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const-prop: handle overflow_check consistently for all operators

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This commit is contained in:
Ralf Jung 2020-02-08 23:01:36 +01:00
parent 0633a0e380
commit c5709ff6b7
1 changed files with 10 additions and 15 deletions
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25
src/librustc_mir/transform/const_prop.rs
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@ -541,7 +541,6 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
right: &Operand<'tcx>,
source_info: SourceInfo,
place_layout: TyLayout<'tcx>,
overflow_check: bool,
) -> Option<()> {
let r =
self.use_ecx(|this| this.ecx.read_immediate(this.ecx.eval_operand(right, None)?))?;
@ -564,18 +563,14 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
}
}
// If overflow checking is enabled (like in debug mode by default),
// then we'll already catch overflow when we evaluate the `Assert` statement
// in MIR. However, if overflow checking is disabled, then there won't be any
// `Assert` statement and so we have to do additional checking here.
if !overflow_check {
if self.use_ecx(|this| {
let l = this.ecx.read_immediate(this.ecx.eval_operand(left, None)?)?;
let (_res, overflow, _ty) = this.ecx.overflowing_binary_op(op, l, r)?;
Ok(overflow)
})? {
self.report_panic_as_lint(source_info, PanicInfo::Overflow(op))?;
}
// The remaining operators are handled through `overflowing_binary_op`.
// FIXME: Why do we not also do this for `Shr` and `Shl`?
if self.use_ecx(|this| {
let l = this.ecx.read_immediate(this.ecx.eval_operand(left, None)?)?;
let (_res, overflow, _ty) = this.ecx.overflowing_binary_op(op, l, r)?;
Ok(overflow)
})? {
self.report_panic_as_lint(source_info, PanicInfo::Overflow(op))?;
}
Some(())
@ -618,9 +613,9 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
// Additional checking: check for overflows on integer binary operations and report
// them to the user as lints.
Rvalue::BinaryOp(op, left, right) => {
Rvalue::BinaryOp(op, left, right) if !overflow_check => {
trace!("checking BinaryOp(op = {:?}, left = {:?}, right = {:?})", op, left, right);
self.check_binary_op(*op, left, right, source_info, place_layout, overflow_check)?;
self.check_binary_op(*op, left, right, source_info, place_layout)?;
}
// Do not try creating references (#67862)