From 28145edd30ae5fe5bd82b126cfa739b6146628a5 Mon Sep 17 00:00:00 2001
From: Nate Begeman <natebegeman@mac.com>
Date: Tue, 29 Mar 2005 22:24:51 +0000
Subject: [PATCH] Implement integer select and i1 sign extend

llvm-svn: 20934
---
 llvm/lib/Target/PowerPC/PPC32ISelPattern.cpp | 51 +++++++++++++++++++-
 1 file changed, 49 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/PowerPC/PPC32ISelPattern.cpp b/llvm/lib/Target/PowerPC/PPC32ISelPattern.cpp
index f1b6020670d2..c778021749b0 100644
--- a/llvm/lib/Target/PowerPC/PPC32ISelPattern.cpp
+++ b/llvm/lib/Target/PowerPC/PPC32ISelPattern.cpp
@@ -853,6 +853,9 @@ unsigned ISel::SelectExpr(SDOperand N) {
     case MVT::i8:   
       BuildMI(BB, PPC::EXTSB, 1, Result).addReg(Tmp1); 
       break;
+    case MVT::i1:
+      BuildMI(BB, PPC::SUBFIC, 2, Result).addReg(Tmp1).addSImm(0);
+      break;
     }
     return Result;
     
@@ -1097,8 +1100,52 @@ unsigned ISel::SelectExpr(SDOperand N) {
     assert(0 && "Is this legal?");
     return 0;
     
-  case ISD::SELECT:
-    abort();
+  case ISD::SELECT: {
+    Tmp1 = SelectExpr(N.getOperand(0)); //Cond
+
+    // Create an iterator with which to insert the MBB for copying the false 
+    // value and the MBB to hold the PHI instruction for this SetCC.
+    MachineBasicBlock *thisMBB = BB;
+    const BasicBlock *LLVM_BB = BB->getBasicBlock();
+    ilist<MachineBasicBlock>::iterator It = BB;
+    ++It;
+
+    //  thisMBB:
+    //  ...
+    //   TrueVal = ...
+    //   cmpTY cr0, r1, r2
+    //   bCC copy1MBB
+    //   fallthrough --> copy0MBB
+    BuildMI(BB, PPC::CMPLWI, 2, PPC::CR0).addReg(Tmp1).addImm(0);
+    MachineBasicBlock *copy0MBB = new MachineBasicBlock(LLVM_BB);
+    MachineBasicBlock *sinkMBB = new MachineBasicBlock(LLVM_BB);
+    unsigned TrueValue = SelectExpr(N.getOperand(1)); //Use if TRUE
+    BuildMI(BB, PPC::BNE, 2).addReg(PPC::CR0).addMBB(sinkMBB);
+    MachineFunction *F = BB->getParent();
+    F->getBasicBlockList().insert(It, copy0MBB);
+    F->getBasicBlockList().insert(It, sinkMBB);
+    // Update machine-CFG edges
+    BB->addSuccessor(copy0MBB);
+    BB->addSuccessor(sinkMBB);
+
+    //  copy0MBB:
+    //   %FalseValue = ...
+    //   # fallthrough to sinkMBB
+    BB = copy0MBB;
+    unsigned FalseValue = SelectExpr(N.getOperand(2)); //Use if FALSE
+    // Update machine-CFG edges
+    BB->addSuccessor(sinkMBB);
+
+    //  sinkMBB:
+    //   %Result = phi [ %FalseValue, copy0MBB ], [ %TrueValue, thisMBB ]
+    //  ...
+    BB = sinkMBB;
+    BuildMI(BB, PPC::PHI, 4, Result).addReg(FalseValue)
+      .addMBB(copy0MBB).addReg(TrueValue).addMBB(thisMBB);
+
+    // FIXME: Select i64?
+    return Result;
+  }
 
   case ISD::Constant:
     switch (N.getValueType()) {