Index: llvm/lib/Analysis/LoopAccessAnalysis.cpp
===================================================================
--- llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -712,11 +712,12 @@
 
   // We assign a consecutive id to access from different alias sets.
   // Accesses between different groups doesn't need to be checked.
-  unsigned ASId = 1;
+  unsigned ASId = 0;
   for (auto &AS : AST) {
     int NumReadPtrChecks = 0;
     int NumWritePtrChecks = 0;
     bool CanDoAliasSetRT = true;
+    ++ASId;
 
     // We assign consecutive id to access from different dependence sets.
     // Accesses within the same set don't need a runtime check.
@@ -752,9 +753,25 @@
     // we have a pointer for which we couldn't find the bounds but we don't
     // actually need to emit any checks so it does not matter.
     bool NeedsAliasSetRTCheck = false;
-    if (!(IsDepCheckNeeded && CanDoAliasSetRT && RunningDepId == 2))
+    if (!(IsDepCheckNeeded && CanDoAliasSetRT && RunningDepId == 2)) {
       NeedsAliasSetRTCheck = (NumWritePtrChecks >= 2 ||
                              (NumReadPtrChecks >= 1 && NumWritePtrChecks >= 1));
+      // For alias sets without at least 2 writes or 1 write and 1 read, there
+      // is no need to generate RT checks and CanDoAliasSetRT for this alias set
+      // does not impact whether runtime checks can be generated.
+      if (!NeedsAliasSetRTCheck) {
+        assert((AS.size() <= 1 ||
+                all_of(AS,
+                       [this](auto AC) {
+                         MemAccessInfo AccessWrite(AC.getValue(), true);
+                         return DepCands.findValue(AccessWrite) ==
+                                DepCands.end();
+                       })) &&
+               "Can only skip updating CanDoRT below, if all entries in AS "
+               "are reads or there is at most 1 entry");
+        continue;
+      }
+    }
 
