From 7ec38530a53e801e8f5f824eca2b29ac3f42622f Mon Sep 17 00:00:00 2001
From: Jingyue Wu <jingyue@google.com>
Date: Wed, 29 Jul 2015 15:26:11 +0000
Subject: [PATCH] Temporarily revert r242871

PR24299

llvm-svn: 243522
---
 llvm/lib/CodeGen/BranchFolding.cpp           | 43 ++++++++++------------------
 llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp |  1 +
 llvm/test/CodeGen/NVPTX/branch-fold.ll       | 24 ----------------
 3 files changed, 16 insertions(+), 52 deletions(-)
 delete mode 100644 llvm/test/CodeGen/NVPTX/branch-fold.ll

diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index 608f021..6182667 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -12,8 +12,7 @@
 // it then removes.
 //
 // Note that this pass must be run after register allocation, it cannot handle
-// SSA form. It also must handle virtual registers for targets that emit virtual
-// ISA (e.g. NVPTX).
+// SSA form.
 //
 //===----------------------------------------------------------------------===//
 
@@ -1574,17 +1573,6 @@ static MachineBasicBlock *findFalseBlock(MachineBasicBlock *BB,
   return nullptr;
 }
 
-template <class Container>
-static void addRegAndItsAliases(unsigned Reg, const TargetRegisterInfo *TRI,
-                                Container &Set) {
-  if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
-    for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
-      Set.insert(*AI);
-  } else {
-    Set.insert(Reg);
-  }
-}
-
 /// findHoistingInsertPosAndDeps - Find the location to move common instructions
 /// in successors to. The location is usually just before the terminator,
 /// however if the terminator is a conditional branch and its previous
@@ -1610,7 +1598,8 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB,
     if (!Reg)
       continue;
     if (MO.isUse()) {
-      addRegAndItsAliases(Reg, TRI, Uses);
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        Uses.insert(*AI);
     } else {
       if (!MO.isDead())
         // Don't try to hoist code in the rare case the terminator defines a
@@ -1619,7 +1608,8 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB,
 
       // If the terminator defines a register, make sure we don't hoist
       // the instruction whose def might be clobbered by the terminator.
-      addRegAndItsAliases(Reg, TRI, Defs);
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        Defs.insert(*AI);
     }
   }
 
@@ -1675,15 +1665,15 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB,
     if (!Reg)
       continue;
     if (MO.isUse()) {
-      addRegAndItsAliases(Reg, TRI, Uses);
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        Uses.insert(*AI);
     } else {
       if (Uses.erase(Reg)) {
-        if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
-          for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
-            Uses.erase(*SubRegs); // Use sub-registers to be conservative
-        }
+        for (MCSubRegIterator SubRegs(Reg, TRI); SubRegs.isValid(); ++SubRegs)
+          Uses.erase(*SubRegs); // Use sub-registers to be conservative
       }
-      addRegAndItsAliases(Reg, TRI, Defs);
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        Defs.insert(*AI);
     }
   }
 
@@ -1810,12 +1800,8 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
       unsigned Reg = MO.getReg();
       if (!Reg || !LocalDefsSet.count(Reg))
         continue;
-      if (TargetRegisterInfo::isPhysicalRegister(Reg)) {
-        for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
-          LocalDefsSet.erase(*AI);
-      } else {
-        LocalDefsSet.erase(Reg);
-      }
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        LocalDefsSet.erase(*AI);
     }
 
     // Track local defs so we can update liveins.
@@ -1827,7 +1813,8 @@ bool BranchFolder::HoistCommonCodeInSuccs(MachineBasicBlock *MBB) {
       if (!Reg)
         continue;
       LocalDefs.push_back(Reg);
-      addRegAndItsAliases(Reg, TRI, LocalDefsSet);
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        LocalDefsSet.insert(*AI);
     }
 
     HasDups = true;
diff --git a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
index 706314c..37440d0 100644
--- a/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXTargetMachine.cpp
@@ -174,6 +174,7 @@ void NVPTXPassConfig::addIRPasses() {
   // NVPTXPrologEpilog pass (see NVPTXPrologEpilogPass.cpp).
   disablePass(&PrologEpilogCodeInserterID);
   disablePass(&MachineCopyPropagationID);
+  disablePass(&BranchFolderPassID);
   disablePass(&TailDuplicateID);
 
   addPass(createNVPTXImageOptimizerPass());
diff --git a/llvm/test/CodeGen/NVPTX/branch-fold.ll b/llvm/test/CodeGen/NVPTX/branch-fold.ll
deleted file mode 100644
index 305235b..0000000
--- a/llvm/test/CodeGen/NVPTX/branch-fold.ll
+++ /dev/null
@@ -1,24 +0,0 @@
-; RUN: llc < %s -march=nvptx64 -mcpu=sm_35 -disable-cgp | FileCheck %s
-; Disable CGP which also folds branches, so that only BranchFolding is under
-; the spotlight.
-
-target datalayout = "e-i64:64-v16:16-v32:32-n16:32:64"
-target triple = "nvptx64-nvidia-cuda"
-
-define void @foo(i32 %x, float* %output) {
-; CHECK-LABEL: .visible .func foo(
-; CHECK-NOT: bra.uni
-; CHECK-NOT: LBB0_
-  %1 = icmp eq i32 %x, 1
-  br i1 %1, label %then, label %else
-
-then:
-  br label %merge
-
-else:
-  br label %merge
-
-merge:
-  store float 2.0, float* %output
-  ret void
-}
-- 
2.7.4