stuij marked 9 inline comments as done. stuij added inline comments.
================ Comment at: clang/lib/Basic/Targets/AArch64.cpp:74 + BFloat16Width = BFloat16Align = 16; + BFloat16Format = &llvm::APFloat::BFloat(); + ---------------- SjoerdMeijer wrote: > stuij wrote: > > SjoerdMeijer wrote: > > > Nit: we use bfloat16 everywhere, would `llvm::APFloat::BFloat16()` be > > > better for consistency? > > In the IR world bfloat is consistently called bfloat, without the 16. I > > think this might turn into bikeshedding to justify if either one or both > > sides of the divide should or should not include the '16'. I can think of > > arguments to support the various options. > > > > As I think there's no clear winner, I'd like to take the route of less > > effort and keep things as is. > ah, I couldn't remember on which patch I commented on the bfloat16 vs bfloat > naming. > Since everything is called bfloat16, from the architecture extension to the > source language type, I find this a bit of a missed opportunity to get the > names consistent. And I wouldn't say that naming of types is bikeshedding. > But maybe that's just me... In general naming isn't bikeshedding. And I appreciate discussions on naming. I'm just afraid it might turn into bikeshedding. I do agree that such a remark isn't a very constructive to a conversation. Sorry. ================ Comment at: clang/test/CodeGen/arm-bf16-params-returns.c:5 +// RUN: %clang_cc1 -triple aarch64-arm-none-eabi -target-abi aapcs -mfloat-abi softfp -target-feature +bf16 -target-feature +neon -emit-llvm -O2 -o - %s | opt -S -mem2reg -sroa | FileCheck %s --check-prefix=CHECK64-SOFTFP + +// function return types ---------------- SjoerdMeijer wrote: > what happens with `-mfloat-abi=soft`. Does that deserve a test? Yes, this one is interesting. I think we shouldn't support bfloat at all in combination with -mfloat-abi=soft. We don't support software emulation of bfloat instructions and all operations on bfloat are simd instructions. It turns out cc1 will accept -mfloat-abi=soft with neon intrinsics, which will happily churn out neon instructions. This doesn't sound very soft. The driver will ignore -mfloat-abi=soft in certain combinations of cmdline instructions, but I haven't delved deep enough to know what's what. GCC doesn't allow soft+neon combination. Unfortunately it will actually crash for just a bfloat type by itself, which is quite useless without intrinsics. The Arm GCC folks will raise a ticket on this with as proposed solution to not allow this combination. As this issue seems bigger than just bfloat, and potentially there's driver code involved as well I thought it'd make sense to handle this in a separate patch. ================ Comment at: clang/test/CodeGen/arm-mangle-16bit-float.cpp:4 + +// CHECK64: define {{.*}}void @_Z3foou6__bf16(half %b) +// CHECK32: define {{.*}}void @_Z3foou6__bf16(i32 %b.coerce) ---------------- SjoerdMeijer wrote: > LukeGeeson wrote: > > SjoerdMeijer wrote: > > > LukeGeeson wrote: > > > > craig.topper wrote: > > > > > How can bfloat16 be passed as half? Don't they have a different > > > > > format? > > > > see the above comment about soft-abis > > > Probably I am bit confused too now... are the three possible types that > > > we are expecing not bfloat, i32, or i16? > > Hi Sjoerd, Good spot here I forgot to add a default case somewhere, which > > means AArch32 didn't observe `-mfloat-abi softfp` by default - and hence > > used bfloat where i32 was expected. > > > > I have a local patch for this and will send to Ties to merge into this one > > :) > > > > > > We're not sure what you mean by i16 however? > Ah, as I said, got confused. Now I see we use i16 for targets that don't > support bfloat16. So we probably need a test for that. As I wrote above, I think we currently should not allow it as long as there are no targets that support bfloat and have use for this combination. ================ Comment at: clang/test/CodeGen/arm-mangle-bf16.cpp:3 +// RUN: %clang_cc1 -triple arm-arm-none-eabi -target-feature +bf16 -mfloat-abi hard -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK32-HARD +// RUN: %clang_cc1 -triple arm-arm-none-eabi -target-feature +bf16 -mfloat-abi softfp -emit-llvm -o - %s | FileCheck %s --check-prefix=CHECK32-SOFTFP + ---------------- SjoerdMeijer wrote: > SjoerdMeijer wrote: > > nit: if the name mangling is Independent of the float ABI, then you might > > as well one runline and the abi option. > -> ... then you might as well have only one runline and remove the abi > option. yes, I thought it's better to be defensive here, in case the implementation changes. Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D76077/new/ https://reviews.llvm.org/D76077 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits