[PATCH] D69339: [SelectionDAG] Add support for FP_ROUND in WidenVectorOperand.

[Jay Foad via Phabricator via llvm-commits]

foad created this revision.
Herald added subscribers: hiraditya, tpr, nhaehnle, jvesely.
Herald added a project: LLVM.

This is used on AMDGPU for rounding from v3f64 (which is illegal) to
v3f32 (which is legal).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D69339

Files:
  llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
  llvm/test/CodeGen/AMDGPU/fptrunc.ll


Index: llvm/test/CodeGen/AMDGPU/fptrunc.ll
===================================================================
--- llvm/test/CodeGen/AMDGPU/fptrunc.ll
+++ llvm/test/CodeGen/AMDGPU/fptrunc.ll
@@ -30,6 +30,16 @@
   ret void
 }
 
+; FUNC-LABEL: {{^}}fptrunc_v3f64_to_v3f32:
+; GCN: v_cvt_f32_f64_e32
+; GCN: v_cvt_f32_f64_e32
+; GCN: v_cvt_f32_f64_e32
+define amdgpu_kernel void @fptrunc_v3f64_to_v3f32(<3 x float> addrspace(1)* %out, <3 x double> %in) {
+  %result = fptrunc <3 x double> %in to <3 x float>
+  store <3 x float> %result, <3 x float> addrspace(1)* %out
+  ret void
+}
+
 ; FUNC-LABEL: {{^}}fptrunc_v4f64_to_v4f32:
 ; GCN: v_cvt_f32_f64_e32
 ; GCN: v_cvt_f32_f64_e32
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -4161,6 +4161,8 @@
 
   case ISD::FP_EXTEND:
   case ISD::STRICT_FP_EXTEND:
+  case ISD::FP_ROUND:
+  case ISD::STRICT_FP_ROUND:
   case ISD::FP_TO_SINT:
   case ISD::STRICT_FP_TO_SINT:
   case ISD::FP_TO_UINT:
@@ -4297,13 +4299,21 @@
   if (TLI.isTypeLegal(WideVT) && !N->isStrictFPOpcode()) {
     SDValue Res;
     if (N->isStrictFPOpcode()) {
-      Res = DAG.getNode(Opcode, dl, { WideVT, MVT::Other }, 
-                        { N->getOperand(0), InOp });
+      if (Opcode == ISD::STRICT_FP_ROUND)
+        Res = DAG.getNode(Opcode, dl, { WideVT, MVT::Other },
+                          { N->getOperand(0), InOp, N->getOperand(2) });
+      else
+        Res = DAG.getNode(Opcode, dl, { WideVT, MVT::Other },
+                          { N->getOperand(0), InOp });
       // Legalize the chain result - switch anything that used the old chain to
       // use the new one.
       ReplaceValueWith(SDValue(N, 1), Res.getValue(1));
-    } else
-      Res = DAG.getNode(Opcode, dl, WideVT, InOp);
+    } else {
+      if (Opcode == ISD::FP_ROUND)
+        Res = DAG.getNode(Opcode, dl, WideVT, InOp, N->getOperand(1));
+      else
+        Res = DAG.getNode(Opcode, dl, WideVT, InOp);
+    }
     return DAG.getNode(
         ISD::EXTRACT_SUBVECTOR, dl, VT, Res,
         DAG.getConstant(0, dl, TLI.getVectorIdxTy(DAG.getDataLayout())));


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