Delete two if-statements in InstCombineCalls.cpp

[frokaikan]

Summary

These two if-statements check if the 3rd argument of memcpy intrinsic is 1, and then do nothing.
It aims to replace the intrinsic with load/store instruction, but it will be done in the later code.
Consequently, the two if-statements are redundant, and should be removed.

[nikic]

LGTM

[nikic]

Could you please provide Your Name <your@email> to use for the commit?

llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp

Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
   // instead of in visitCallBase.
   if (auto *MI = dyn_cast<AnyMemIntrinsic>(II)) {
     bool Changed = false;
 
     // memmove/cpy/set of zero bytes is a noop.
     if (Constant *NumBytes = dyn_cast<Constant>(MI->getLength())) {
       if (NumBytes->isNullValue())
         return eraseInstFromFunction(CI);
-
-      if (ConstantInt *CI = dyn_cast<ConstantInt>(NumBytes))
-        if (CI->getZExtValue() == 1) {
-          // Replace the instruction with just byte operations.  We would
-          // transform other cases to loads/stores, but we don't know if
-          // alignment is sufficient.
-        }
     }
 
     // No other transformations apply to volatile transfers.
     if (auto *M = dyn_cast<MemIntrinsic>(MI))
       if (M->isVolatile())
         return nullptr;
 
     // If we have a memmove and the source operation is a constant global,