diff options
| -rw-r--r-- | compiler/rustc_mir_transform/src/instcombine.rs | 79 | ||||
| -rw-r--r-- | tests/mir-opt/intrinsic_asserts.generic.InstCombine.diff | 42 | ||||
| -rw-r--r-- | tests/mir-opt/intrinsic_asserts.panics.InstCombine.diff | 47 | ||||
| -rw-r--r-- | tests/mir-opt/intrinsic_asserts.removable.InstCombine.diff | 45 | ||||
| -rw-r--r-- | tests/mir-opt/intrinsic_asserts.rs | 28 |
5 files changed, 239 insertions, 2 deletions
diff --git a/compiler/rustc_mir_transform/src/instcombine.rs b/compiler/rustc_mir_transform/src/instcombine.rs index 2f3c65869ef..1b795479a92 100644 --- a/compiler/rustc_mir_transform/src/instcombine.rs +++ b/compiler/rustc_mir_transform/src/instcombine.rs @@ -6,7 +6,8 @@ use rustc_middle::mir::{ BinOp, Body, Constant, ConstantKind, LocalDecls, Operand, Place, ProjectionElem, Rvalue, SourceInfo, Statement, StatementKind, Terminator, TerminatorKind, UnOp, }; -use rustc_middle::ty::{self, TyCtxt}; +use rustc_middle::ty::{self, layout::TyAndLayout, ParamEnv, SubstsRef, Ty, TyCtxt}; +use rustc_span::symbol::{sym, Symbol}; pub struct InstCombine; @@ -16,7 +17,11 @@ impl<'tcx> MirPass<'tcx> for InstCombine { } fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) { - let ctx = InstCombineContext { tcx, local_decls: &body.local_decls }; + let ctx = InstCombineContext { + tcx, + local_decls: &body.local_decls, + param_env: tcx.param_env_reveal_all_normalized(body.source.def_id()), + }; for block in body.basic_blocks.as_mut() { for statement in block.statements.iter_mut() { match statement.kind { @@ -33,6 +38,10 @@ impl<'tcx> MirPass<'tcx> for InstCombine { &mut block.terminator.as_mut().unwrap(), &mut block.statements, ); + ctx.combine_intrinsic_assert( + &mut block.terminator.as_mut().unwrap(), + &mut block.statements, + ); } } } @@ -40,6 +49,7 @@ impl<'tcx> MirPass<'tcx> for InstCombine { struct InstCombineContext<'tcx, 'a> { tcx: TyCtxt<'tcx>, local_decls: &'a LocalDecls<'tcx>, + param_env: ParamEnv<'tcx>, } impl<'tcx> InstCombineContext<'tcx, '_> { @@ -200,4 +210,69 @@ impl<'tcx> InstCombineContext<'tcx, '_> { }); terminator.kind = TerminatorKind::Goto { target: destination_block }; } + + fn combine_intrinsic_assert( + &self, + terminator: &mut Terminator<'tcx>, + _statements: &mut Vec<Statement<'tcx>>, + ) { + let TerminatorKind::Call { func, target, .. } = &mut terminator.kind else { return; }; + let Some(target_block) = target else { return; }; + let func_ty = func.ty(self.local_decls, self.tcx); + let Some((intrinsic_name, substs)) = resolve_rust_intrinsic(self.tcx, func_ty) else { + return; + }; + // The intrinsics we are interested in have one generic parameter + if substs.is_empty() { + return; + } + let ty = substs.type_at(0); + + // Check this is a foldable intrinsic before we query the layout of our generic parameter + let Some(assert_panics) = intrinsic_assert_panics(intrinsic_name) else { return; }; + let Ok(layout) = self.tcx.layout_of(self.param_env.and(ty)) else { return; }; + if assert_panics(self.tcx, layout) { + // If we know the assert panics, indicate to later opts that the call diverges + *target = None; + } else { + // If we know the assert does not panic, turn the call into a Goto + terminator.kind = TerminatorKind::Goto { target: *target_block }; + } + } +} + +fn intrinsic_assert_panics<'tcx>( + intrinsic_name: Symbol, +) -> Option<fn(TyCtxt<'tcx>, TyAndLayout<'tcx>) -> bool> { + fn inhabited_predicate<'tcx>(_tcx: TyCtxt<'tcx>, layout: TyAndLayout<'tcx>) -> bool { + layout.abi.is_uninhabited() + } + fn zero_valid_predicate<'tcx>(tcx: TyCtxt<'tcx>, layout: TyAndLayout<'tcx>) -> bool { + !tcx.permits_zero_init(layout) + } + fn mem_uninitialized_valid_predicate<'tcx>( + tcx: TyCtxt<'tcx>, + layout: TyAndLayout<'tcx>, + ) -> bool { + !tcx.permits_uninit_init(layout) + } + + match intrinsic_name { + sym::assert_inhabited => Some(inhabited_predicate), + sym::assert_zero_valid => Some(zero_valid_predicate), + sym::assert_mem_uninitialized_valid => Some(mem_uninitialized_valid_predicate), + _ => None, + } +} + +fn resolve_rust_intrinsic<'tcx>( + tcx: TyCtxt<'tcx>, + func_ty: Ty<'tcx>, +) -> Option<(Symbol, SubstsRef<'tcx>)> { + if let