_intrinsic_call(
                     &mut bx,
                     *instance.as_ref().unwrap(),
                     &fn_abi,

compiler/rustc_codegen_ssa/src/mir/intrinsic.rs

@@ -49,7 +49,6 @@ fn memset_intrinsic<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     pub fn codegen_intrinsic_call(
-        &self,
         bx: &mut Bx,
         instance: ty::Instance<'tcx>,
         fn_abi: &FnAbi<'tcx, Ty<'tcx>>,
@@ -126,11 +125,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 let offset = args[1].immediate();
                 bx.gep(ptr, &[offset])
             }
-
-            sym::copy_nonoverlapping => {
-                // handled explicitly in compiler/rustc_codegen_ssa/src/mir/block.rs
-                unreachable!();
-            }
             sym::copy => {
                 copy_intrinsic(
                     bx,

compiler/rustc_middle/src/mir/mod.rs

@@ -1682,7 +1682,7 @@ pub struct Coverage {
     pub code_region: Option<CodeRegion>,
 }
 
-#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, HashStable, TypeFoldable)]
+#[derive(Clone, Debug, PartialEq, TyEncodable, TyDecodable, Hash, HashStable, TypeFoldable)]
 pub struct CopyNonOverlapping<'tcx> {
     pub src: Operand<'tcx>,
     pub dst: Operand<'tcx>,

compiler/rustc_mir/src/borrow_check/mod.rs

@@ -628,13 +628,19 @@ impl<'cx, 'tcx> dataflow::ResultsVisitor<'cx, 'tcx> for MirBorrowckCtxt<'cx, 'tc
             }
 
             StatementKind::CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping {
+                ..
+                /*
                 src,
                 dst,
                 count,
+                */
             }) => {
+                unreachable!()
+                /*
                 self.consume_operand(location, (src, span), flow_state);
                 self.consume_operand(location, (dst, span), flow_state);
                 self.consume_operand(location, (count, span), flow_state);
+                */
             }
             StatementKind::Nop
             | StatementKind::Coverage(..)

compiler/rustc_mir/src/interpret/intrinsics.rs

@@ -323,7 +323,10 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let result = Scalar::from_uint(truncated_bits, layout.size);
                 self.write_scalar(result, dest)?;
             }
-            sym::copy | sym::copy_nonoverlapping => {
+            sym::copy_nonoverlapping => {
+                self.copy_nonoverlapping(args[0], args[1], args[2])?;
+            }
+            sym::copy => {
                 let elem_ty = instance.substs.type_at(0);
                 let elem_layout = self.layout_of(elem_ty)?;
                 let count = self.read_scalar(&args[2])?.to_machine_usize(self)?;
@@ -338,12 +341,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let dest = self.memory.check_ptr_access(dest, size, elem_align)?;
 
                 if let (Some(src), Some(dest)) = (src, dest) {
-                    self.memory.copy(
-                        src,
-                        dest,
-                        size,
-                        intrinsic_name == sym::copy_nonoverlapping,
-                    )?;
+                    self.memory.copy(src, dest, size, false)?;
                 }
             }
             sym::offset => {

compiler/rustc_mir/src/interpret/step.rs

@@ -2,6 +2,7 @@
 //!
 //! The main entry point is the `step` method.
 
+use crate::interpret::OpTy;
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::{InterpResult, Scalar};
 use rustc_target::abi::LayoutOf;
@@ -115,35 +116,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
             // Call CopyNonOverlapping
             CopyNonOverlapping(box rustc_middle::mir::CopyNonOverlapping { dst, src, count }) => {
-                let (src, size) = {
-                    let src = self.eval_operand(src, None)?;
-                    let size = src.layout.layout.size;
-                    let mplace = *src.assert_mem_place(self);
-                    let ptr = match mplace.ptr {
-                        Scalar::Ptr(ptr) => ptr,
-                        _ => panic!(),
-                    };
-                    (ptr, size)
-                };
-
-                let dst = {
-                    let dst = self.eval_operand(dst, None)?;
-                    let mplace = *dst.assert_mem_place(self);
-                    match mplace.ptr {
-                        Scalar::Ptr(ptr) => ptr,
-                        _ => panic!(),
-                    }
-                };
-
                 let count = self.eval_operand(count, None)?;
-                let count = self.read_immediate(count)?.to_scalar()?;
-                let count = if let Scalar::Int(i) = count {
-                    core::convert::TryFrom::try_from(i).unwrap()
-                } else {
-                    panic!();
-                };
 
-                self.memory.copy_repeatedly(src, dst, size, count, /*nonoverlapping*/ true)?;
+                let src = self.eval_operand(src, None)?;
+                let dst = self.eval_operand(dst, None)?;
+                self.copy_nonoverlapping(src, dst, count)?;
             }
 
