diff options
Diffstat (limited to 'compiler/rustc_mir_transform/src/gvn.rs')
| -rw-r--r-- | compiler/rustc_mir_transform/src/gvn.rs | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/compiler/rustc_mir_transform/src/gvn.rs b/compiler/rustc_mir_transform/src/gvn.rs index 3052369c3ca..699b218d46d 100644 --- a/compiler/rustc_mir_transform/src/gvn.rs +++ b/compiler/rustc_mir_transform/src/gvn.rs @@ -817,6 +817,9 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } Rvalue::UnaryOp(op, ref mut arg) => { let arg = self.simplify_operand(arg, location)?; + if let Some(value) = self.simplify_unary(op, arg) { + return Some(value); + } Value::UnaryOp(op, arg) } Rvalue::Discriminant(ref mut place) => { @@ -917,6 +920,23 @@ impl<'body, 'tcx> VnState<'body, 'tcx> { } #[instrument(level = "trace", skip(self), ret)] + fn simplify_unary(&mut self, op: UnOp, value: VnIndex) -> Option<VnIndex> { + let value = match (op, self.get(value)) { + (UnOp::Not, Value::UnaryOp(UnOp::Not, inner)) => return Some(*inner), + (UnOp::Neg, Value::UnaryOp(UnOp::Neg, inner)) => return Some(*inner), + (UnOp::Not, Value::BinaryOp(BinOp::Eq, lhs, rhs)) => { + Value::BinaryOp(BinOp::Ne, *lhs, *rhs) + } + (UnOp::Not, Value::BinaryOp(BinOp::Ne, lhs, rhs)) => { + Value::BinaryOp(BinOp::Eq, *lhs, *rhs) + } + _ => return None, + }; + + Some(self.insert(value)) + } + + #[instrument(level = "trace", skip(self), ret)] fn simplify_binary( &mut self, op: BinOp, |