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Don't validate constants before propagation

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Validation is neither necessary nor desirable.

The validation is already omitted at mir-opt-level >= 3, so there there
are not changes in MIR test output (the propagation of invalid constants
is covered by an existing test in tests/mir-opt/const_prop/invalid_constant.rs).
This commit is contained in:
Tomasz Miąsko 2023-03-14 00:00:00 +00:00
parent 9c044d77a3
commit 6a8fcdc597
1 changed files with 3 additions and 15 deletions
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18
compiler/rustc_mir_transform/src/const_prop.rs
View File

@ -22,9 +22,9 @@
use crate::MirPass;
use rustc_const_eval::interpret::{
self, compile_time_machine, AllocId, ConstAllocation, ConstValue, CtfeValidationMode, Frame,
ImmTy, Immediate, InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, PlaceTy, Pointer,
Scalar, StackPopCleanup,
self, compile_time_machine, AllocId, ConstAllocation, ConstValue, Frame, ImmTy, Immediate,
InterpCx, InterpResult, LocalValue, MemoryKind, OpTy, PlaceTy, Pointer, Scalar,
StackPopCleanup,
};
/// The maximum number of bytes that we'll allocate space for a local or the return value.
@ -628,18 +628,6 @@ fn replace_with_const(&mut self, place: Place<'tcx>, rval: &mut Rvalue<'tcx>) {
}
trace!("attempting to replace {:?} with {:?}", rval, value);
if let Err(e) = self.ecx.const_validate_operand(
value,
vec![],
// FIXME: is ref tracking too expensive?
// FIXME: what is the point of ref tracking if we do not even check the tracked refs?
&mut interpret::RefTracking::empty(),
CtfeValidationMode::Regular,
) {
trace!("validation error, attempt failed: {:?}", e);
return;
}
// FIXME> figure out what to do when read_immediate_raw fails
let imm = self.ecx.read_immediate_raw(value).ok();