rjmccall added inline comments.
================
Comment at: clang/test/CodeGen/matrix-cast.c:15
+ // CHECK: [[C:%.*]] = load <25 x i8>, <25 x i8>* {{.*}}, align 1
+ // CHECK-NEXT: [[CONV:%.*]] = zext <25 x i8> [[C]] to <25 x i32>
+ // CHECK-NEXT: store <25 x i32> [[CONV]], <25 x i32>* {{.*}}, align 4
----------------
fhahn wrote:
> SaurabhJha wrote:
> > fhahn wrote:
> > > This doesn't seem right. We are casting between 2 signed types, so the
> > > sign should get preserved, right? Shouldn't this be `sext`? See
> > > https://godbolt.org/z/zWznYdnKW for the scalar case.
> > >
> > > I think you also need tests for casts with different bitwidths with
> > > unsigned, unsigned -> signed & signed -> unsigned.
> > This is happening because we are always passing inSigned argument to
> > `Builder.CreateIntCast` as false here
> > https://github.com/llvm/llvm-project/blob/main/clang/lib/CodeGen/CGExprScalar.cpp#L1348.
> > IfI change it to `true`, it generates `sext` instructions.
> >
> > I am figuring out how can I determine sign of src and dest type. Because
> > `SrcTy` and `DestTy` are vectors here, they are unsigned and `SrcElementTy`
> > and `DestElementTy` have no method like `isSignedIntegerOrEnumerationType`.
> > Once that's solved, this should be fixed.
> Oh right, I think I see what's going on. I think the code you are referring
> to is specifically for the vector types in Clang, but it is checking the LLVM
> type and we also use LLVM IR vector types for matrix values, so the code
> accidentally also covers matrix values at the moment.
>
> I *think* we should probably handled matrix values separately in this
> function. @rjmccall what do you think?
Yes, I would recommend that you recognize matrix values by their Clang type and
then call something in the matrix IR-generation library.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D99037/new/
https://reviews.llvm.org/D99037
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