[NVPTX] Make the legalizer expand shufflevector of <2 x half>

There's no direct instruction for this, but it's trivially implemented
with two movs. Without this the code generator just dies when
encountering a shufflevector.

Differential Revision: https://reviews.llvm.org/D46116

llvm-svn: 330948

2 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
index 5405e9dd001..527f0997e64 100644
--- a/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp
@@ -375,6 +375,7 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   setOperationAction(ISD::FP_TO_SINT, MVT::f16, Legal);
   setOperationAction(ISD::BUILD_VECTOR, MVT::v2f16, Custom);
   setOperationAction(ISD::EXTRACT_VECTOR_ELT, MVT::v2f16, Custom);
+  setOperationAction(ISD::VECTOR_SHUFFLE, MVT::v2f16, Expand);
 
   setFP16OperationAction(ISD::SETCC, MVT::f16, Legal, Promote);
   setFP16OperationAction(ISD::SETCC, MVT::v2f16, Legal, Expand);
diff --git a/llvm/test/CodeGen/NVPTX/f16x2-instructions.ll b/llvm/test/CodeGen/NVPTX/f16x2-instructions.ll
index 5dc796ada37..3d58cfa3595 100644
--- a/llvm/test/CodeGen/NVPTX/f16x2-instructions.ll
+++ b/llvm/test/CodeGen/NVPTX/f16x2-instructions.ll
@@ -1423,5 +1423,13 @@ define <2 x half> @test_fmuladd(<2 x half> %a, <2 x half> %b, <2 x half> %c) #0
   ret <2 x half> %r

 }

 

+; CHECK-LABEL: test_shufflevector(

+; CHECK: mov.b32 {%h1, %h2}, %hh1;

+; CHECK: mov.b32 %hh2, {%h2, %h1};

+define <2 x half> @test_shufflevector(<2 x half> %a) #0 {

+  %s = shufflevector <2 x half> %a, <2 x half> undef, <2 x i32> <i32 1, i32 0>

+  ret <2 x half> %s

+}

+

 attributes #0 = { nounwind }

 attributes #1 = { "unsafe-fp-math" = "true" }