bjoernager/rust
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assume value ranges in transmute

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Fixes #109958
This commit is contained in:
Scott McMurray 2023-04-06 00:36:36 -07:00
parent d8fc819247
commit 1bcb0ec28c
4 changed files with 253 additions and 16 deletions
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63
compiler/rustc_codegen_ssa/src/mir/rvalue.rs
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@ -12,6 +12,7 @@ use rustc_middle::mir::Operand;
use rustc_middle::ty::cast::{CastTy, IntTy};
use rustc_middle::ty::layout::{HasTyCtxt, LayoutOf, TyAndLayout};
use rustc_middle::ty::{self, adjustment::PointerCast, Instance, Ty, TyCtxt};
use rustc_session::config::OptLevel;
use rustc_span::source_map::{Span, DUMMY_SP};
use rustc_target::abi::{self, FIRST_VARIANT};
@ -231,10 +232,16 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
(ScalarOrZst::Scalar(in_scalar), ScalarOrZst::Scalar(out_scalar))
if in_scalar.size(self.cx) == out_scalar.size(self.cx) =>
{
let operand_bty = bx.backend_type(operand.layout);
let cast_bty = bx.backend_type(cast);
Some(OperandValue::Immediate(
self.transmute_immediate(bx, imm, in_scalar, out_scalar, cast_bty),
))
Some(OperandValue::Immediate(self.transmute_immediate(
bx,
imm,
in_scalar,
operand_bty,
out_scalar,
cast_bty,
)))
}
_ => None,
}
@ -250,11 +257,13 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
&& in_a.size(self.cx) == out_a.size(self.cx)
&& in_b.size(self.cx) == out_b.size(self.cx)
{
let in_a_ibty = bx.scalar_pair_element_backend_type(operand.layout, 0, false);
let in_b_ibty = bx.scalar_pair_element_backend_type(operand.layout, 1, false);
let out_a_ibty = bx.scalar_pair_element_backend_type(cast, 0, false);
let out_b_ibty = bx.scalar_pair_element_backend_type(cast, 1, false);
Some(OperandValue::Pair(
self.transmute_immediate(bx, imm_a, in_a, out_a, out_a_ibty),
self.transmute_immediate(bx, imm_b, in_b, out_b, out_b_ibty),
self.transmute_immediate(bx, imm_a, in_a, in_a_ibty, out_a, out_a_ibty),
self.transmute_immediate(bx, imm_b, in_b, in_b_ibty, out_b, out_b_ibty),
))
} else {
None
@ -273,6 +282,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
bx: &mut Bx,
mut imm: Bx::Value,
from_scalar: abi::Scalar,
from_backend_ty: Bx::Type,
to_scalar: abi::Scalar,
to_backend_ty: Bx::Type,
) -> Bx::Value {
@ -280,6 +290,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
use abi::Primitive::*;
imm = bx.from_immediate(imm);
self.assume_scalar_range(bx, imm, from_scalar, from_backend_ty);
imm = match (from_scalar.primitive(), to_scalar.primitive()) {
(Int(..) | F32 | F64, Int(..) | F32 | F64) => bx.bitcast(imm, to_backend_ty),
(Pointer(..), Pointer(..)) => bx.pointercast(imm, to_backend_ty),
@ -294,10 +305,52 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
bx.bitcast(int_imm, to_backend_ty)
}
};
self.assume_scalar_range(bx, imm, to_scalar, to_backend_ty);
imm = bx.to_immediate_scalar(imm, to_scalar);
imm
}
fn assume_scalar_range(
&self,
bx: &mut Bx,
imm: Bx::Value,
scalar: abi::Scalar,
backend_ty: Bx::Type,
) {
if matches!(self.cx.sess().opts.optimize, OptLevel::No | OptLevel::Less)
|| !matches!(scalar.primitive(), abi::Primitive::Int(..))
|| scalar.is_always_valid(self.cx)
{
return;
}
let abi::WrappingRange { start, end } = scalar.valid_range(self.cx);
if start <= end {
if start > 0 {
let low = bx.const_uint_big(backend_ty, start);
let cmp = bx.icmp(IntPredicate::IntUGE, imm, low);
bx.assume(cmp);
}
let type_max = scalar.size(self.cx).unsigned_int_max();
if end < type_max {
let high = bx.const_uint_big(backend_ty, end);
let cmp = bx.icmp(IntPredicate::IntULE, imm, high);
bx.assume(cmp);
}
} else {
let low = bx.const_uint_big(backend_ty, start);
let cmp_low = bx.icmp(IntPredicate::IntUGE, imm, low);
let high = bx.const_uint_big(backend_ty, end);
let cmp_high = bx.icmp(IntPredicate::IntULE, imm, high);
let or = bx.or(cmp_low, cmp_high);
bx.assume(or);
}
}
pub fn codegen_rvalue_unsized(
&mut self,
bx: &mut Bx,