ty::FnDef(def_id, substs) = *func_ty.kind() { + if tcx.is_intrinsic(def_id) { + return Some((tcx.item_name(def_id), substs)); + } + } + None } diff --git a/tests/mir-opt/intrinsic_asserts.generic.InstCombine.diff b/tests/mir-opt/intrinsic_asserts.generic.InstCombine.diff new file mode 100644 index 00000000000..8ff64c1ea15 --- /dev/null +++ b/tests/mir-opt/intrinsic_asserts.generic.InstCombine.diff @@ -0,0 +1,42 @@ +- // MIR for `generic` before InstCombine ++ // MIR for `generic` after InstCombine + + fn generic() -> () { + let mut _0: (); // return place in scope 0 at $DIR/intrinsic_asserts.rs:+0:21: +0:21 + let _1: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:46 + let _2: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:47 + let _3: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:60 + + bb0: { + StorageLive(_1); // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:46 + _1 = assert_inhabited::<T>() -> bb1; // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:46 + // mir::Constant + // + span: $DIR/intrinsic_asserts.rs:25:5: 25:44 + // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_inhabited::<T>}, val: Value(<ZST>) } + } + + bb1: { + StorageDead(_1); // scope 0 at $DIR/intrinsic_asserts.rs:+1:46: +1:47 + StorageLive(_2); // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:47 + _2 = assert_zero_valid::<T>() -> bb2; // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:47 + // mir::Constant + // + span: $DIR/intrinsic_asserts.rs:26:5: 26:45 + // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_zero_valid::<T>}, val: Value(<ZST>) } + } + + bb2: { + StorageDead(_2); // scope 0 at $DIR/intrinsic_asserts.rs:+2:47: +2:48 + StorageLive(_3); // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:60 + _3 = assert_mem_uninitialized_valid::<T>() -> bb3; // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:60 + // mir::Constant + // + span: $DIR/intrinsic_asserts.rs:27:5: 27:58 + // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_mem_uninitialized_valid::<T>}, val: Value(<ZST>) } + } + + bb3: { + StorageDead(_3); // scope 0 at $DIR/intrinsic_asserts.rs:+3:60: +3:61 + nop; // scope 0 at $DIR/intrinsic_asserts.rs:+0:21: +4:2 + return; // scope 0 at $DIR/intrinsic_asserts.rs:+4:2: +4:2 + } + } + diff --git a/tests/mir-opt/intrinsic_asserts.panics.InstCombine.diff b/tests/mir-opt/intrinsic_asserts.panics.InstCombine.diff new file mode 100644 index 00000000000..ddc01590315 --- /dev/null +++ b/tests/mir-opt/intrinsic_asserts.panics.InstCombine.diff @@ -0,0 +1,47 @@ +- // MIR for `panics` before InstCombine ++ // MIR for `panics` after InstCombine + + fn panics() -> () { + let mut _0: (); // return place in scope 0 at $DIR/intrinsic_asserts.rs:+0:17: +0:17 + let _1: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:50 + let _2: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:49 + let _3: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:62 + + bb0: { + StorageLive(_1); // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:50 +- _1 = assert_inhabited::<Never>() -> bb1; // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:50 ++ _1 = assert_inhabited::<Never>(); // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:50 + // mir::Constant + // + span: $DIR/intrinsic_asserts.rs:17:5: 17:48 + // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_inhabited::<Never>}, val: Value(<ZST>) } + } + + bb1: { + StorageDead(_1); // scope 0 at $DIR/intrinsic_asserts.rs:+1:50: +1:51 + StorageLive(_2); // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:49 +- _2 = assert_zero_valid::<&u8>() -> bb2; // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:49 ++ _2 = assert_zero_valid::<&u8>(); // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:49 + // mir::Constant + // + span: $DIR/intrinsic_asserts.rs:18:5: 18:47 + // + user_ty: UserType(0) + // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_zero_valid::<&u8>}, val: Value(<ZST>) } + } + + bb2: { + StorageDead(_2); // scope 0 at $DIR/intrinsic_asserts.rs:+2:49: +2:50 + StorageLive(_3); // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:62 +- _3 = assert_mem_uninitialized_valid::<&u8>() -> bb3; // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:62 ++ _3 = assert_mem_uninitialized_valid::<&u8>(); // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:62 + // mir::Constant + // + span: $DIR/intrinsic_asserts.rs:19:5: 19:60 + // + user_ty: UserType(1) + // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_mem_uninitialized_valid::<&u8>}, val: Value(<ZST>) } + } + + bb3: { + StorageDead(_3); // scope 0 at $DIR/intrinsic_asserts.rs:+3:62: +3:63 + nop; // scope 0 at $DIR/intrinsic_asserts.rs:+0:17: +4:2 + return; // scope 0 at $DIR/intrinsic_asserts.rs:+4:2: +4:2 + } + } + diff --git a/tests/mir-opt/intrinsic_asserts.removable.InstCombine.diff b/tests/mir-opt/intrinsic_asserts.removable.InstCombine.diff new file mode 100644 index 00000000000..568fbf1a0d6 --- /dev/null +++ b/tests/mir-opt/intrinsic_asserts.removable.InstCombine.diff @@ -0,0 +1,45 @@ +- // MIR for `removable` before InstCombine ++ // MIR for `removable` after InstCombine + + fn removable() -> () { + let mut _0: (); // return place in scope 0 at $DIR/intrinsic_asserts.rs:+0:20: +0:20 + let _1: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:47 + let _2: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:48 + let _3: (); // in scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:61 + + bb0: { + StorageLive(_1); // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:47 +- _1 = assert_inhabited::<()>() -> bb1; // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:47 +- // mir::Constant +- // + span: $DIR/intrinsic_asserts.rs:7:5: 7:45 +- // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_inhabited::<()>}, val: Value(<ZST>) } ++ goto -> bb1; // scope 0 at $DIR/intrinsic_asserts.rs:+1:5: +1:47 + } + + bb1: { + StorageDead(_1); // scope 0 at $DIR/intrinsic_asserts.rs:+1:47: +1:48 + StorageLive(_2); // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:48 +- _2 = assert_zero_valid::<u8>() -> bb2; // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:48 +- // mir::Constant +- // + span: $DIR/intrinsic_asserts.rs:8:5: 8:46 +- // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_zero_valid::<u8>}, val: Value(<ZST>) } ++ goto -> bb2; // scope 0 at $DIR/intrinsic_asserts.rs:+2:5: +2:48 + } + + bb2: { + StorageDead(_2); // scope 0 at $DIR/intrinsic_asserts.rs:+2:48: +2:49 + StorageLive(_3); // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:61 +- _3 = assert_mem_uninitialized_valid::<u8>() -> bb3; // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:61 +- // mir::Constant +- // + span: $DIR/intrinsic_asserts.rs:9:5: 9:59 +- // + literal: Const { ty: extern "rust-intrinsic" fn() {assert_mem_uninitialized_valid::<u8>}, val: Value(<ZST>) } ++ goto -> bb3; // scope 0 at $DIR/intrinsic_asserts.rs:+3:5: +3:61 + } + + bb3: { + StorageDead(_3); // scope 0 at $DIR/intrinsic_asserts.rs:+3:61: +3:62 + nop; // scope 0 at $DIR/intrinsic_asserts.rs:+0:20: +4:2 + return; // scope 0 at $DIR/intrinsic_asserts.rs:+4:2: +4:2 + } + } + diff --git a/tests/mir-opt/intrinsic_asserts.rs b/tests/mir-opt/intrinsic_asserts.rs new file mode 100644 index 00000000000..8fb99cdf6e0 --- /dev/null +++ b/tests/mir-opt/intrinsic_asserts.rs @@ -0,0 +1,28 @@ +#![crate_type = "lib"] +#![feature(core_intrinsics)] + +// All these assertions pass, so all the intrinsic calls should be deleted. +// EMIT_MIR intrinsic_asserts.removable.InstCombine.diff +pub fn removable() { + core::intrinsics::assert_inhabited::<()>(); + core::intrinsics::assert_zero_valid::<u8>(); + core::intrinsics::assert_mem_uninitialized_valid::<u8>(); +} + +enum Never {} + +// These assertions all diverge, so their target blocks should become None. +// EMIT_MIR intrinsic_asserts.panics.InstCombine.diff +pub fn panics() { + core::intrinsics::assert_inhabited::<Never>(); + core::intrinsics::assert_zero_valid::<&u8>(); + core::intrinsics::assert_mem_uninitialized_valid::<&u8>(); +} + +// Whether or not these asserts pass isn't known, so they shouldn't be modified. +// EMIT_MIR intrinsic_asserts.generic.InstCombine.diff +pub fn generic<T>() { + core::intrinsics::assert_inhabited::<T>(); + core::intrinsics::assert_zero_valid::<T>(); + core::intrinsics::assert_mem_uninitialized_valid::<T>(); +} |