Reapply r143177 and r143179 (reverting r143188), with scheduler

fixes: Use a separate register, instead of SP, as the
calling-convention resource, to avoid spurious conflicts with
actual uses of SP. Also, fix unscheduling of calling sequences,
which can be triggered by pseudo-two-address dependencies.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143206 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 16 insertions, 0 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 07d2db63fa..010a740dc7 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -5290,6 +5290,10 @@ void SelectionDAG::ReplaceAllUsesWith(SDValue FromN, SDValue To,
     // already exists there, recursively merge the results together.
     AddModifiedNodeToCSEMaps(User, &Listener);
   }
+
+  // If we just RAUW'd the root, take note.
+  if (FromN == getRoot())
+    setRoot(To);
 }
 
 /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
@@ -5335,6 +5339,10 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From, SDNode *To,
     // already exists there, recursively merge the results together.
     AddModifiedNodeToCSEMaps(User, &Listener);
   }
+
+  // If we just RAUW'd the root, take note.
+  if (From == getRoot().getNode())
+    setRoot(SDValue(To, getRoot().getResNo()));
 }
 
 /// ReplaceAllUsesWith - Modify anything using 'From' to use 'To' instead.
@@ -5373,6 +5381,10 @@ void SelectionDAG::ReplaceAllUsesWith(SDNode *From,
     // already exists there, recursively merge the results together.
     AddModifiedNodeToCSEMaps(User, &Listener);
   }
+
+  // If we just RAUW'd the root, take note.
+  if (From == getRoot().getNode())
+    setRoot(SDValue(To[getRoot().getResNo()]));
 }
 
 /// ReplaceAllUsesOfValueWith - Replace any uses of From with To, leaving
@@ -5431,6 +5443,10 @@ void SelectionDAG::ReplaceAllUsesOfValueWith(SDValue From, SDValue To,
     // already exists there, recursively merge the results together.
     AddModifiedNodeToCSEMaps(User, &Listener);
   }
+
+  // If we just RAUW'd the root, take note.
+  if (From == getRoot())
+    setRoot(To);
 }
 
 namespace {