[PATCH] D146408: [clang][Interp] Start supporting complex types

[Timm Bäder via Phabricator via cfe-commits]

tbaeder added inline comments.


================
Comment at: clang/lib/AST/Interp/PrimType.h:108
+    switch (Expr) {                                                            \
+      TYPE_SWITCH_CASE(PT_Sint8, B)                                            \
+      TYPE_SWITCH_CASE(PT_Uint8, B)                                            \
----------------
aaron.ballman wrote:
> tbaeder wrote:
> > aaron.ballman wrote:
> > > Oh boy, this is going to be interesting, isn't it?
> > > ```
> > > consteval _Complex _BitInt(12) UhOh() { return (_Complex _BitInt(12))1; }
> > > consteval _Complex _BitInt(18) Why() { return (_Complex _BitInt(18))1; }
> > > 
> > > static_assert(UhOh() + Why() == 2);
> > > ```
> > > 
> > `_BitInt` isn't supported in the new interpreter at all right now, so this just gets rejected.
> > 
> > 
> > Apart from that... is a complex bitint really something that should be supported? Not just in the new interpreter but generally?
> > _BitInt isn't supported in the new interpreter at all right now, so this just gets rejected.
> 
> Well, that's sort of good then! :-D We'll have to deal with `_BitInt` at some point, so maybe we can add this as a test case with expected failures and a fixit comment so we don't forget about it?
> 
> > Apart from that... is a complex bitint really something that should be supported? Not just in the new interpreter but generally?
> 
> I don't see why not; we support complex integer types and `_BitInt` is an integer type. We support `_Complex` from C in C++ and we support `_BitInt` from C in C++, so it seems reasonable to expect `_Complex _BitInt` to work.
> I don't see why not; we support complex integer types and _BitInt is an integer type. We support _Complex from C in C++ and we support _BitInt from C in C++, so it seems reasonable to expect _Complex _BitInt to work.

My immediate reaction to something like `_Complex` is "this is stupid, this belongs in user code". For floating-point values it at least makes sense from a mathematical POV I guess. But complex ints is already weird and complex arbitrary-width integers? What's the use case? `_Complex bool` is rejected as well after all.


================
Comment at: clang/lib/AST/Interp/PrimType.h:108
+    switch (Expr) {                                                            \
+      TYPE_SWITCH_CASE(PT_Sint8, B)                                            \
+      TYPE_SWITCH_CASE(PT_Uint8, B)                                            \
----------------
tbaeder wrote:
> aaron.ballman wrote:
> > tbaeder wrote:
> > > aaron.ballman wrote:
> > > > Oh boy, this is going to be interesting, isn't it?
> > > > ```
> > > > consteval _Complex _BitInt(12) UhOh() { return (_Complex _BitInt(12))1; }
> > > > consteval _Complex _BitInt(18) Why() { return (_Complex _BitInt(18))1; }
> > > > 
> > > > static_assert(UhOh() + Why() == 2);
> > > > ```
> > > > 
> > > `_BitInt` isn't supported in the new interpreter at all right now, so this just gets rejected.
> > > 
> > > 
> > > Apart from that... is a complex bitint really something that should be supported? Not just in the new interpreter but generally?
> > > _BitInt isn't supported in the new interpreter at all right now, so this just gets rejected.
> > 
> > Well, that's sort of good then! :-D We'll have to deal with `_BitInt` at some point, so maybe we can add this as a test case with expected failures and a fixit comment so we don't forget about it?
> > 
> > > Apart from that... is a complex bitint really something that should be supported? Not just in the new interpreter but generally?
> > 
> > I don't see why not; we support complex integer types and `_BitInt` is an integer type. We support `_Complex` from C in C++ and we support `_BitInt` from C in C++, so it seems reasonable to expect `_Complex _BitInt` to work.
> > I don't see why not; we support complex integer types and _BitInt is an integer type. We support _Complex from C in C++ and we support _BitInt from C in C++, so it seems reasonable to expect _Complex _BitInt to work.
> 
> My immediate reaction to something like `_Complex` is "this is stupid, this belongs in user code". For floating-point values it at least makes sense from a mathematical POV I guess. But complex ints is already weird and complex arbitrary-width integers? What's the use case? `_Complex bool` is rejected as well after all.
> We'll have to deal with _BitInt at some point, so maybe we can add this as a test case with expected failures and a fixit comment so we don't forget about it?

It's running into an assertion for the test case, so I added it commented-out.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D146408/new/

https://reviews.llvm.org/D146408