From: Craig Topper <craig.topper@gmail.com>
Date: Thu, 6 Apr 2017 16:42:46 +0000 (+0000)
Subject: [InstCombine] Fix a case where we weren't checking that an instruction had a single... 
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ba2269c0f0633dfbb85b26d3a217e5f4ae47744a;p=llvm

[InstCombine] Fix a case where we weren't checking that an instruction had a single use resulting in extra instructions being created.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@299658 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index e764033dd2e..1761fcf455b 100644
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1332,18 +1332,21 @@ Instruction *InstCombiner::visitAnd(BinaryOperator &I) {
         // ((A & N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == AndRHS.
         // ((A | N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
         // ((A ^ N) + B) & AndRHS -> (A + B) & AndRHS iff N&AndRHS == 0
-        if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
-          return BinaryOperator::CreateAnd(V, AndRHS);
-        if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
-          return BinaryOperator::CreateAnd(V, AndRHS);  // Add commutes
+        if (Op0I->hasOneUse()) {
+          if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, false, I))
+            return BinaryOperator::CreateAnd(V, AndRHS);
+          if (Value *V = FoldLogicalPlusAnd(Op0RHS, Op0LHS, AndRHS, false, I))
+            return BinaryOperator::CreateAnd(V, AndRHS);  // Add commutes
+        }
         break;
 
       case Instruction::Sub:
         // ((A & N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == AndRHS.
         // ((A | N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
         // ((A ^ N) - B) & AndRHS -> (A - B) & AndRHS iff N&AndRHS == 0
-        if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
-          return BinaryOperator::CreateAnd(V, AndRHS);
+        if (Op0I->hasOneUse())
+          if (Value *V = FoldLogicalPlusAnd(Op0LHS, Op0RHS, AndRHS, true, I))
+            return BinaryOperator::CreateAnd(V, AndRHS);
 
         // -x & 1 -> x & 1
         if (AndRHSMask == 1 && match(Op0LHS, m_Zero()))