[PATCH] D67128: [X86] Move x86_64 fp128 conversion to libcalls from type legalization to DAG legalization

[Craig Topper via Phabricator via llvm-commits]

craig.topper marked an inline comment as done.
craig.topper added inline comments.


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Comment at: llvm/lib/Target/X86/X86ISelLowering.cpp:666
+                                                   : &X86::VR128RegClass);
+    setOperationAction(ISD::FADD, MVT::f128, Custom);
+    setOperationAction(ISD::FSUB, MVT::f128, Custom);
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I suspect we can use Expand here and let LegalizeDAG form libcalls for FADD/FSUB/FMUL/FDIV, but what I have here is what AArch64 does. I think LegalizeDAG didn't handle those operations for libcalls at the time the AArch64 code was written. I went conservative for X86 here because LegalizeDAG can form tail calls to the library which legalize types didn't do and my custom handler doesn't either. This avoided some test divergences.


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  https://reviews.llvm.org/D67128/new/

https://reviews.llvm.org/D67128