mirror of https://github.com/rust-lang/rust.git
InstCombine away intrinsic validity assertions
This commit is contained in:
Ben Kimock
parent
b8f9cb345a
commit
662199f125
|
|
@ -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
|
||||
}
|
||||
|
|
|
|||
|
|
@ -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
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -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
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -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
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -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>();
|
||||
}
|
||||
Loading…
Reference in New Issue