Make sure the selector emits register register copies with flag operands

linking them to calls when appropriate, this prevents the scheduler from
pulling these copies away from the call.

This fixes Ptrdist/yacr2

llvm-svn: 23143

1 files changed, 20 insertions, 10 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
index f2d65697da7..06f363601a4 100644
--- a/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelDAGToDAG.cpp
@@ -1512,6 +1512,8 @@ SDOperand PPC32DAGToDAGISel::Select(SDOperand Op) {
       PPC::F8, PPC::F9, PPC::F10, PPC::F11, PPC::F12, PPC::F13
     };
     
+    SDOperand InFlag;  // Null incoming flag value.
+    
     for (unsigned i = 2, e = N->getNumOperands(); i != e; ++i) {
       unsigned DestReg = 0;
       MVT::ValueType RegTy;
@@ -1528,17 +1530,21 @@ SDOperand PPC32DAGToDAGISel::Select(SDOperand Op) {
       }
 
       if (N->getOperand(i).getOpcode() != ISD::UNDEF) {
-        SDOperand Reg = CurDAG->getRegister(DestReg, RegTy);
-        Chain = CurDAG->getNode(ISD::CopyToReg, MVT::Other, Chain, Reg,
-                                Select(N->getOperand(i)));
-        CallOperands.push_back(Reg);
+        Chain = CurDAG->getCopyToReg(Chain, DestReg,
+                                     Select(N->getOperand(i)), InFlag);
+        InFlag = Chain.getValue(1);
+        CallOperands.push_back(CurDAG->getRegister(DestReg, RegTy));
       }
     }
 
     // Finally, once everything is in registers to pass to the call, emit the
     // call itself.
-    CallOperands.push_back(Chain);
-    Chain = CurDAG->getTargetNode(CallOpcode, MVT::Other, CallOperands);
+    if (InFlag.Val)
+      CallOperands.push_back(InFlag);   // Strong dep on register copies.
+    else
+      CallOperands.push_back(Chain);    // Weak dep on whatever occurs before
+    Chain = CurDAG->getTargetNode(CallOpcode, MVT::Other, MVT::Flag,
+                                  CallOperands);
     
     std::vector<SDOperand> CallResults;
     
@@ -1548,18 +1554,22 @@ SDOperand PPC32DAGToDAGISel::Select(SDOperand Op) {
     case MVT::Other: break;
     case MVT::i32:
       if (N->getValueType(1) == MVT::i32) {
-        Chain = CurDAG->getCopyFromReg(Chain, PPC::R4, MVT::i32).getValue(1);
+        Chain = CurDAG->getCopyFromReg(Chain, PPC::R4, MVT::i32, 
+                                       Chain.getValue(1)).getValue(1);
         CallResults.push_back(Chain.getValue(0));
-        Chain = CurDAG->getCopyFromReg(Chain, PPC::R3, MVT::i32).getValue(1);
+        Chain = CurDAG->getCopyFromReg(Chain, PPC::R3, MVT::i32,
+                                       Chain.getValue(1)).getValue(1);
         CallResults.push_back(Chain.getValue(0));
       } else {
-        Chain = CurDAG->getCopyFromReg(Chain, PPC::R3, MVT::i32).getValue(1);
+        Chain = CurDAG->getCopyFromReg(Chain, PPC::R3, MVT::i32,
+                                       Chain.getValue(1)).getValue(1);
         CallResults.push_back(Chain.getValue(0));
       }
       break;
     case MVT::f32:
     case MVT::f64:
-      Chain = CurDAG->getCopyFromReg(Chain, PPC::F1, MVT::f64).getValue(1);
+      Chain = CurDAG->getCopyFromReg(Chain, PPC::F1, MVT::f64,
+                                     Chain.getValue(1)).getValue(1);
       if (N->getValueType(0) == MVT::f64)
         CallResults.push_back(Chain.getValue(0));
       else