[PATCH] D118420: [AArch64] Add isel for bitcasting between bfloat and half types.

[Paul Walker via Phabricator via llvm-commits]

paulwalker-arm created this revision.
Herald added subscribers: hiraditya, kristof.beyls.
paulwalker-arm requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D118420

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/lib/Target/AArch64/AArch64InstrInfo.td
  llvm/test/CodeGen/AArch64/bf16.ll


Index: llvm/test/CodeGen/AArch64/bf16.ll
===================================================================
--- llvm/test/CodeGen/AArch64/bf16.ll
+++ llvm/test/CodeGen/AArch64/bf16.ll
@@ -82,3 +82,17 @@
 
   ret { <8 x bfloat>, <8 x bfloat>* } %res
 }
+
+define bfloat @test_bitcast_halftobfloat(half %a) nounwind {
+; CHECK-LABEL: test_bitcast_halftobfloat:
+; CHECK-NEXT: ret
+  %r = bitcast half %a to bfloat
+  ret bfloat %r
+}
+
+define half @test_bitcast_bfloattohalf(bfloat %a) nounwind {
+; CHECK-LABEL: test_bitcast_bfloattohalf:
+; CHECK-NEXT: ret
+  %r = bitcast bfloat %a to half
+  ret half %r
+}
Index: llvm/lib/Target/AArch64/AArch64InstrInfo.td
===================================================================
--- llvm/lib/Target/AArch64/AArch64InstrInfo.td
+++ llvm/lib/Target/AArch64/AArch64InstrInfo.td
@@ -7550,6 +7550,9 @@
 def : Pat<(i64 (bitconvert (v1f64 V64:$Vn))),
           (COPY_TO_REGCLASS V64:$Vn, GPR64)>;
 
+def : Pat<(f16 (bitconvert (bf16 FPR16:$src))), (f16 FPR16:$src)>;
+def : Pat<(bf16 (bitconvert (f16 FPR16:$src))), (bf16 FPR16:$src)>;
+
 let Predicates = [IsLE] in {
 def : Pat<(v1i64 (bitconvert (v2i32 FPR64:$src))), (v1i64 FPR64:$src)>;
 def : Pat<(v1i64 (bitconvert (v4i16 FPR64:$src))), (v1i64 FPR64:$src)>;
Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -3746,6 +3746,10 @@
   if (OpVT != MVT::f16 && OpVT != MVT::bf16)
     return SDValue();
 
+  // Bitcasts between f16 and bf16 are legal.
+  if (ArgVT == MVT::f16 || ArgVT == MVT::bf16)
+    return Op;
+
   assert(ArgVT == MVT::i16);
   SDLoc DL(Op);
 


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