Hi,

this work-in-progress patch implements a new option 
-foffload-alias=<none|pointer|all>.


The option -foffload-alias=none instructs the compiler to assume that
objects references and pointer dereferences in an offload region do not 
alias.

The option -foffload-alias=pointer instructs the compiler to assume that 
objects references in an offload region do not alias.

The option -foffload-alias=all instructs the compiler to make no 
assumptions about aliasing in offload regions.

The default value is -foffload-alias=none.


The patch works by adding restrict to the types of the fields used to 
pass data to an offloading region.

Atm, the kernels-loop-offload-alias-ptr.c test-case passes, but the 
kernels-loop-offload-alias-none.c test-case fails.  For the latter, the 
required amount of restrict is added, but it has no effect. I've 
reported this in a more basic form in PR67742: "3rd-level restrict ignored".

Thanks,
- Tom