             // Statements we do not track.
@@ -173,6 +150,31 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         Ok(())
     }
 
+    pub(crate) fn copy_nonoverlapping(
+        &mut self,
+        src: OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
+        dst: OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
+        count: OpTy<'tcx, <M as Machine<'mir, 'tcx>>::PointerTag>,
+    ) -> InterpResult<'tcx> {
+        let count = self.read_scalar(&count)?.to_machine_usize(self)?;
+        let layout = self.layout_of(src.layout.ty.builtin_deref(true).unwrap().ty)?;
+        let (size, align) = (layout.size, layout.align.abi);
+        let src =
+            self.memory.check_ptr_access(self.read_scalar(&src)?.check_init()?, size, align)?;
+
+        let dst =
+            self.memory.check_ptr_access(self.read_scalar(&dst)?.check_init()?, size, align)?;
+
+        let size = size.checked_mul(count, self).ok_or_else(|| {
+            err_ub_format!("overflow computing total size of `copy_nonoverlapping`")
+        })?;
+
+        if let (Some(src), Some(dst)) = (src, dst) {
+            self.memory.copy(src, dst, size, /*nonoverlapping*/ true)?;
+        }
+        Ok(())
+    }
+
     /// Evaluate an assignment statement.
     ///
     /// There is no separate `eval_rvalue` function. Instead, the code for handling each rvalue

compiler/rustc_mir/src/transform/check_unsafety.rs

@@ -115,7 +115,6 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
             | StatementKind::Retag { .. }
             | StatementKind::AscribeUserType(..)
             | StatementKind::Coverage(..)
-            | StatementKind::CopyNonOverlapping(..)
             | StatementKind::Nop => {
                 // safe (at least as emitted during MIR construction)
             }
@@ -124,6 +123,7 @@ impl<'a, 'tcx> Visitor<'tcx> for UnsafetyChecker<'a, 'tcx> {
                 UnsafetyViolationKind::General,
                 UnsafetyViolationDetails::UseOfInlineAssembly,
             ),
+            StatementKind::CopyNonOverlapping(..) => unreachable!(),
         }
         self.super_statement(statement, location);
     }

compiler/rustc_mir/src/transform/lower_intrinsics.rs

@@ -40,6 +40,27 @@ impl<'tcx> MirPass<'tcx> for LowerIntrinsics {
                             terminator.kind = TerminatorKind::Goto { target };
                         }
                     }
+                    sym::copy_nonoverlapping => {
+                        let target = destination.unwrap().1;
+                        let mut args = args.drain(..);
+                        block.statements.push(Statement {
+                            source_info: terminator.source_info,
+                            kind: StatementKind::CopyNonOverlapping(
+                                box rustc_middle::mir::CopyNonOverlapping {
+                                    src: args.next().unwrap(),
+                                    dst: args.next().unwrap(),
+                                    count: args.next().unwrap(),
+                                },
+                            ),
+                        });
+                        assert_eq!(
+                            args.next(),
+                            None,
+                            "Extra argument for copy_non_overlapping intrinsic"
+                        );
+                        drop(args);
+                        terminator.kind = TerminatorKind::Goto { target };
+                    }
                     sym::wrapping_add | sym::wrapping_sub | sym::wrapping_mul => {
                         if let Some((destination, target)) = *destination {
                             let lhs;

compiler/rustc_mir/src/transform/remove_noop_landing_pads.rs

@@ -39,7 +39,6 @@ impl RemoveNoopLandingPads {
                 | StatementKind::StorageDead(_)
                 | StatementKind::AscribeUserType(..)
                 | StatementKind::Coverage(..)
-                | StatementKind::CopyNonOverlapping(..)
                 | StatementKind::Nop => {
                     // These are all nops in a landing pad
                 }
@@ -56,6 +55,7 @@ impl RemoveNoopLandingPads {
                 StatementKind::Assign { .. }
                 | StatementKind::SetDiscriminant { .. }
                 | StatementKind::LlvmInlineAsm { .. }
+                | StatementKind::CopyNonOverlapping(..)
                 | StatementKind::Retag { .. } => {
                     return false;
                 }

src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs

@@ -224,7 +224,7 @@ fn check_statement(tcx: TyCtxt<'tcx>, body: &Body<'tcx>, def_id: DefId, statemen
           check_operand(tcx, dst, span, body)?;
           check_operand(tcx, src, span, body)?;
           check_operand(tcx, count, span, body)
-        },
+        }
         // These are all NOPs
         StatementKind::StorageLive(_)
         | StatementKind::StorageDead(_)