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HIR ConstEval - Add unchecked shift intrinsics
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@thepowersgang
thepowersgang committed Jan 4, 2024
1 parent f201b9f commit d4e2b70
Showing 1 changed file with 61 additions and 40 deletions.
101 changes: 61 additions & 40 deletions src/hir_conv/constant_evaluation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1499,9 +1499,52 @@ namespace {
const ::MIR::Param& val_r
)
{
bool did_overflow = false;
const auto& state = local_state.state;
auto ti = TypeInfo::for_type(ty);
const auto& state = local_state.state;
bool did_overflow = false;

// NOTE: Shifts can use any integer as the RHS, so give them special handling
if(op == ::MIR::eBinOp::BIT_SHL || op == ::MIR::eBinOp::BIT_SHR )
{
::HIR::TypeRef tmp_r;
const auto& ty_r = local_state.state.get_param_type(tmp_r, val_r);
auto ti_r = TypeInfo::for_type(ty_r);

auto r = ti_r.ty == TypeInfo::Unsigned
? local_state.read_param_uint(ti_r.bits, val_r)
: local_state.read_param_sint(ti_r.bits, val_r).get_inner();
auto amt = r.truncate_u64();
if( amt > ti.bits ) {
DEBUG("Shift out of range - " << r << " > " << ti.bits);
did_overflow = true;
amt = 0;
}
switch(ti.ty)
{
case TypeInfo::Unsigned: {
auto l = local_state.read_param_uint(ti.bits, val_l);
switch(op)
{
case ::MIR::eBinOp::BIT_SHL: dst.write_uint(state, ti.bits, ti.mask(l << amt)); break;
case ::MIR::eBinOp::BIT_SHR: dst.write_uint(state, ti.bits, ti.mask(l >> amt)); break;
default: MIR_BUG(state, "This block should only be active for SHL/SHR");
}
break; }
case TypeInfo::Signed: {
auto l = local_state.read_param_sint(ti.bits, val_l);
switch(op)
{
case ::MIR::eBinOp::BIT_SHL: dst.write_uint(state, ti.bits, ti.mask(l << amt)); break;
case ::MIR::eBinOp::BIT_SHR: dst.write_uint(state, ti.bits, ti.mask(l >> amt)); break;
default: MIR_BUG(state, "This block should only be active for SHL/SHR");
}
break; }
default:
MIR_BUG(state, "Invalid use of BIT_SHL/BIT_SHR on " << ty);
}
return did_overflow;
}

switch(ti.ty)
{
case TypeInfo::Float: {
Expand Down Expand Up @@ -1874,44 +1917,6 @@ namespace HIR {
::HIR::TypeRef tmp;
const auto& ty_l = state.get_param_type(tmp, e.val_l);
auto ti = TypeInfo::for_type(ty_l);
// NOTE: Shifts can use any integer as the RHS, so give them special handling
if(e.op == ::MIR::eBinOp::BIT_SHL || e.op == ::MIR::eBinOp::BIT_SHR )
{
::HIR::TypeRef tmp_r;
const auto& ty_r = state.get_param_type(tmp_r, e.val_r);
auto ti_r = TypeInfo::for_type(ty_r);

auto r = ti_r.ty == TypeInfo::Unsigned
? local_state.read_param_uint(ti_r.bits, e.val_r)
: local_state.read_param_sint(ti_r.bits, e.val_r).get_inner();
MIR_ASSERT(state, r <= ti.bits, "Shift out of range - " << r << " > " << ti.bits);
auto amt = r.truncate_u64();
switch(ti.ty)
{
case TypeInfo::Unsigned: {
auto l = local_state.read_param_uint(ti.bits, e.val_l);
switch(e.op)
{
case ::MIR::eBinOp::BIT_SHL: dst.write_uint(state, ti.bits, ti.mask(l << amt)); break;
case ::MIR::eBinOp::BIT_SHR: dst.write_uint(state, ti.bits, ti.mask(l >> amt)); break;
default: MIR_BUG(state, "This block should only be active for SHL/SHR");
}
break; }
case TypeInfo::Signed: {
auto l = local_state.read_param_sint(ti.bits, e.val_l);
switch(e.op)
{
case ::MIR::eBinOp::BIT_SHL: dst.write_uint(state, ti.bits, ti.mask(l << amt)); break;
case ::MIR::eBinOp::BIT_SHR: dst.write_uint(state, ti.bits, ti.mask(l >> amt)); break;
default: MIR_BUG(state, "This block should only be active for SHL/SHR");
}
break; }
default:
MIR_BUG(state, "Invalid use of BIT_SHL/BIT_SHR on " << ty_l);
}
// Skip the rest of this arm (breaks both loops in `TU_ARMA`)
break ;
}
bool did_overflow = do_arith_checked(local_state, ty_l, dst, e.val_l, e.op, e.val_r);
switch(e.op)
{
Expand All @@ -1921,6 +1926,12 @@ namespace HIR {
MIR_BUG(state, "Division/modulo by zero!");
}
break;
case ::MIR::eBinOp::BIT_SHL:
case ::MIR::eBinOp::BIT_SHR:
if(did_overflow) {
MIR_BUG(state, "Bit shift out of range");
}
break;
default:
break;
}
Expand Down Expand Up @@ -2373,6 +2384,16 @@ namespace HIR {
MIR_ASSERT(state, ty.data().is_Primitive(), "`" << te->name << "` with non-primitive " << ty);
do_arith_checked(local_state, ty, dst, e.args.at(0), ::MIR::eBinOp::SUB, e.args.at(1));
}
else if( te->name == "unchecked_shl" ) {
auto ty = ms.monomorph_type(state.sp, te->params.m_types.at(0));
MIR_ASSERT(state, ty.data().is_Primitive(), "`" << te->name << "` with non-primitive " << ty);
do_arith_checked(local_state, ty, dst, e.args.at(0), ::MIR::eBinOp::BIT_SHL, e.args.at(1));
}
else if( te->name == "unchecked_shr" ) {
auto ty = ms.monomorph_type(state.sp, te->params.m_types.at(0));
MIR_ASSERT(state, ty.data().is_Primitive(), "`" << te->name << "` with non-primitive " << ty);
do_arith_checked(local_state, ty, dst, e.args.at(0), ::MIR::eBinOp::BIT_SHR, e.args.at(1));
}
// - Except for div/rem, which add checking just in case
else if( te->name == "unchecked_rem" ) {
auto ty = ms.monomorph_type(state.sp, te->params.m_types.at(0));
Expand Down

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