AMDGPU: Custom lower v2f16 fneg/fabs with illegal f16
Fixes terrible code on targets without f16 support. The
legalization creates a mess that is difficult to recover
from. Also should avoid randomly breaking these tests
multiple times in sequence in future commits.
Some regressions in cases where it happens to be better
to pull the source modifier after the conversion.
llvm-svn: 334132
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index d95cdcb..6df499c 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -531,6 +531,9 @@
// Legalization hack.
setOperationAction(ISD::SELECT, MVT::v2i16, Custom);
setOperationAction(ISD::SELECT, MVT::v2f16, Custom);
+
+ setOperationAction(ISD::FNEG, MVT::v2f16, Custom);
+ setOperationAction(ISD::FABS, MVT::v2f16, Custom);
}
for (MVT VT : { MVT::v4i16, MVT::v4f16, MVT::v2i8, MVT::v4i8, MVT::v8i8 }) {
@@ -3700,6 +3703,28 @@
Results.push_back(DAG.getNode(ISD::BITCAST, SL, VT, NewSelect));
return;
}
+ case ISD::FNEG: {
+ SDLoc SL(N);
+ assert(N->getValueType(0) == MVT::v2f16);
+ SDValue BC = DAG.getNode(ISD::BITCAST, SL, MVT::i32, N->getOperand(0));
+
+ SDValue Op = DAG.getNode(ISD::XOR, SL, MVT::i32,
+ BC,
+ DAG.getConstant(0x80008000, SL, MVT::i32));
+ Results.push_back(DAG.getNode(ISD::BITCAST, SL, MVT::v2f16, Op));
+ return;
+ }
+ case ISD::FABS: {
+ SDLoc SL(N);
+ assert(N->getValueType(0) == MVT::v2f16);
+ SDValue BC = DAG.getNode(ISD::BITCAST, SL, MVT::i32, N->getOperand(0));
+
+ SDValue Op = DAG.getNode(ISD::AND, SL, MVT::i32,
+ BC,
+ DAG.getConstant(0x7fff7fff, SL, MVT::i32));
+ Results.push_back(DAG.getNode(ISD::BITCAST, SL, MVT::v2f16, Op));
+ return;
+ }
default:
break;
}