ValueTracking: use getAlignment in isAligned

[apilipenko]

Summary

Separated from D13470.

[reames]

LGTM. Thanks for separating; this is obvious standalone, but I was getting it confused in the last patch.

lib/Analysis/ValueTracking.cpp

3002

Could this check be moved inside getAlignment? If so, that might be a good follow on change?

lib/Analysis/ValueTracking.cpp

if (!Ty->isSized())
     return false;
   
   APInt Offset(DL.getTypeStoreSizeInBits(VTy), 0);
   return isDereferenceableFromAttribute(V, Offset, Ty, DL, CtxI, DT, TLI);
 }
 
 static bool isAligned(const Value *Base, APInt Offset, unsigned Align,
                       const DataLayout &DL) {
-  APInt BaseAlign(Offset.getBitWidth(), 0);
-  if (const AllocaInst *AI = dyn_cast<AllocaInst>(Base))
-    BaseAlign = AI->getAlignment();
-  else if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(Base))
-    BaseAlign = GV->getAlignment();
-  else if (const Argument *A = dyn_cast<Argument>(Base))
-    BaseAlign = A->getParamAlignment();
-  else if (auto CS = ImmutableCallSite(Base))
-    BaseAlign = CS.getAttributes().getParamAlignment(AttributeSet::ReturnIndex);
-  else if (const LoadInst *LI = dyn_cast<LoadInst>(Base))
-    if (MDNode *MD = LI->getMetadata(LLVMContext::MD_align)) {
-      ConstantInt *CI = mdconst::extract<ConstantInt>(MD->getOperand(0));
-      BaseAlign = CI->getLimitedValue();
-    }
+  APInt BaseAlign(Offset.getBitWidth(), getAlignment(Base, DL));
 
   if (!BaseAlign) {
     Type *Ty = Base->getType()->getPointerElementType();
     BaseAlign = DL.getABITypeAlignment(Ty);
   }
 
   APInt Alignment(Offset.getBitWidth(), Align);
 
   assert(Alignment.isPowerOf2() && "must be a power of 2!");
   return BaseAlign.uge(Alignment) && !(Offset & (Alignment-1));