fhahn 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
----------------
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?
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D99037/new/
https://reviews.llvm.org/D99037
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