[ValueTracking] Move MD_range handling to isKnownNonZeroFromOperator()

All the isKnownNonZero() handling for instructions should be inside
this function. This makes the structure more similar to
computeKnownBitsFromOperator() as well.

This may not be entirely NFC due to different depth handling.

Author: nikic

llvm/lib/Analysis/ValueTracking.cpp

@@ -2759,27 +2759,33 @@ static bool isKnownNonZeroFromOperator(const Operator *I,
     auto *LI = cast<LoadInst>(I);
     // A Load tagged with nonnull or dereferenceable with null pointer undefined
     // is never null.
-    if (auto *PtrT = dyn_cast<PointerType>(I->getType()))
+    if (auto *PtrT = dyn_cast<PointerType>(I->getType())) {
       if (Q.IIQ.getMetadata(LI, LLVMContext::MD_nonnull) ||
           (Q.IIQ.getMetadata(LI, LLVMContext::MD_dereferenceable) &&
            !NullPointerIsDefined(LI->getFunction(), PtrT->getAddressSpace())))
         return true;
+    } else if (MDNode *Ranges = Q.IIQ.getMetadata(LI, LLVMContext::MD_range)) {
+      return rangeMetadataExcludesValue(Ranges, APInt::getZero(BitWidth));
+    }
 
     // No need to fall through to computeKnownBits as range metadata is already
     // handled in isKnownNonZero.
     return false;
   }
   case Instruction::Call:
-  case Instruction::Invoke:
+  case Instruction::Invoke: {
+    const auto *Call = cast<CallBase>(I);
     if (I->getType()->isPointerTy()) {
-      const auto *Call = cast<CallBase>(I);
       if (Call->isReturnNonNull())
         return true;
       if (const auto *RP = getArgumentAliasingToReturnedPointer(Call, true))
         return isKnownNonZero(RP, Depth, Q);
-    } else if (const Value *RV = cast<CallBase>(I)->getReturnedArgOperand()) {
-      if (RV->getType() == I->getType() && isKnownNonZero(RV, Depth, Q))
-        return true;
+    } else {
+      if (MDNode *Ranges = Q.IIQ.getMetadata(Call, LLVMContext::MD_range))
+        return rangeMetadataExcludesValue(Ranges, APInt::getZero(BitWidth));
+      if (const Value *RV = Call->getReturnedArgOperand())
+        if (RV->getType() == I->getType() && isKnownNonZero(RV, Depth, Q))
+          return true;
     }
 
     if (auto *II = dyn_cast<IntrinsicInst>(I)) {
@@ -2849,6 +2855,7 @@ static bool isKnownNonZeroFromOperator(const Operator *I,
 
     return false;
   }
+  }
 
   KnownBits Known(BitWidth);
   computeKnownBits(I, DemandedElts, Known, Depth, Q);
@@ -2914,17 +2921,6 @@ bool isKnownNonZero(const Value *V, const APInt &DemandedElts, unsigned Depth,
       return false;
   }
 
-  if (auto *I = dyn_cast<Instruction>(V)) {
-    if (MDNode *Ranges = Q.IIQ.getMetadata(I, LLVMContext::MD_range)) {
-      // If the possible ranges don't contain zero, then the value is
-      // definitely non-zero.
-      assert(Ty->isIntOrIntVectorTy() && "Range on non-integer?");
-      const APInt ZeroValue(Ty->getScalarSizeInBits(), 0);
-      if (rangeMetadataExcludesValue(Ranges, ZeroValue))
-        return true;
-    }
-  }
-
   if (!isa<Constant>(V) && isKnownNonZeroFromAssume(V, Q))
     return true;