[CIR][CIRGen] wip - Convert trivial copy constructor and assignment operator calls to memcpy

[shubhe25p]

Issue #1202: Added a test file, lifetime check fails with an unexpected remark

Run command:
clang -cc1 -std=c++20 -triple x86_64-unknown-linux-gnu -mconstructor-aliases -fclangir -fclangir-lifetime-check="history=all;remarks=all" -clangir-verify-diagnostics -emit-cir trivial.cpp

The following error is encountered:

trivial.cpp:1:8: error: unexpected remark: pset => { fn_arg:0 }
struct Trivial{ int i; };
       ^

Not sure what's wrong here? Any idea @bcardosolopes

[bcardosolopes]

There's nothing wrong there, if you look at CIR output in https://godbolt.org/z/7995W6dv9, this message is displayed for the trivial struct constructor _ZN7TrivialC2ERKS_, which is implicitly generated by the compiler, hence no much info by the message.

You are getting an error because -clangir-verify-diagnostics will turn any message into an error (this flag is only used when writing tests for the compiler). The remark is just a way to debug the lifetimecheck (enabled in -fclangir-lifetime-check="history=all;remarks=all"), and is basically saying that something is holding a pointer to the first constructor argument (which is true).

[shubhe25p]

You are getting an error because -clangir-verify-diagnostics will turn any message into an error (this flag is only used when writing tests for the compiler). The remark is just a way to debug the lifetimecheck (enabled in -fclangir-lifetime-check="history=all;remarks=all"), and is basically saying that something is holding a pointer to the first constructor argument (which is true).

Thanks it makes sense, now.

There's nothing wrong there, if you look at CIR output in https://godbolt.org/z/7995W6dv9, this message is displayed for the trivial struct constructor _ZN7TrivialC2ERKS_, which is implicitly generated by the compiler, hence no much info by the message.

I’m wondering why you mentioned doing a lifetime check on this in Discord, as there isn't much information provided. Is there a specific reason for it? What else could I explore? Apologies if the question seems basic.