From a75d2d04162eb6ea56345c7a02f76eb4b32eb296 Mon Sep 17 00:00:00 2001
From: Bill Wendling <isanbard@gmail.com>
Date: Mon, 15 Aug 2011 21:14:31 +0000
Subject: [PATCH] Duncan pointed out that the LandingPadInst might read memory.
 (It might also write to memory.) Marking it as such makes some checks for
 immobility go away.

llvm-svn: 137655
---
 lib/Analysis/LoopInfo.cpp                           | 3 ---
 lib/Transforms/InstCombine/InstructionCombining.cpp | 5 ++---
 lib/VMCore/Instruction.cpp                          | 2 ++
 3 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/lib/Analysis/LoopInfo.cpp b/lib/Analysis/LoopInfo.cpp
index 36fd598d13c..9a7c50d7fa4 100644
--- a/lib/Analysis/LoopInfo.cpp
+++ b/lib/Analysis/LoopInfo.cpp
@@ -99,9 +99,6 @@ bool Loop::makeLoopInvariant(Instruction *I, bool &Changed,
     return false;
   if (I->mayReadFromMemory())
     return false;
-  // The landingpad instruction is immobile.
-  if (isa<LandingPadInst>(I))
-    return false;
   // Determine the insertion point, unless one was given.
   if (!InsertPt) {
     BasicBlock *Preheader = getLoopPreheader();
diff --git a/lib/Transforms/InstCombine/InstructionCombining.cpp b/lib/Transforms/InstCombine/InstructionCombining.cpp
index 32c55a3408d..41d542af685 100644
--- a/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -1417,9 +1417,8 @@ Instruction *InstCombiner::visitExtractValueInst(ExtractValueInst &EV) {
 static bool TryToSinkInstruction(Instruction *I, BasicBlock *DestBlock) {
   assert(I->hasOneUse() && "Invariants didn't hold!");
 
-  // Cannot move control-flow-involving, volatile loads, vaarg, landingpad, etc.
-  if (isa<PHINode>(I) || isa<LandingPadInst>(I) || I->mayHaveSideEffects() ||
-      isa<TerminatorInst>(I))
+  // Cannot move control-flow-involving, volatile loads, vaarg, etc.
+  if (isa<PHINode>(I) || I->mayHaveSideEffects() || isa<TerminatorInst>(I))
     return false;
 
   // Do not sink alloca instructions out of the entry block.
diff --git a/lib/VMCore/Instruction.cpp b/lib/VMCore/Instruction.cpp
index 22656f3353d..9e55a083db0 100644
--- a/lib/VMCore/Instruction.cpp
+++ b/lib/VMCore/Instruction.cpp
@@ -320,6 +320,7 @@ bool Instruction::mayReadFromMemory() const {
   case Instruction::Fence: // FIXME: refine definition of mayReadFromMemory
   case Instruction::AtomicCmpXchg:
   case Instruction::AtomicRMW:
+  case Instruction::LandingPad:
     return true;
   case Instruction::Call:
     return !cast<CallInst>(this)->doesNotAccessMemory();
@@ -340,6 +341,7 @@ bool Instruction::mayWriteToMemory() const {
   case Instruction::VAArg:
   case Instruction::AtomicCmpXchg:
   case Instruction::AtomicRMW:
+  case Instruction::LandingPad:
     return true;
   case Instruction::Call:
     return !cast<CallInst>(this)->onlyReadsMemory();