Initial implementation of MipsTargetLowering::isLegalAddressingMode.

llvm-svn: 168230

2 files changed, 22 insertions, 0 deletions

diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index e225b6c28eb..6202ae9a30c 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -3483,6 +3483,26 @@ void MipsTargetLowering::LowerAsmOperandForConstraint(SDValue Op,
 }
 
 bool
+MipsTargetLowering::isLegalAddressingMode(const AddrMode &AM, Type *Ty) const {
+  // No global is ever allowed as a base.
+  if (AM.BaseGV)
+    return false;
+
+  switch (AM.Scale) {
+  case 0: // "r+i" or just "i", depending on HasBaseReg.
+    break;
+  case 1:
+    if (!AM.HasBaseReg) // allow "r+i".
+      break;
+    return false; // disallow "r+r" or "r+r+i".
+  default:
+    return false;
+  }
+
+  return true;
+}
+
+bool
 MipsTargetLowering::isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const {
   // The Mips target isn't yet aware of offsets.
   return false;
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.h b/llvm/lib/Target/Mips/MipsISelLowering.h
index 43f97e89a7b..2c17def06a1 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.h
+++ b/llvm/lib/Target/Mips/MipsISelLowering.h
@@ -357,6 +357,8 @@ namespace llvm {
                                               std::vector<SDValue> &Ops,
                                               SelectionDAG &DAG) const;
 
+    virtual bool isLegalAddressingMode(const AddrMode &AM, Type *Ty) const;
+
     virtual bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const;
 
     virtual EVT getOptimalMemOpType(uint64_t Size, unsigned DstAlign,