bjoernager/rust
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Comment codegen optimization.

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This commit is contained in:
Camille GILLOT 2023-02-11 17:26:20 +00:00
parent 328696ca17
commit 4f13aa7f46
1 changed files with 3 additions and 0 deletions
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3
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
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@ -656,6 +656,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
// with #[rustc_inherit_overflow_checks] and inlined from // with #[rustc_inherit_overflow_checks] and inlined from
// another crate (mostly core::num generic/#[inline] fns), // another crate (mostly core::num generic/#[inline] fns),
// while the current crate doesn't use overflow checks. // while the current crate doesn't use overflow checks.
//
// As an optimization, we emit an unchecked binop when overflow checks are disabled,
// as the overflow flag would be ignored anyway.
if !bx.cx().check_overflow() { if !bx.cx().check_overflow() {
let val = self.codegen_scalar_binop(bx, op, lhs, rhs, input_ty); let val = self.codegen_scalar_binop(bx, op, lhs, rhs, input_ty);
return OperandValue::Pair(val, bx.cx().const_bool(false)); return OperandValue::Pair(val, bx.cx().const_bool(false));