diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 99eecb567f277..42ad7cc9f806e 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -17,9 +17,7 @@ use rustc_middle::mir::visit::Visitor;
use rustc_middle::mir::*;
use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
use rustc_middle::ty::GenericArgs;
-use rustc_middle::ty::{
- self, ConstInt, Instance, ParamEnv, ScalarInt, Ty, TyCtxt, TypeVisitableExt,
-};
+use rustc_middle::ty::{self, Instance, ParamEnv, Ty, TyCtxt, TypeVisitableExt};
use rustc_span::Span;
use rustc_target::abi::{HasDataLayout, Size, TargetDataLayout};
@@ -312,43 +310,16 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
right: &Operand<'tcx>,
location: Location,
) -> Option<()> {
+ if matches!(op, BinOp::Shr | BinOp::Shl) {
+ // Shifts are linted in check_assertion() not here
+ return None;
+ }
+
let r = self.use_ecx(location, |this| {
this.ecx.read_immediate(&this.ecx.eval_operand(right, None)?)
});
let l = self
.use_ecx(location, |this| this.ecx.read_immediate(&this.ecx.eval_operand(left, None)?));
- // Check for exceeding shifts *even if* we cannot evaluate the LHS.
- if matches!(op, BinOp::Shr | BinOp::Shl) {
- let r = r.clone()?;
- // We need the type of the LHS. We cannot use `place_layout` as that is the type
- // of the result, which for checked binops is not the same!
- let left_ty = left.ty(self.local_decls(), self.tcx);
- let left_size = self.ecx.layout_of(left_ty).ok()?.size;
- let right_size = r.layout.size;
- let r_bits = r.to_scalar().to_bits(right_size).ok();
- if r_bits.is_some_and(|b| b >= left_size.bits() as u128) {
- debug!("check_binary_op: reporting assert for {:?}", location);
- let source_info = self.body().source_info(location);
- let panic = AssertKind::Overflow(
- op,
- match l {
- Some(l) => l.to_const_int(),
- // Invent a dummy value, the diagnostic ignores it anyway
- None => ConstInt::new(
- ScalarInt::try_from_uint(1_u8, left_size).unwrap(),
- left_ty.is_signed(),
- left_ty.is_ptr_sized_integral(),
- ),
- },
- r.to_const_int(),
- );
- self.report_assert_as_lint(
- source_info,
- AssertLint::ArithmeticOverflow(source_info.span, panic),
- );
- return None;
- }
- }
if let (Some(l), Some(r)) = (l, r) {
// The remaining operators are handled through `overflowing_binary_op`.
@@ -485,18 +456,30 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
.and_then(|op| self.ecx.read_immediate(&op).ok())
.map_or(DbgVal::Underscore, |op| DbgVal::Val(op.to_const_int()))
};
- let msg = match msg {
- AssertKind::DivisionByZero(op) => AssertKind::DivisionByZero(eval_to_int(op)),
- AssertKind::RemainderByZero(op) => AssertKind::RemainderByZero(eval_to_int(op)),
+ let (msg, emit_overflow_lint) = match msg {
+ AssertKind::DivisionByZero(op) => {
+ (AssertKind::DivisionByZero(eval_to_int(op)), false)
+ }
+ AssertKind::RemainderByZero(op) => {
+ (AssertKind::RemainderByZero(eval_to_int(op)), false)
+ }
AssertKind::Overflow(bin_op @ (BinOp::Div | BinOp::Rem), op1, op2) => {
// Division overflow is *UB* in the MIR, and different than the
// other overflow checks.
- AssertKind::Overflow(*bin_op, eval_to_int(op1), eval_to_int(op2))
+ (AssertKind::Overflow(*bin_op, eval_to_int(op1), eval_to_int(op2)), false)
+ }
+ AssertKind::Overflow(bin_op @ (BinOp::Shl | BinOp::Shr), op1, op2) => {
+ // A hack that fixes #117949
+ // Ideally check_binary_op() should check these shift ops,
+ // but it can't because they are getting removed from the MIR
+ // during const promotion. So we check the associated asserts
+ // here instead as they are not removed by promotion.
+ (AssertKind::Overflow(*bin_op, eval_to_int(op1), eval_to_int(op2)), true)
}
AssertKind::BoundsCheck { ref len, ref index } => {
let len = eval_to_int(len);
let index = eval_to_int(index);
- AssertKind::BoundsCheck { len, index }
+ (AssertKind::BoundsCheck { len, index }, false)
}
// Remaining overflow errors are already covered by checks on the binary operators.
