Add support for ARM ldrexd/strexd intrinsics. They both use i32 register pairs
to load/store i64 values. Since there's no current support to explicitly
declare such restrictions, implement it by using specific hardcoded register
pairs during isel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132248 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMISelLowering.cpp b/lib/Target/ARM/ARMISelLowering.cpp
index f23d890..a78c3ed 100644
--- a/lib/Target/ARM/ARMISelLowering.cpp
+++ b/lib/Target/ARM/ARMISelLowering.cpp
@@ -7658,6 +7658,28 @@
     Info.writeMem = true;
     return true;
   }
+  case Intrinsic::arm_strexd: {
+    Info.opc = ISD::INTRINSIC_W_CHAIN;
+    Info.memVT = MVT::i64;
+    Info.ptrVal = I.getArgOperand(2);
+    Info.offset = 0;
+    Info.align = 8;
+    Info.vol = false;
+    Info.readMem = false;
+    Info.writeMem = true;
+    return true;
+  }
+  case Intrinsic::arm_ldrexd: {
+    Info.opc = ISD::INTRINSIC_W_CHAIN;
+    Info.memVT = MVT::i64;
+    Info.ptrVal = I.getArgOperand(0);
+    Info.offset = 0;
+    Info.align = 8;
+    Info.vol = false;
+    Info.readMem = true;
+    Info.writeMem = false;
+    return true;
+  }
   default:
     break;
   }