diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/librustc_mir/transform/match_branches.rs | 16 | ||||
| -rw-r--r-- | src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff | 64 |
2 files changed, 75 insertions, 5 deletions
diff --git a/src/librustc_mir/transform/match_branches.rs b/src/librustc_mir/transform/match_branches.rs index 07dec23429b..74da6d5e629 100644 --- a/src/librustc_mir/transform/match_branches.rs +++ b/src/librustc_mir/transform/match_branches.rs @@ -52,8 +52,11 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification { if let Some(f_c) = f_c.literal.try_eval_bool(tcx, param_env) { // This should also be a bool because it's writing to the same place let s_c = s_c.literal.try_eval_bool(tcx, param_env).unwrap(); - assert_ne!(f_c, s_c, "Unexpected match would've compared eq earlier"); - continue; + if f_c != s_c { + // have to check this here because f_c & s_c might have + // different spans. + continue; + } } continue 'outer; } @@ -63,9 +66,9 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification { } // Take owenership of items now that we know we can optimize. let discr = discr.clone(); + let (from, first) = bbs.pick2_mut(bb_idx, first); - bbs[bb_idx].terminator_mut().kind = TerminatorKind::Goto { target: first }; - for s in bbs[first].statements.iter_mut() { + let new_stmts = first.statements.iter().cloned().map(|mut s| { if let StatementKind::Assign(box (_, ref mut rhs)) = s.kind { if let Rvalue::Use(Operand::Constant(c)) = rhs { let size = tcx.layout_of(param_env.and(switch_ty)).unwrap().size; @@ -81,7 +84,10 @@ impl<'tcx> MirPass<'tcx> for MatchBranchSimplification { } } } - } + s + }); + from.statements.extend(new_stmts); + from.terminator_mut().kind = first.terminator().kind.clone(); } } } diff --git a/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff b/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff new file mode 100644 index 00000000000..b0a861f6c5e --- /dev/null +++ b/src/test/mir-opt/matches_reduce_branches.foo.MatchBranchSimplification.diff @@ -0,0 +1,64 @@ +- // MIR for `foo` before MatchBranchSimplification ++ // MIR for `foo` after MatchBranchSimplification + + fn foo(_1: std::option::Option<()>) -> () { + debug bar => _1; // in scope 0 at $DIR/matches_reduce_branches.rs:3:8: 3:11 + let mut _0: (); // return place in scope 0 at $DIR/matches_reduce_branches.rs:3:25: 3:25 + let mut _2: bool; // in scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL + let mut _3: isize; // in scope 0 at $DIR/matches_reduce_branches.rs:4:22: 4:26 + + bb0: { + StorageLive(_2); // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL + _3 = discriminant(_1); // scope 0 at $DIR/matches_reduce_branches.rs:4:22: 4:26 +- switchInt(move _3) -> [0_isize: bb2, otherwise: bb1]; // scope 0 at $DIR/matches_reduce_branches.rs:4:22: 4:26 ++ goto -> bb2; // scope 0 at $DIR/matches_reduce_branches.rs:4:22: 4:26 + } + + bb1: { + _2 = const false; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL + // ty::Const + // + ty: bool + // + val: Value(Scalar(0x00)) + // mir::Constant + // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL + // + literal: Const { ty: bool, val: Value(Scalar(0x00)) } + goto -> bb3; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL + } + + bb2: { +- _2 = const true; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL ++ _2 = Eq(move _3, const 0_isize); // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL + // ty::Const +- // + ty: bool +- // + val: Value(Scalar(0x01)) ++ // + ty: isize ++ // + val: Value(Scalar(0x0000000000000000)) + // mir::Constant +- // + span: $SRC_DIR/core/src/macros/mod.rs:LL:COL +- // + literal: Const { ty: bool, val: Value(Scalar(0x01)) } ++ // + span: $DIR/matches_reduce_branches.rs:1:1: 1:1 ++ // + literal: Const { ty: isize, val: Value(Scalar(0x0000000000000000)) } + goto -> bb3; // scope 0 at $SRC_DIR/core/src/macros/mod.rs:LL:COL + } + + bb3: { + switchInt(_2) -> [false: bb4, otherwise: bb5]; // scope 0 at $DIR/matches_reduce_branches.rs:4:5: 6:6 + } + + bb4: { + _0 = const (); // scope 0 at $DIR/matches_reduce_branches.rs:4:5: 6:6 + // ty::Const + // + ty: () + // + val: Value(Scalar(<ZST>)) + // mir::Constant + // + span: $DIR/matches_reduce_branches.rs:4:5: 6:6 + // + literal: Const { ty: (), val: Value(Scalar(<ZST>)) } + goto -> bb5; // scope 0 at $DIR/matches_reduce_branches.rs:4:5: 6:6 + } + + bb5: { + StorageDead(_2); // scope 0 at $DIR/matches_reduce_branches.rs:7:1: 7:2 + return; // scope 0 at $DIR/matches_reduce_branches.rs:7:2: 7:2 + } + } + |