Index: lib/Analysis/ConstantFolding.cpp
===================================================================
--- lib/Analysis/ConstantFolding.cpp
+++ lib/Analysis/ConstantFolding.cpp
@@ -1170,7 +1170,9 @@
                                                 const DataLayout &DL,
                                                 const TargetLibraryInfo *TLI) {
   // fold: icmp (inttoptr x), null         -> icmp x, 0
+  // fold: icmp null, (inttoptr x)         -> icmp 0, x
   // fold: icmp (ptrtoint x), 0            -> icmp x, null
+  // fold: icmp 0, (ptrtoint x)            -> icmp null, x
   // fold: icmp (inttoptr x), (inttoptr y) -> icmp trunc/zext x, trunc/zext y
   // fold: icmp (ptrtoint x), (ptrtoint y) -> icmp x, y
   //
@@ -1240,6 +1242,29 @@
         Predicate == ICmpInst::ICMP_EQ ? Instruction::And : Instruction::Or;
       return ConstantFoldBinaryOpOperands(OpC, LHS, RHS, DL);
     }
+  } else if (auto *CE1 = dyn_cast<ConstantExpr>(Ops1)) {
+    if (Ops0->isNullValue()) {
+      if (CE1->getOpcode() == Instruction::IntToPtr) {
+        Type *IntPtrTy = DL.getIntPtrType(CE1->getType());
+        // Convert the integer value to the right size to ensure we get the
+        // proper extension or truncation.
+        Constant *C = ConstantExpr::getIntegerCast(CE1->getOperand(0),
+                                                   IntPtrTy, false);
+        Constant *Null = Constant::getNullValue(C->getType());
+        return ConstantFoldCompareInstOperands(Predicate, Null, C, DL, TLI);
+      }
+
+      // Only do this transformation if the int is intptrty in size, otherwise
+      // there is a truncation or extension that we aren't modeling.
+      if (CE1->getOpcode() == Instruction::PtrToInt) {
+        Type *IntPtrTy = DL.getIntPtrType(CE1->getOperand(0)->getType());
+        if (CE1->getType() == IntPtrTy) {
+          Constant *C = CE1->getOperand(0);
+          Constant *Null = Constant::getNullValue(C->getType());
+          return ConstantFoldCompareInstOperands(Predicate, Null, C, DL, TLI);
+        }
+      }
+    }
   }
 
   return ConstantExpr::getCompare(Predicate, Ops0, Ops1);
Index: test/Transforms/InstSimplify/compare.ll
===================================================================
--- test/Transforms/InstSimplify/compare.ll
+++ test/Transforms/InstSimplify/compare.ll
@@ -1289,7 +1289,7 @@
 
 define i1 @constant_fold_null_inttoptr() {
 ; CHECK-LABEL: @constant_fold_null_inttoptr(
-; CHECK-NEXT:    ret i1 icmp eq (i32* inttoptr (i64 32 to i32*), i32* null)
+; CHECK-NEXT:    ret i1 false
 ;
   %x = icmp eq i32* null, inttoptr (i64 32 to i32*)
   ret i1 %x