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| author | Dylan DPC <dylan.dpc@gmail.com> | 2020-05-16 02:37:28 +0200 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-05-16 02:37:28 +0200 |
| commit | 941dfb954526432d2e55dfd1fdc9d2d8e933c89a (patch) | |
| tree | 63cca56d85a374171a51ccaf65d9d7a95a4b22d9 /src | |
| parent | 89866ce2c7e860c9c3acf5820c8839d2c4926c0a (diff) | |
| parent | e84b379351577cae8cc3e89bf66c71bcabf547d7 (diff) | |
| download | rust-941dfb954526432d2e55dfd1fdc9d2d8e933c89a.tar.gz rust-941dfb954526432d2e55dfd1fdc9d2d8e933c89a.zip | |
Rollup merge of #72220 - wesleywiser:const_prop_eval_consts, r=oli-obk
[const-prop] Don't replace Rvalues that are already constants This cleans up a few mir-opt tests which have slight changes to spans for `consts` as a result of replacing them with new Rvalues.
Diffstat (limited to 'src')
5 files changed, 11 insertions, 6 deletions
diff --git a/src/librustc_mir/transform/const_prop.rs b/src/librustc_mir/transform/const_prop.rs index e898f22ec23..bdf2193c6af 100644 --- a/src/librustc_mir/transform/const_prop.rs +++ b/src/librustc_mir/transform/const_prop.rs @@ -616,6 +616,13 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> { value: OpTy<'tcx>, source_info: SourceInfo, ) { + if let Rvalue::Use(Operand::Constant(c)) = rval { + if !matches!(c.literal.val, ConstKind::Unevaluated(..)) { + trace!("skipping replace of Rvalue::Use({:?} because it is already a const", c); + return; + } + } + trace!("attepting to replace {:?} with {:?}", rval, value); if let Err(e) = self.ecx.const_validate_operand( value, diff --git a/src/test/mir-opt/const_prop/mutable_variable/rustc.main.ConstProp.diff b/src/test/mir-opt/const_prop/mutable_variable/rustc.main.ConstProp.diff index c6c5b0cf726..187c1745435 100644 --- a/src/test/mir-opt/const_prop/mutable_variable/rustc.main.ConstProp.diff +++ b/src/test/mir-opt/const_prop/mutable_variable/rustc.main.ConstProp.diff @@ -26,8 +26,7 @@ // + ty: i32 // + val: Value(Scalar(0x00000063)) // mir::Constant -- // + span: $DIR/mutable_variable.rs:6:9: 6:11 -+ // + span: $DIR/mutable_variable.rs:6:5: 6:11 + // + span: $DIR/mutable_variable.rs:6:9: 6:11 // + literal: Const { ty: i32, val: Value(Scalar(0x00000063)) } StorageLive(_2); // scope 1 at $DIR/mutable_variable.rs:7:9: 7:10 - _2 = _1; // scope 1 at $DIR/mutable_variable.rs:7:13: 7:14 diff --git a/src/test/mir-opt/const_prop/mutable_variable_aggregate/rustc.main.ConstProp.diff b/src/test/mir-opt/const_prop/mutable_variable_aggregate/rustc.main.ConstProp.diff index 26f0250d94c..cf432b2acc1 100644 --- a/src/test/mir-opt/const_prop/mutable_variable_aggregate/rustc.main.ConstProp.diff +++ b/src/test/mir-opt/const_prop/mutable_variable_aggregate/rustc.main.ConstProp.diff @@ -34,8 +34,7 @@ // + ty: i32 // + val: Value(Scalar(0x00000063)) // mir::Constant -- // + span: $DIR/mutable_variable_aggregate.rs:6:11: 6:13 -+ // + span: $DIR/mutable_variable_aggregate.rs:6:5: 6:13 + // + span: $DIR/mutable_variable_aggregate.rs:6:11: 6:13 // + literal: Const { ty: i32, val: Value(Scalar(0x00000063)) } StorageLive(_2); // scope 1 at $DIR/mutable_variable_aggregate.rs:7:9: 7:10 - _2 = _1; // scope 1 at $DIR/mutable_variable_aggregate.rs:7:13: 7:14 diff --git a/src/test/mir-opt/copy_propagation_arg/rustc.arg_src.CopyPropagation.diff b/src/test/mir-opt/copy_propagation_arg/rustc.arg_src.CopyPropagation.diff index b976449ca6d..1e0271a560f 100644 --- a/src/test/mir-opt/copy_propagation_arg/rustc.arg_src.CopyPropagation.diff +++ b/src/test/mir-opt/copy_propagation_arg/rustc.arg_src.CopyPropagation.diff @@ -17,7 +17,7 @@ // + ty: i32 // + val: Value(Scalar(0x0000007b)) // mir::Constant - // + span: $DIR/copy_propagation_arg.rs:29:5: 29:12 + // + span: $DIR/copy_propagation_arg.rs:29:9: 29:12 // + literal: Const { ty: i32, val: Value(Scalar(0x0000007b)) } _0 = _2; // scope 1 at $DIR/copy_propagation_arg.rs:30:5: 30:6 StorageDead(_2); // scope 0 at $DIR/copy_propagation_arg.rs:31:1: 31:2 diff --git a/src/test/mir-opt/copy_propagation_arg/rustc.bar.CopyPropagation.diff b/src/test/mir-opt/copy_propagation_arg/rustc.bar.CopyPropagation.diff index 26f8068f674..b875bbea67b 100644 --- a/src/test/mir-opt/copy_propagation_arg/rustc.bar.CopyPropagation.diff +++ b/src/test/mir-opt/copy_propagation_arg/rustc.bar.CopyPropagation.diff @@ -28,7 +28,7 @@ // + ty: u8 // + val: Value(Scalar(0x05)) // mir::Constant - // + span: $DIR/copy_propagation_arg.rs:17:5: 17:10 + // + span: $DIR/copy_propagation_arg.rs:17:9: 17:10 // + literal: Const { ty: u8, val: Value(Scalar(0x05)) } _0 = const (); // scope 0 at $DIR/copy_propagation_arg.rs:15:19: 18:2 // ty::Const |