[PATCH] D82443: [ARM] Narrowing half-precision lowering to supported CCs

[Puyan Lotfi via Phabricator via llvm-commits]

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In D82443#2111882 <https://reviews.llvm.org/D82443#2111882>, @pratlucas wrote:

> It seems most of the argument lowering convertions get simplifyed on the regular case, when not using `fastcc`.
>  When using it, though, type legalization ends up trying to handle a `i16 = bitcast ConstantFP:f16<APFloat(0)>` node, turning it into an `i32 <- f32` operation and getting lost while trying to create the new constant.
>
> Avoiding the splitting should do the trick for `fastcc`, as it has no need to conform with AAPCS. I'm not sure about `swiftcc`, though, as it is expected to comply with AAPCS-VFP on ios platforms according to LLVM's language reference manual.






================
Comment at: llvm/lib/Target/ARM/ARMISelLowering.cpp:4159
+    IsABIRegCopy =
+        (CCVal == CallingConv::ARM_APCS || CCVal == CallingConv::ARM_AAPCS);
+  }
----------------
pratlucas wrote:
> `CallingConv::ARM_AAPCS_VFP` and `CallingConv::C` would also need to be included here.
I believe I tried ARM_AAPCS_VFP and it asserted. Lemme confirm. 


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https://reviews.llvm.org/D82443