Merge of r51073-51074 from use-diet branch.

Do not rely on std::swap<Use>, provide a (faster) member function instead.
This change is primarily necessitated by MSVC++'s incompatibility with
declaring std::swap<Use> to be a friend of Use.

Also contains some minor tweaks to Use inline functions,
to undo pointless changes that sneaked in with the last merge.

llvm-svn: 51078

1 files changed, 29 insertions, 0 deletions

diff --git a/llvm/lib/VMCore/Use.cpp b/llvm/lib/VMCore/Use.cpp
index a510d1a41ce..0672209bffa 100644
--- a/llvm/lib/VMCore/Use.cpp
+++ b/llvm/lib/VMCore/Use.cpp
@@ -16,6 +16,35 @@
 namespace llvm {
 
 //===----------------------------------------------------------------------===//
+//                         Use swap Implementation
+//===----------------------------------------------------------------------===//
+
+void Use::swap(Use &RHS) {
+  Value *V1(Val);
+  Value *V2(RHS.Val);
+  if (V1 != V2) {
+    if (V1) {
+      removeFromList();
+    }
+
+    if (V2) {
+      RHS.removeFromList();
+      Val = V2;
+      V2->addUse(*this);
+    } else {
+      Val = 0;
+    }
+
+    if (V1) {
+      RHS.Val = V1;
+      V1->addUse(RHS);
+    } else {
+      RHS.Val = 0;
+    }
+  }
+}
+
+//===----------------------------------------------------------------------===//
 //                         Use getImpliedUser Implementation
 //===----------------------------------------------------------------------===//