X86: change MOV64ri64i32 into MOV32ri64

The MOV64ri64i32 instruction required hacky MCInst lowering because it was
allocated as setting a GR64, but the eventual instruction ("movl") only set a
GR32. This converts it into a so-called "MOV32ri64" which still accepts a
(appropriate) 64-bit immediate but defines a GR32. This is then converted to
the full GR64 by a SUBREG_TO_REG operation, thus keeping everyone happy.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182991 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 0b6940ec71..02f5fe4952 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -200,6 +200,7 @@ namespace {
     bool SelectAddr(SDNode *Parent, SDValue N, SDValue &Base,
                     SDValue &Scale, SDValue &Index, SDValue &Disp,
                     SDValue &Segment);
+    bool SelectMOV64Imm32(SDValue N, SDValue &Imm);
     bool SelectLEAAddr(SDValue N, SDValue &Base,
                        SDValue &Scale, SDValue &Index, SDValue &Disp,
                        SDValue &Segment);
@@ -1380,6 +1381,33 @@ bool X86DAGToDAGISel::SelectScalarSSELoad(SDNode *Root,
 }
 
 
+bool X86DAGToDAGISel::SelectMOV64Imm32(SDValue N, SDValue &Imm) {
+  if (const ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N)) {
+    uint64_t ImmVal = CN->getZExtValue();
+    if ((uint32_t)ImmVal != (uint64_t)ImmVal)
+      return false;
+
+    Imm = CurDAG->getTargetConstant(ImmVal, MVT::i64);
+    return true;
+  }
+
+  // In static codegen with small code model, we can get the address of a label
+  // into a register with 'movl'. TableGen has already made sure we're looking
+  // at a label of some kind.
+  assert(N->getOpcode() == X86ISD::Wrapper && "Unexpected node type for MOV32ri64");
+  N = N.getOperand(0);
+
+  if (N->getOpcode() != ISD::TargetConstantPool &&
+      N->getOpcode() != ISD::TargetJumpTable &&
+      N->getOpcode() != ISD::TargetGlobalAddress &&
+      N->getOpcode() != ISD::TargetExternalSymbol &&
+      N->getOpcode() != ISD::TargetBlockAddress)
+    return false;
+
+  Imm = N;
+  return TM.getCodeModel() == CodeModel::Small;
+}
+
 /// SelectLEAAddr - it calls SelectAddr and determines if the maximal addressing
 /// mode it matches can be cost effectively emitted as an LEA instruction.
 bool X86DAGToDAGISel::SelectLEAAddr(SDValue N,