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Auto merge of #51594 - eddyb:issue-51582, r=nagisa

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rustc_codegen_llvm: don't treat i1 as signed, even for #[repr(i8)] enums.

Fixes #51582. r? @nagisa cc @nox @oli-obk
This commit is contained in:
bors 2018-06-16 21:48:31 +00:00
commit ae46aefd5b
3 changed files with 37 additions and 2 deletions
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6
src/librustc_codegen_llvm/mir/place.rs
View file

@ -275,7 +275,11 @@ impl<'a, 'tcx> PlaceRef<'tcx> {
layout::Variants::Single { .. } => bug!(),
layout::Variants::Tagged { ref tag, .. } => {
let signed = match tag.value {
layout::Int(_, signed) => signed,
// We use `i1` for bytes that are always `0` or `1`,
// e.g. `#[repr(i8)] enum E { A, B }`, but we can't
// let LLVM interpret the `i1` as signed, because
// then `i1 1` (i.e. E::B) is effectively `i8 -1`.
layout::Int(_, signed) => !tag.is_bool() && signed,
_ => false
};
bx.intcast(lldiscr, cast_to, signed)

6
src/librustc_codegen_llvm/mir/rvalue.rs
View file

@ -298,7 +298,11 @@ impl<'a, 'tcx> FunctionCx<'a, 'tcx> {
let mut signed = false;
if let layout::Abi::Scalar(ref scalar) = operand.layout.abi {
if let layout::Int(_, s) = scalar.value {
signed = s;
// We use `i1` for bytes that are always `0` or `1`,
// e.g. `#[repr(i8)] enum E { A, B }`, but we can't
// let LLVM interpret the `i1` as signed, because
// then `i1 1` (i.e. E::B) is effectively `i8 -1`.
signed = !scalar.is_bool() && s;
if scalar.valid_range.end() > scalar.valid_range.start() {
// We want `table[e as usize]` to not