PR35131 Fix a misprint in CTLZ recognition

[evstupac]

Summary

Before the patch LLVM include shifts on a register when recognize CTLZ loops.
The patch makes it only shift on a constant 1.

Since this is clear misprint I don't add any new lit test.

[craig.topper]

LGTM

llvm/trunk/lib/Transforms/Scalar/LoopIdiomRecognize.cpp

if (Value *T = matchCondition(
           dyn_cast<BranchInst>(LoopEntry->getTerminator()), LoopEntry))
     DefX = dyn_cast<Instruction>(T);
   else
     return false;
 
   // step 2: detect instructions corresponding to "x.next = x >> 1"
   if (!DefX || DefX->getOpcode() != Instruction::AShr)
     return false;
-  if (ConstantInt *Shft = dyn_cast<ConstantInt>(DefX->getOperand(1)))
-    if (!Shft || !Shft->isOne())
-      return false;
+  ConstantInt *Shft = dyn_cast<ConstantInt>(DefX->getOperand(1));
   VarX = DefX->getOperand(0);
 
   // step 3: Check the recurrence of variable X
   PhiX = getRecurrenceVar(VarX, DefX, LoopEntry);
   if (!PhiX)
     return false;
 
   // step 4: Find the instruction which count the CTLZ: cnt.next = cnt + 1