From 4dc8a1eda314b03118daf8dbd1e2c237c8082eea Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Thu, 8 Jul 2010 16:40:22 +0000
Subject: Convert EXTRACT_SUBREG to COPY when emitting machine instrs.

EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.

Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107879 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/MachineCSE.cpp | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'lib/CodeGen/MachineCSE.cpp')

diff --git a/lib/CodeGen/MachineCSE.cpp b/lib/CodeGen/MachineCSE.cpp
index f399c1eba5..833cc00027 100644
--- a/lib/CodeGen/MachineCSE.cpp
+++ b/lib/CodeGen/MachineCSE.cpp
@@ -126,6 +126,28 @@ bool MachineCSE::PerformTrivialCoalescing(MachineInstr *MI,
       ++NumCoalesces;
       Changed = true;
     }
+
+    if (!DefMI->isCopy())
+      continue;
+    SrcReg = DefMI->getOperand(1).getReg();
+    if (!TargetRegisterInfo::isVirtualRegister(SrcReg))
+      continue;
+    if (DefMI->getOperand(0).getSubReg() || DefMI->getOperand(1).getSubReg())
+      continue;
+    const TargetRegisterClass *SRC   = MRI->getRegClass(SrcReg);
+    const TargetRegisterClass *RC    = MRI->getRegClass(Reg);
+    const TargetRegisterClass *NewRC = getCommonSubClass(RC, SRC);
+    if (!NewRC)
+      continue;
+    DEBUG(dbgs() << "Coalescing: " << *DefMI);
+    DEBUG(dbgs() << "*** to: " << *MI);
+    MO.setReg(SrcReg);
+    MRI->clearKillFlags(SrcReg);
+    if (NewRC != SRC)
+      MRI->setRegClass(SrcReg, NewRC);
+    DefMI->eraseFromParent();
+    ++NumCoalesces;
+    Changed = true;
   }
 
   return Changed;
-- 
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