[AArch64] Add fallback in FastISel fp16 conversions

Summary:
- Fix assertion failures on F16 to/from int types in FastISel by falling
  back to regular ISel
- Add a testcase of various conversion cases with FastISel (-O0)

Reviewers: kristof.beyls, jmolloy, SjoerdMeijer

Reviewed By: SjoerdMeijer

Subscribers: SjoerdMeijer, llvm-commits, srhines, pirama, aemerson, rengolin, javed.absar, kristof.beyls

Differential Revision: https://reviews.llvm.org/D33734

llvm-svn: 305127

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Target/AArch64/AArch64FastISel.cpp b/llvm/lib/Target/AArch64/AArch64FastISel.cpp
index 9ac7ecb9cdb..e8fcf1a0e9b 100644
--- a/llvm/lib/Target/AArch64/AArch64FastISel.cpp
+++ b/llvm/lib/Target/AArch64/AArch64FastISel.cpp
@@ -2827,7 +2827,7 @@ bool AArch64FastISel::selectFPToInt(const Instruction *I, bool Signed) {
     return false;
 
   EVT SrcVT = TLI.getValueType(DL, I->getOperand(0)->getType(), true);
-  if (SrcVT == MVT::f128)
+  if (SrcVT == MVT::f128 || SrcVT == MVT::f16)
     return false;
 
   unsigned Opc;
@@ -2854,6 +2854,10 @@ bool AArch64FastISel::selectIntToFP(const Instruction *I, bool Signed) {
   MVT DestVT;
   if (!isTypeLegal(I->getType(), DestVT) || DestVT.isVector())
     return false;
+  // Let regular ISEL handle FP16
+  if (DestVT == MVT::f16)
+    return false;
+
   assert((DestVT == MVT::f32 || DestVT == MVT::f64) &&
          "Unexpected value type.");