shader/arithmetic_integer: Change IAdd to UAdd to avoid signed overflow

Signed integer addition overflow might be undefined behavior. It's free
to change operations to UAdd and use unsigned integers to avoid
potential bugs.
This commit is contained in:
ReinUsesLisp 2020-04-25 22:42:33 -03:00
parent c788f9c0bd
commit 2a96bea6a7

View File

@ -40,12 +40,12 @@ u32 ShaderIR::DecodeArithmeticInteger(NodeBlock& bb, u32 pc) {
op_a = GetOperandAbsNegInteger(op_a, false, instr.alu_integer.negate_a, true); op_a = GetOperandAbsNegInteger(op_a, false, instr.alu_integer.negate_a, true);
op_b = GetOperandAbsNegInteger(op_b, false, instr.alu_integer.negate_b, true); op_b = GetOperandAbsNegInteger(op_b, false, instr.alu_integer.negate_b, true);
Node value = Operation(OperationCode::IAdd, op_a, op_b); Node value = Operation(OperationCode::UAdd, op_a, op_b);
if (instr.iadd.x) { if (instr.iadd.x) {
Node carry = GetInternalFlag(InternalFlag::Carry); Node carry = GetInternalFlag(InternalFlag::Carry);
Node x = Operation(OperationCode::Select, std::move(carry), Immediate(1), Immediate(0)); Node x = Operation(OperationCode::Select, std::move(carry), Immediate(1), Immediate(0));
value = Operation(OperationCode::IAdd, std::move(value), std::move(x)); value = Operation(OperationCode::UAdd, std::move(value), std::move(x));
} }
if (instr.generates_cc) { if (instr.generates_cc) {