From: Chris Lattner <sabre@nondot.org>
Date: Thu, 17 Jun 2004 22:15:25 +0000 (+0000)
Subject: Do not fold loads into instructions if it is used more than once.  In particular
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ccd9796a46883adcc2b29003413a527f078692f7;p=oota-llvm.git

Do not fold loads into instructions if it is used more than once.  In particular
we do not want to fold the load in cases like this:

  X = load
    = add A, X
    = add B, X


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14204 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/InstSelectSimple.cpp b/lib/Target/X86/InstSelectSimple.cpp
index 0c8b0a45667..598a979471a 100644
--- a/lib/Target/X86/InstSelectSimple.cpp
+++ b/lib/Target/X86/InstSelectSimple.cpp
@@ -1964,11 +1964,12 @@ void ISel::visitSimpleBinary(BinaryOperator &B, unsigned OperatorClass) {
 
   // Special case: op Reg, load [mem]
   if (isa<LoadInst>(Op0) && !isa<LoadInst>(Op1) && Class != cLong &&
+      Op0->hasOneUse() && 
       isSafeToFoldLoadIntoInstruction(*cast<LoadInst>(Op0), B))
     if (!B.swapOperands())
       std::swap(Op0, Op1);  // Make sure any loads are in the RHS.
 
-  if (isa<LoadInst>(Op1) && Class != cLong &&
+  if (isa<LoadInst>(Op1) && Class != cLong && Op1->hasOneUse() &&
       isSafeToFoldLoadIntoInstruction(*cast<LoadInst>(Op1), B)) {
 
     unsigned Opcode;
diff --git a/lib/Target/X86/X86ISelSimple.cpp b/lib/Target/X86/X86ISelSimple.cpp
index 0c8b0a45667..598a979471a 100644
--- a/lib/Target/X86/X86ISelSimple.cpp
+++ b/lib/Target/X86/X86ISelSimple.cpp
@@ -1964,11 +1964,12 @@ void ISel::visitSimpleBinary(BinaryOperator &B, unsigned OperatorClass) {
 
   // Special case: op Reg, load [mem]
   if (isa<LoadInst>(Op0) && !isa<LoadInst>(Op1) && Class != cLong &&
+      Op0->hasOneUse() && 
       isSafeToFoldLoadIntoInstruction(*cast<LoadInst>(Op0), B))
     if (!B.swapOperands())
       std::swap(Op0, Op1);  // Make sure any loads are in the RHS.
 
-  if (isa<LoadInst>(Op1) && Class != cLong &&
+  if (isa<LoadInst>(Op1) && Class != cLong && Op1->hasOneUse() &&
       isSafeToFoldLoadIntoInstruction(*cast<LoadInst>(Op1), B)) {
 
     unsigned Opcode;