From d860aa62ac686b7a3b7c8978fee5c4ed3304fd01 Mon Sep 17 00:00:00 2001
From: Nate Begeman <natebegeman@mac.com>
Date: Mon, 4 Apr 2005 22:17:48 +0000
Subject: [PATCH] Make sure that arg regs used by the call instruction are
 marked as such, so that regalloc doesn't cleverly reuse early arg regs
 loading later arg regs. This fixes almost all outstanding failures in the
 pattern isel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21086 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PowerPC/PPCISelPattern.cpp | 40 +++++++++++++++++----------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/lib/Target/PowerPC/PPCISelPattern.cpp b/lib/Target/PowerPC/PPCISelPattern.cpp
index 8751f421f7f..dfd2d549252 100644
--- a/lib/Target/PowerPC/PPCISelPattern.cpp
+++ b/lib/Target/PowerPC/PPCISelPattern.cpp
@@ -1069,6 +1069,24 @@ unsigned ISel::SelectExpr(SDOperand N) {
     Select(N.getOperand(0));
     ExprMap[N.getValue(Node->getNumValues()-1)] = 1;
 
+    MachineInstr *CallMI;
+    // Emit the correct call instruction based on the type of symbol called.
+    if (GlobalAddressSDNode *GASD = 
+        dyn_cast<GlobalAddressSDNode>(N.getOperand(1))) {
+      CallMI = BuildMI(PPC::CALLpcrel, 1).addGlobalAddress(GASD->getGlobal(), 
+                                                           true);
+    } else if (ExternalSymbolSDNode *ESSDN = 
+               dyn_cast<ExternalSymbolSDNode>(N.getOperand(1))) {
+      CallMI = BuildMI(PPC::CALLpcrel, 1).addExternalSymbol(ESSDN->getSymbol(), 
+                                                            true);
+    } else {
+      Tmp1 = SelectExpr(N.getOperand(1));
+      BuildMI(BB, PPC::OR, 2, PPC::R12).addReg(Tmp1).addReg(Tmp1);
+      BuildMI(BB, PPC::MTCTR, 1).addReg(PPC::R12);
+      CallMI = BuildMI(PPC::CALLindirect, 3).addImm(20).addImm(0)
+        .addReg(PPC::R12);
+    }
+       
     // Load the register args to virtual regs
     std::vector<unsigned> ArgVR;
     for(int i = 2, e = Node->getNumOperands(); i < e; ++i)
@@ -1083,32 +1101,24 @@ unsigned ISel::SelectExpr(SDOperand N) {
       case MVT::i16:
       case MVT::i32:
         assert(GPR_idx < 8 && "Too many int args");
-        if (N.getOperand(i+2).getOpcode() != ISD::UNDEF)
+        if (N.getOperand(i+2).getOpcode() != ISD::UNDEF) {
           BuildMI(BB, PPC::OR,2,GPR[GPR_idx]).addReg(ArgVR[i]).addReg(ArgVR[i]);
+          CallMI->addRegOperand(GPR[GPR_idx], MachineOperand::Use);
+        }
         ++GPR_idx;
         break;
       case MVT::f64:
       case MVT::f32:
         assert(FPR_idx < 13 && "Too many fp args");
         BuildMI(BB, PPC::FMR, 1, FPR[FPR_idx]).addReg(ArgVR[i]);
+        CallMI->addRegOperand(FPR[FPR_idx], MachineOperand::Use);
         ++FPR_idx;
         break;
       }
     }
-
-    // Emit the correct call instruction based on the type of symbol called.
-    if (GlobalAddressSDNode *GASD = 
-        dyn_cast<GlobalAddressSDNode>(N.getOperand(1))) {
-      BuildMI(BB, PPC::CALLpcrel, 1).addGlobalAddress(GASD->getGlobal(), true);
-    } else if (ExternalSymbolSDNode *ESSDN = 
-               dyn_cast<ExternalSymbolSDNode>(N.getOperand(1))) {
-      BuildMI(BB, PPC::CALLpcrel, 1).addExternalSymbol(ESSDN->getSymbol(), true);
-    } else {
-      Tmp1 = SelectExpr(N.getOperand(1));
-      BuildMI(BB, PPC::OR, 2, PPC::R12).addReg(Tmp1).addReg(Tmp1);
-      BuildMI(BB, PPC::MTCTR, 1).addReg(PPC::R12);
-      BuildMI(BB, PPC::CALLindirect, 3).addImm(20).addImm(0).addReg(PPC::R12);
-    }
+    
+    // Put the call instruction in the correct place in the MachineBasicBlock
+    BB->push_back(CallMI);
 
     switch (Node->getValueType(0)) {
     default: assert(0 && "Unknown value type for call result!");