[PATCH] D60762: [SelectionDAG] Legalize vaargs that require vector splitting

[Luke Lau via Phabricator via llvm-commits]

luke created this revision.
luke added reviewers: delena, bogner.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

This adds vector splitting for vaarg instructions during type legalization


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D60762

Files:
  llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
  llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
  llvm/test/CodeGen/X86/legalize-vaarg.ll


Index: llvm/test/CodeGen/X86/legalize-vaarg.ll
===================================================================
--- /dev/null
+++ llvm/test/CodeGen/X86/legalize-vaarg.ll
@@ -0,0 +1,11 @@
+;RUN: llc < %s -mtriple=x86_64-- -mattr=avx | FileCheck %s
+
+define <32 x i32> @test_large_vec_vaarg(i32 %n, ...) {
+  %args = alloca i8*, align 4
+;CHECK: vmovaps {{.*}} %ymm0
+;CHECK: vmovaps {{.*}} %ymm1
+;CHECK: vmovaps {{.*}} %ymm2
+;CHECK: vmovaps {{.*}} %ymm3
+  %x = va_arg i8** %args, <32 x i32>
+  ret <32 x i32> %x
+}
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -816,6 +816,9 @@
   case ISD::VECTOR_SHUFFLE:
     SplitVecRes_VECTOR_SHUFFLE(cast<ShuffleVectorSDNode>(N), Lo, Hi);
     break;
+  case ISD::VAARG:
+    SplitVecRes_VAARG(N, Lo, Hi);
+    break;
 
   case ISD::ANY_EXTEND_VECTOR_INREG:
   case ISD::SIGN_EXTEND_VECTOR_INREG:
@@ -1787,6 +1790,27 @@
   }
 }
 
+void DAGTypeLegalizer::SplitVecRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi) {
+  EVT OVT = N->getValueType(0);
+  EVT NVT = OVT.getHalfNumVectorElementsVT(*DAG.getContext());
+  SDValue Chain = N->getOperand(0);
+  SDValue Ptr = N->getOperand(1);
+  SDValue SV = N->getOperand(2);
+  SDLoc dl(N);
+  const unsigned Align = N->getConstantOperandVal(3);
+
+  Lo = DAG.getVAArg(NVT, dl, Chain, Ptr, SV, Align);
+  Hi = DAG.getVAArg(NVT, dl, Lo.getValue(1), Ptr, SV, 0);
+  Chain = Hi.getValue(1);
+
+  if (DAG.getDataLayout().isBigEndian())
+    std::swap(Lo, Hi);
+
+  // Modified the chain - switch anything that used the old chain to use
+  // the new one.
+  ReplaceValueWith(SDValue(N, 1), Chain);
+}
+
 
 //===----------------------------------------------------------------------===//
 //  Operand Vector Splitting
Index: llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
===================================================================
--- llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -755,6 +755,7 @@
   void SplitVecRes_SETCC(SDNode *N, SDValue &Lo, SDValue &Hi);
   void SplitVecRes_VECTOR_SHUFFLE(ShuffleVectorSDNode *N, SDValue &Lo,
                                   SDValue &Hi);
+  void SplitVecRes_VAARG(SDNode *N, SDValue &Lo, SDValue &Hi);
 
   // Vector Operand Splitting: <128 x ty> -> 2 x <64 x ty>.
   bool SplitVectorOperand(SDNode *N, unsigned OpNo);


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