From 7a74bd470368a58e84726b6b25dbd164fab97ae1 Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Sun, 19 Jan 2014 16:48:41 +0000
Subject: InstCombine: Replace a hand-rolled version of isKnownToBeAPowerOfTwo
 with the real thing.

llvm-svn: 199604
---
 .../Transforms/InstCombine/InstCombineAndOrXor.cpp | 25 ++++------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

(limited to 'llvm/lib/Transforms/InstCombine')

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index 88bb69beef0..c520db597c3 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -1543,23 +1543,6 @@ static Instruction *MatchSelectFromAndOr(Value *A, Value *B,
   return 0;
 }
 
-/// IsOneHotValue - Returns true for "one-hot" values (values where at most
-/// one bit can be set).
-static bool IsOneHotValue(Value *V) {
-  // Match 1<<K.
-  if (BinaryOperator *BO = dyn_cast<BinaryOperator>(V))
-    if (BO->getOpcode() == Instruction::Shl) {
-      ConstantInt *One = dyn_cast<ConstantInt>(BO->getOperand(0));
-      return One && One->isOne();
-    }
-
-  // Check for power of two integer constants.
-  if (ConstantInt *K = dyn_cast<ConstantInt>(V))
-    return K->getValue().isPowerOf2();
-
-  return false;
-}
-
 /// FoldOrOfICmps - Fold (icmp)|(icmp) if possible.
 Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
   ICmpInst::Predicate LHSCC = LHS->getPredicate(), RHSCC = RHS->getPredicate();
@@ -1581,13 +1564,13 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
       Value *Mask = 0;
       Value *Masked = 0;
       if (LAnd->getOperand(0) == RAnd->getOperand(0) &&
-          IsOneHotValue(LAnd->getOperand(1)) &&
-          IsOneHotValue(RAnd->getOperand(1))) {
+          isKnownToBeAPowerOfTwo(LAnd->getOperand(1)) &&
+          isKnownToBeAPowerOfTwo(RAnd->getOperand(1))) {
         Mask = Builder->CreateOr(LAnd->getOperand(1), RAnd->getOperand(1));
         Masked = Builder->CreateAnd(LAnd->getOperand(0), Mask);
       } else if (LAnd->getOperand(1) == RAnd->getOperand(1) &&
-                 IsOneHotValue(LAnd->getOperand(0)) &&
-                 IsOneHotValue(RAnd->getOperand(0))) {
+                 isKnownToBeAPowerOfTwo(LAnd->getOperand(0)) &&
+                 isKnownToBeAPowerOfTwo(RAnd->getOperand(0))) {
         Mask = Builder->CreateOr(LAnd->getOperand(0), RAnd->getOperand(0));
         Masked = Builder->CreateAnd(LAnd->getOperand(1), Mask);
       }
-- 
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