PtrAdd would complicate Structure Analysis and data layout optimizations.
To add to what efriedma-quic was already discussing!!!
The opaque pointers have already complicated Structure Analysis and data layout optimizations. Opaque pointers has removed the (Luxurious) high level constructs (with typeinfo) in IR and is making it closer to low level or machine code. Typed pointers to more extent was making pointer types explicit and ‘bitcast’ instructions were providing a ease picture of type cast or using objects in different (in disciplined) typed mode.
‘Geps’ are abstract and disciplined ways of accessing structures, these definitely helps in Structure Analysis and data layout optimizations. ‘Geps’ currently even in Opaque world are providing type information ‘getSourceElementType()’, analysis would get further complicated without this minimal information.
Pointer types of structure fields, function prototypes with exact pointer type, global variables with exact pointer types, ‘bitcast’ instructions, alloca pointer types, etc (a) —were all assets earlier in typed world. Now in the opaque world figuring out (a) would require lots of analysis effort and compile time. These issues complicate the Structure analysis.
Further removal of ‘Geps’ which accesses the first field of a structure as mentioned in
complicates the analysis.
Lastly this feature of PtrAdd would make the structure analysis further complicated with no type information and the discipline/abstraction of GEP.