From 0d23e8b50415ea0841a4d0185b51c1bae69d2c49 Mon Sep 17 00:00:00 2001
From: Kai Luo <lkail@cn.ibm.com>
Date: Wed, 26 Jun 2019 01:34:37 +0000
Subject: [PATCH] [PowerPC][NFC] Move peephole optimization of RLDICR into a
 method.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@364372 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/PowerPC/PPCMIPeephole.cpp | 104 +++++++++++++++------------
 1 file changed, 57 insertions(+), 47 deletions(-)

diff --git a/lib/Target/PowerPC/PPCMIPeephole.cpp b/lib/Target/PowerPC/PPCMIPeephole.cpp
index 9a566eddfdd..6e693bd1db2 100644
--- a/lib/Target/PowerPC/PPCMIPeephole.cpp
+++ b/lib/Target/PowerPC/PPCMIPeephole.cpp
@@ -94,6 +94,7 @@ private:
   // Perform peepholes.
   bool eliminateRedundantCompare(void);
   bool eliminateRedundantTOCSaves(std::map<MachineInstr *, bool> &TOCSaves);
+  void emitRLDICWhenLoweringJumpTables(MachineInstr &MI);
   void UpdateTOCSaves(std::map<MachineInstr *, bool> &TOCSaves,
                       MachineInstr *MI);
 
@@ -760,53 +761,7 @@ bool PPCMIPeephole::simplifyCode(void) {
         break;
       }
       case PPC::RLDICR: {
-        // We miss the opportunity to emit an RLDIC when lowering jump tables
-        // since ISEL sees only a single basic block. When selecting, the clear
-        // and shift left will be in different blocks.
-        unsigned SrcReg = MI.getOperand(1).getReg();
-        if (!TargetRegisterInfo::isVirtualRegister(SrcReg))
-          break;
-
-        MachineInstr *SrcMI = MRI->getVRegDef(SrcReg);
-        if (SrcMI->getOpcode() != PPC::RLDICL)
-          break;
-        MachineOperand MOpSHSrc = SrcMI->getOperand(2);
-        MachineOperand MOpMBSrc = SrcMI->getOperand(3);
-        MachineOperand MOpSHMI = MI.getOperand(2);
-        MachineOperand MOpMEMI = MI.getOperand(3);
-        if (!(MOpSHSrc.isImm() && MOpMBSrc.isImm() &&
-              MOpSHMI.isImm() && MOpMEMI.isImm()))
-          break;
-        uint64_t SHSrc = MOpSHSrc.getImm();
-        uint64_t MBSrc = MOpMBSrc.getImm();
-        uint64_t SHMI = MOpSHMI.getImm();
-        uint64_t MEMI = MOpMEMI.getImm();
-        uint64_t NewSH = SHSrc + SHMI;
-        uint64_t NewMB = MBSrc - SHMI;
-        if (NewMB > 63 || NewSH > 63)
-          break;
-
-        // The bits cleared with RLDICL are [0, MBSrc).
-        // The bits cleared with RLDICR are (MEMI, 63].
-        // After the sequence, the bits cleared are:
-        // [0, MBSrc-SHMI) and (MEMI, 63).
-        //
-        // The bits cleared with RLDIC are [0, NewMB) and (63-NewSH, 63].
-        if ((63 - NewSH) != MEMI)
-          break;
-
-        LLVM_DEBUG(dbgs() << "Converting pair: ");
-        LLVM_DEBUG(SrcMI->dump());
-        LLVM_DEBUG(MI.dump());
-
-        MI.setDesc(TII->get(PPC::RLDIC));
-        MI.getOperand(1).setReg(SrcMI->getOperand(1).getReg());
-        MI.getOperand(2).setImm(NewSH);
-        MI.getOperand(3).setImm(NewMB);
-
-        LLVM_DEBUG(dbgs() << "To: ");
-        LLVM_DEBUG(MI.dump());
-        NumRotatesCollapsed++;
+        emitRLDICWhenLoweringJumpTables(MI);
         break;
       }
       }
@@ -1326,6 +1281,61 @@ bool PPCMIPeephole::eliminateRedundantCompare(void) {
   return Simplified;
 }
 
+// We miss the opportunity to emit an RLDIC when lowering jump tables
+// since ISEL sees only a single basic block. When selecting, the clear
+// and shift left will be in different blocks.
+void PPCMIPeephole::emitRLDICWhenLoweringJumpTables(MachineInstr &MI) {
+  if (MI.getOpcode() != PPC::RLDICR)
+    return;
+
+  unsigned SrcReg = MI.getOperand(1).getReg();
+  if (!TargetRegisterInfo::isVirtualRegister(SrcReg))
+    return;
+
+  MachineInstr *SrcMI = MRI->getVRegDef(SrcReg);
+  if (SrcMI->getOpcode() != PPC::RLDICL)
+    return;
+
+  MachineOperand MOpSHSrc = SrcMI->getOperand(2);
+  MachineOperand MOpMBSrc = SrcMI->getOperand(3);
+  MachineOperand MOpSHMI = MI.getOperand(2);
+  MachineOperand MOpMEMI = MI.getOperand(3);
+  if (!(MOpSHSrc.isImm() && MOpMBSrc.isImm() && MOpSHMI.isImm() &&
+        MOpMEMI.isImm()))
+    return;
+
+  uint64_t SHSrc = MOpSHSrc.getImm();
+  uint64_t MBSrc = MOpMBSrc.getImm();
+  uint64_t SHMI = MOpSHMI.getImm();
+  uint64_t MEMI = MOpMEMI.getImm();
+  uint64_t NewSH = SHSrc + SHMI;
+  uint64_t NewMB = MBSrc - SHMI;
+  if (NewMB > 63 || NewSH > 63)
+    return;
+
+  // The bits cleared with RLDICL are [0, MBSrc).
+  // The bits cleared with RLDICR are (MEMI, 63].
+  // After the sequence, the bits cleared are:
+  // [0, MBSrc-SHMI) and (MEMI, 63).
+  //
+  // The bits cleared with RLDIC are [0, NewMB) and (63-NewSH, 63].
+  if ((63 - NewSH) != MEMI)
+    return;
+
+  LLVM_DEBUG(dbgs() << "Converting pair: ");
+  LLVM_DEBUG(SrcMI->dump());
+  LLVM_DEBUG(MI.dump());
+
+  MI.setDesc(TII->get(PPC::RLDIC));
+  MI.getOperand(1).setReg(SrcMI->getOperand(1).getReg());
+  MI.getOperand(2).setImm(NewSH);
+  MI.getOperand(3).setImm(NewMB);
+
+  LLVM_DEBUG(dbgs() << "To: ");
+  LLVM_DEBUG(MI.dump());
+  NumRotatesCollapsed++;
+}
+
 } // end default namespace
 
 INITIALIZE_PASS_BEGIN(PPCMIPeephole, DEBUG_TYPE,
-- 
2.40.0