From: David Majnemer <david.majnemer@gmail.com>
Date: Wed, 10 Dec 2014 21:58:17 +0000 (+0000)
Subject: ConstantFold: Clean up X * undef code
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3e04c3e2537911b35d978d584212e1efd6881e82;p=oota-llvm.git

ConstantFold: Clean up X * undef code

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@223970 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/IR/ConstantFold.cpp b/lib/IR/ConstantFold.cpp
index a05c594ac8e..31e962af0b7 100644
--- a/lib/IR/ConstantFold.cpp
+++ b/lib/IR/ConstantFold.cpp
@@ -915,12 +915,14 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
         return C1;
       return Constant::getNullValue(C1->getType());   // undef & X -> 0
     case Instruction::Mul: {
-      ConstantInt *CI;
-      // X * undef -> undef   if X is odd or undef
-      if (((CI = dyn_cast<ConstantInt>(C1)) && CI->getValue()[0]) ||
-          ((CI = dyn_cast<ConstantInt>(C2)) && CI->getValue()[0]) ||
-          (isa<UndefValue>(C1) && isa<UndefValue>(C2)))
-        return UndefValue::get(C1->getType());
+      // undef * undef -> undef
+      if (isa<UndefValue>(C1) && isa<UndefValue>(C2))
+        return C1;
+      const APInt *CV;
+      // X * undef -> undef   if X is odd
+      if (match(C1, m_APInt(CV)) || match(C2, m_APInt(CV)))
+        if ((*CV)[0])
+          return UndefValue::get(C1->getType());
 
       // X * undef -> 0       otherwise
       return Constant::getNullValue(C1->getType());