AssertKind::Overflow(..) | AssertKind::OverflowNeg(_) => return None,
@@ -506,7 +489,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
let source_info = self.body().source_info(location);
self.report_assert_as_lint(
source_info,
- AssertLint::UnconditionalPanic(source_info.span, msg),
+ if emit_overflow_lint {
+ AssertLint::ArithmeticOverflow(source_info.span, msg)
+ } else {
+ AssertLint::UnconditionalPanic(source_info.span, msg)
+ },
);
}
diff --git a/tests/ui/lint/lint-exceeding-bitshifts.opt.stderr b/tests/ui/lint/lint-exceeding-bitshifts.opt.stderr
index 3a84c6c1fb1f9..77cea4b495235 100644
--- a/tests/ui/lint/lint-exceeding-bitshifts.opt.stderr
+++ b/tests/ui/lint/lint-exceeding-bitshifts.opt.stderr
@@ -10,143 +10,5 @@ note: the lint level is defined here
LL | #![warn(arithmetic_overflow)]
| ^^^^^^^^^^^^^^^^^^^
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:22:13
- |
-LL | let _ = x << 42;
- | ^^^^^^^ attempt to shift left by `42_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:27:15
- |
-LL | let n = 1u8 << 8;
- | ^^^^^^^^ attempt to shift left by `8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:29:15
- |
-LL | let n = 1u16 << 16;
- | ^^^^^^^^^^ attempt to shift left by `16_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:31:15
- |
-LL | let n = 1u32 << 32;
- | ^^^^^^^^^^ attempt to shift left by `32_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:33:15
- |
-LL | let n = 1u64 << 64;
- | ^^^^^^^^^^ attempt to shift left by `64_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:35:15
- |
-LL | let n = 1i8 << 8;
- | ^^^^^^^^ attempt to shift left by `8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:37:15
- |
-LL | let n = 1i16 << 16;
- | ^^^^^^^^^^ attempt to shift left by `16_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:39:15
- |
-LL | let n = 1i32 << 32;
- | ^^^^^^^^^^ attempt to shift left by `32_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:41:15
- |
-LL | let n = 1i64 << 64;
- | ^^^^^^^^^^ attempt to shift left by `64_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:44:15
- |
-LL | let n = 1u8 >> 8;
- | ^^^^^^^^ attempt to shift right by `8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:46:15
- |
-LL | let n = 1u16 >> 16;
- | ^^^^^^^^^^ attempt to shift right by `16_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:48:15
- |
-LL | let n = 1u32 >> 32;
- | ^^^^^^^^^^ attempt to shift right by `32_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:50:15
- |
-LL | let n = 1u64 >> 64;
- | ^^^^^^^^^^ attempt to shift right by `64_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:52:15
- |
-LL | let n = 1i8 >> 8;
- | ^^^^^^^^ attempt to shift right by `8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:54:15
- |
-LL | let n = 1i16 >> 16;
- | ^^^^^^^^^^ attempt to shift right by `16_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:56:15
- |
-LL | let n = 1i32 >> 32;
- | ^^^^^^^^^^ attempt to shift right by `32_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:58:15
- |
-LL | let n = 1i64 >> 64;
- | ^^^^^^^^^^ attempt to shift right by `64_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:62:15
- |
-LL | let n = n << 8;
- | ^^^^^^ attempt to shift left by `8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:64:15
- |
-LL | let n = 1u8 << -8;
- | ^^^^^^^^^ attempt to shift left by `-8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:69:15
- |
-LL | let n = 1u8 << (4+4);
- | ^^^^^^^^^^^^ attempt to shift left by `8_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:71:15
- |
-LL | let n = 1i64 >> [64][0];
- | ^^^^^^^^^^^^^^^ attempt to shift right by `64_i32`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:77:15
- |
-LL | let n = 1_isize << BITS;
- | ^^^^^^^^^^^^^^^ attempt to shift left by `%BITS%`, which would overflow
-
-warning: this arithmetic operation will overflow
- --> $DIR/lint-exceeding-bitshifts.rs:78:15
- |
-LL | let n = 1_usize << BITS;
- | ^^^^^^^^^^^^^^^ attempt to shift left by `%BITS%`, which would overflow
-
-warning: 24 warnings emitted
+warning: 1 warning emitted