     // We need to perform run-time alias checks, but some pointers had bounds
     // that couldn't be checked.
Index: llvm/test/Transforms/LoopVectorize/alias-set-with-uncomputable-bounds.ll
===================================================================
--- /dev/null
+++ llvm/test/Transforms/LoopVectorize/alias-set-with-uncomputable-bounds.ll
@@ -0,0 +1,150 @@
+; RUN: opt  -loop-vectorize -force-vector-width=2 -S %s | FileCheck %s
+
+; Tests with alias sets that contain points with uncomputable bounds because
+; they include %offset.1, which is loaded in each loop iteration.
+
+; Alias set with uncomputable bounds contains a single load. We do not need
+; runtime checks for that group and it should not block vectorization.
+define void @test1_uncomputable_bounds_single_load(i32* noalias %ptr.1, i32* noalias %ptr.2, i32* noalias %ptr.3, i64 %N, i64 %X) {
+; CHECK-LABEL: define void @test1_uncomputable_bounds_single_load
+; CHECK:       vector.body
+; CHECK:         ret void
+
+entry:
+  %cond = icmp sgt i64 %N, 0
+  br i1 %cond, label %ph, label %exit
+
+ph:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %ph ], [ %iv.next, %loop ]
+  %gep.1 = getelementptr inbounds i32, i32* %ptr.3, i64 %iv
+  %offset.1 = load i32, i32* %gep.1, align 4
+  %gep.2 = getelementptr inbounds i32, i32* %ptr.2, i32 %offset.1
+  %lv = load i32, i32* %gep.2, align 4
+  %gep.3 = getelementptr inbounds i32, i32* %ptr.1, i64 %iv
+  store i32 %lv , i32* %gep.3, align 4
+  %offset.2 = add nsw i64 %iv, %X
+  %gep.4 = getelementptr inbounds i32, i32* %ptr.1, i64 %offset.2
+  store i32 %lv, i32* %gep.4, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, %N
+  br i1 %exitcond, label %loop.exit, label %loop
+
+loop.exit:
+  br label %exit
+
+exit:
+  ret void
+}
+
+; Alias set with uncomputable bounds contains a single store. We do not need
+; runtime checks for that group and it should not block vectorization.
+define void @test2_uncomputable_bounds_single_store(i32* noalias %ptr.1, i32* noalias %ptr.2, i32* noalias %ptr.3, i64 %N, i64 %X) {
+; CHECK-LABEL: define void @test2_uncomputable_bounds_single_store
+; CHECK:       vector.body
+; CHECK:         ret void
+
+entry:
+  %cond = icmp sgt i64 %N, 0
+  br i1 %cond, label %ph, label %exit
+
+ph:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %ph ], [ %iv.next, %loop ]
+  %gep.1 = getelementptr inbounds i32, i32* %ptr.3, i64 %iv
+  %offset.1 = load i32, i32* %gep.1, align 4
+  %gep.2 = getelementptr inbounds i32, i32* %ptr.2, i32 %offset.1
+  store i32 20, i32* %gep.2, align 4
+  %gep.3 = getelementptr inbounds i32, i32* %ptr.1, i64 %iv
+  store i32 0 , i32* %gep.3, align 4
+  %offset.2 = add nsw i64 %iv, %X
+  %gep.4 = getelementptr inbounds i32, i32* %ptr.1, i64 %offset.2
+  store i32 10, i32* %gep.4, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, %N
+  br i1 %exitcond, label %loop.exit, label %loop
+
+loop.exit:
+  br label %exit
+
+exit:
+  ret void
+}
+
+; Alias set with uncomputable bounds contains a load and a store. This blocks
+; vectorization, as we cannot generate runtime-checks for the set.
+define void @test3_uncomputable_bounds_load_store(i32* noalias %ptr.1, i32* noalias %ptr.2, i32* noalias %ptr.3, i64 %N, i64 %X) {
+; CHECK-LABEL: define void @test3_uncomputable_bounds_load_store
+; CHECK-NOT: vector.body
+
+entry:
+  %cond = icmp sgt i64 %N, 0
+  br i1 %cond, label %ph, label %exit
+
+ph:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %ph ], [ %iv.next, %loop ]
+  %gep.1 = getelementptr inbounds i32, i32* %ptr.3, i64 %iv
+  %offset.1 = load i32, i32* %gep.1, align 4
+  %gep.2 = getelementptr inbounds i32, i32* %ptr.2, i32 %offset.1
+  store i32 20, i32* %gep.2, align 4
+  %gep.22 = getelementptr inbounds i32, i32* %ptr.2, i64 %iv
+  %lv = load i32, i32* %gep.22, align 4
+  %gep.3 = getelementptr inbounds i32, i32* %ptr.1, i64 %iv
+  store i32 %lv , i32* %gep.3, align 4
+  %offset.2 = add nsw i64 %iv, %X
+  %gep.4 = getelementptr inbounds i32, i32* %ptr.1, i64 %offset.2
+  store i32 %lv, i32* %gep.4, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, %N
+  br i1 %exitcond, label %loop.exit, label %loop
+
+loop.exit:
+  br label %exit
+
+exit:
+  ret void
+}
+
+; Alias set with uncomputable bounds contains a load and a store. This blocks
+; vectorization, as we cannot generate runtime-checks for the set.
+define void @test4_uncomputable_bounds_store_store(i32* noalias %ptr.1, i32* noalias %ptr.2, i32* noalias %ptr.3, i64 %N, i64 %X) {
+; CHECK-LABEL: define void @test4_uncomputable_bounds_store_store
+; CHECK-NOT: vector.body
+
+entry:
+  %cond = icmp sgt i64 %N, 0
+  br i1 %cond, label %ph, label %exit
+
+ph:
+  br label %loop
+
+loop:
+  %iv = phi i64 [ 0, %ph ], [ %iv.next, %loop ]
+  %gep.1 = getelementptr inbounds i32, i32* %ptr.3, i64 %iv
+  %offset.1 = load i32, i32* %gep.1, align 4
+  %gep.2 = getelementptr inbounds i32, i32* %ptr.2, i32 %offset.1
+  store i32 20, i32* %gep.2, align 4
+  %gep.22 = getelementptr inbounds i32, i32* %ptr.2, i64 %iv
+  store i32 30, i32* %gep.22, align 4
+  %gep.3 = getelementptr inbounds i32, i32* %ptr.1, i64 %iv
+  store i32 0 , i32* %gep.3, align 4
+  %offset.2 = add nsw i64 %iv, %X
+  %gep.4 = getelementptr inbounds i32, i32* %ptr.1, i64 %offset.2
+  store i32 10, i32* %gep.4, align 4
+  %iv.next = add nuw nsw i64 %iv, 1
+  %exitcond = icmp eq i64 %iv.next, %N
+  br i1 %exitcond, label %loop.exit, label %loop
+
+loop.exit:
+  br label %exit
+
+exit:
+  ret void
+}