In D66013#1627633, @wmi wrote:

I suspect there is some problem caused by interaction of .cfi_remember_state/.cfi_restore_state and CFIInstrInserter pass.

Considering the allocMBB is in the middle of the function. The CFA register is rbp instead of rsp in the prev MBB of allocMBB. At the beginning of allocMBB, CFIInstrInserter will insert a def_cfa_register to change the CFA register to rsp, which matches the state of function entry. The def_cfa_register will be inserted at the beginning of allocMBB and will be remembered by cfi_remember_state. Then .cfi_restore_state will restore the beginning of next MBB of allocMBB to have rsp instead of rbp as the CFA register, which is wrong.

LGTM. Thanks.

Thanks for the review.

Looks good to me. Thanks!

Also, it would be nice to fix LangRef to clarify the interaction of non-integral pointers with a known bit-pattern.

Hello. Is there anything I can do for this to proceed? Thank you!

Thank you for the comment!

Thanks for the review!

I think the argument, as an SSA Value, should be immutable. But here, argument at fixed frame index is, in the IR level, a pointer argument with byval attribute. We don't modify the pointer. A function could modify the content of the memory that argument points to, just like a regular pointer argument. The only difference is that we know the pointer points to a fixed stack location.

Thank you for the review!

Thank you for the review!

Thanks for the review!

Thanks for the review!

Thanks for the review!

Thank you for the review!

Patch description: s/idea/ideal/.

LGTM. Thanks.

Thanks for the review.

Thank you for the review!