yaxunl added a comment. In D55067#1313290 <https://reviews.llvm.org/D55067#1313290>, @yaxunl wrote:
> In D55067#1313213 <https://reviews.llvm.org/D55067#1313213>, @rjmccall wrote: > > > This seems backwards. Clang knows what the actual ABI alignment of the C > > type is, and it doesn't have to match the alignment of the IR type that > > IRGen produces. It's the actual C ABI alignment that's supposed to affect > > the calling convention, so there needs to be some way to specify the C ABI > > alignment on the parameter in IR. That may mean using `byval`, which can > > be given an explicit alignment. > > > Also, the alignment of the kernel argument is only used to put the argument > in some buffer accessible to the device. It needs not match the C ABI > alignment. If the user take address of this argument, they will get address > of an alloca, which matches the C ABI alignment. > > For example, in code below, %s.coerce is OK to align to 1. If user takes its > address, they get %s, which is aligned to 8. > > %struct.S = type <{ i32*, i8, %struct.U, [5 x i8] }> > %struct.U = type { i16 } > > ; Function Attrs: convergent noinline nounwind optnone > define amdgpu_kernel void @_Z6kernelc1SPi(i8 %a, %struct.S %s.coerce, i32* > %b) #0 { > entry: > %s = alloca %struct.S, align 8, addrspace(5) > %s1 = addrspacecast %struct.S addrspace(5)* %s to %struct.S* > %a.addr = alloca i8, align 1, addrspace(5) > %0 = addrspacecast i8 addrspace(5)* %a.addr to i8* > %b.addr = alloca i32*, align 8, addrspace(5) > %1 = addrspacecast i32* addrspace(5)* %b.addr to i32** > store %struct.S %s.coerce, %struct.S* %s1, align 8 > store i8 %a, i8* %0, align 1 > store i32* %b, i32** %1, align 8 > ret void > } > > Well the bad thing is that users need to specify different offset for nvptx and amdgpu for the same kernel, if they ever calls {cuda|hip}SetupArgument explicitly. CHANGES SINCE LAST ACTION https://reviews.llvm.org/D55067/new/ https://reviews.llvm.org/D55067 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
