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Auto merge of #105582 - saethlin:instcombine-assert-inhabited, r=cjgillot

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InstCombine away intrinsic validity assertions

This optimization (currently) fires 246 times on the standard library. It seems to fire hardly at all on the big crates in the benchmark suite. Interesting.
This commit is contained in:
bors 2023-01-26 03:10:52 +00:00
commit 885bf62887
12 changed files with 276 additions and 16 deletions
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4
compiler/rustc_const_eval/src/interpret/intrinsics.rs
View file

@ -447,7 +447,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
if intrinsic_name == sym::assert_zero_valid {
let should_panic = !self.tcx.permits_zero_init(layout);
let should_panic = !self.tcx.permits_zero_init(self.param_env.and(layout));
if should_panic {
M::abort(
@ -461,7 +461,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
}
if intrinsic_name == sym::assert_mem_uninitialized_valid {
let should_panic = !self.tcx.permits_uninit_init(layout);
let should_panic = !self.tcx.permits_uninit_init(self.param_env.and(layout));
if should_panic {
M::abort(

11
compiler/rustc_const_eval/src/lib.rs
View file

@ -58,7 +58,12 @@ pub fn provide(providers: &mut Providers) {
let (param_env, value) = param_env_and_value.into_parts();
const_eval::deref_mir_constant(tcx, param_env, value)
};
providers.permits_uninit_init =
|tcx, ty| util::might_permit_raw_init(tcx, ty, InitKind::UninitMitigated0x01Fill);
providers.permits_zero_init = |tcx, ty| util::might_permit_raw_init(tcx, ty, InitKind::Zero);
providers.permits_uninit_init = |tcx, param_env_and_ty| {
let (param_env, ty) = param_env_and_ty.into_parts();
util::might_permit_raw_init(tcx, param_env, ty, InitKind::UninitMitigated0x01Fill)
};
providers.permits_zero_init = |tcx, param_env_and_ty| {
let (param_env, ty) = param_env_and_ty.into_parts();
util::might_permit_raw_init(tcx, param_env, ty, InitKind::Zero)
};
}

3
compiler/rustc_const_eval/src/util/might_permit_raw_init.rs
View file

@ -20,13 +20,14 @@ use crate::interpret::{InterpCx, MemoryKind, OpTy};
/// to the full uninit check).
pub fn might_permit_raw_init<'tcx>(
tcx: TyCtxt<'tcx>,
param_env: ParamEnv<'tcx>,
ty: TyAndLayout<'tcx>,
kind: InitKind,
) -> bool {
if tcx.sess.opts.unstable_opts.strict_init_checks {
might_permit_raw_init_strict(ty, tcx, kind)
} else {
let layout_cx = LayoutCx { tcx, param_env: ParamEnv::reveal_all() };
let layout_cx = LayoutCx { tcx, param_env };
might_permit_raw_init_lax(ty, &layout_cx, kind)
}
}