diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp b/clang/lib/Analysis/UnsafeBufferUsage.cpp
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -163,24 +163,40 @@
 isInUnspecifiedPointerContext(internal::Matcher<Stmt> InnerMatcher) {
   // A UPC can be
   // 1. an argument of a function call (except the callee has [[unsafe_...]]
-  // attribute), or
-  // 2. the operand of a cast operation; or
+  //    attribute), or
+  // 2. the operand of a pointer-to-(integer or bool) cast operation; or
   // 3. the operand of a comparator operation; or
+  // 4. the operand of a pointer subtraction operation
+  //    (i.e., computing the distance between two pointers); or ...
+
   auto CallArgMatcher =
       callExpr(forEachArgumentWithParam(InnerMatcher,
                   hasPointerType() /* array also decays to pointer type*/),
           unless(callee(functionDecl(hasAttr(attr::UnsafeBufferUsage)))));
 
   auto CastOperandMatcher =
-      explicitCastExpr(hasCastKind(CastKind::CK_PointerToIntegral),
-                       castSubExpr(allOf(hasPointerType(), InnerMatcher)));
+      castExpr(anyOf(hasCastKind(CastKind::CK_PointerToIntegral),
+		     hasCastKind(CastKind::CK_PointerToBoolean)),
+	       castSubExpr(allOf(hasPointerType(), InnerMatcher)));
 
   auto CompOperandMatcher =
       binaryOperator(hasAnyOperatorName("!=", "==", "<", "<=", ">", ">="),
                      eachOf(hasLHS(allOf(hasPointerType(), InnerMatcher)),
                             hasRHS(allOf(hasPointerType(), InnerMatcher))));
 
-  return stmt(anyOf(CallArgMatcher, CastOperandMatcher, CompOperandMatcher));
+  // A matcher that matches pointer subtractions:
+  auto PtrSubtractionMatcher =
+      binaryOperator(hasOperatorName("-"),
+		     // Note that here we need both LHS and RHS to be
+		     // pointer. Then the inner matcher can match any of
+		     // them:
+		     allOf(hasLHS(hasPointerType()),
+			   hasRHS(hasPointerType())),
+		     eachOf(hasLHS(InnerMatcher),
+			    hasRHS(InnerMatcher)));
+
+  return stmt(anyOf(CallArgMatcher, CastOperandMatcher, CompOperandMatcher,
+		    PtrSubtractionMatcher));
   // FIXME: any more cases? (UPC excludes the RHS of an assignment.  For now we
   // don't have to check that.)
 }
diff --git a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-addressof-arraysubscript.cpp b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-addressof-arraysubscript.cpp
--- a/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-addressof-arraysubscript.cpp
+++ b/clang/test/SemaCXX/warn-unsafe-buffer-usage-fixits-addressof-arraysubscript.cpp
@@ -13,12 +13,30 @@
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:37-[[@LINE-1]]:42}:"&p.data()[x]"
 }
 
+void address_to_bool(int x) {
+  int * p = new int[10];
+  bool a = (bool) &p[5];
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:19-[[@LINE-1]]:24}:"&p.data()[5]"
+  bool b = (bool) &p[x];
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:19-[[@LINE-1]]:24}:"&p.data()[x]"
+
+  bool a1 = &p[5];
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:13-[[@LINE-1]]:18}:"&p.data()[5]"
+  bool b1 = &p[x];
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:13-[[@LINE-1]]:18}:"&p.data()[x]"
+
+  if (&p[5]) {
+    // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:12}:"&p.data()[5]"
+    return;
+  }
+}
+
 void call_argument(int x) {
   int * p = new int[10];
 
   f((unsigned long) &p[5], &p[x]);
-  // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-1]]:21-[[@LINE-1]]:26}:"&p.data()[5]"
-  // CHECK-DAG: fix-it:"{{.*}}":{[[@LINE-2]]:28-[[@LINE-2]]:33}:"&p.data()[x]"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:21-[[@LINE-1]]:26}:"&p.data()[5]"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:28-[[@LINE-2]]:33}:"&p.data()[x]"
 }
 
 void ignore_unsafe_calls(int x) {
@@ -55,9 +73,26 @@
   // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:5-[[@LINE-1]]:10}:"p.data()"
 }
 
-// CHECK-NOT: fix-it
+void pointer_subtraction(int x) {
+  int * p = new int[10];
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:3-[[@LINE-1]]:12}:"std::span<int> p"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:13-[[@LINE-2]]:13}:"{"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:24-[[@LINE-3]]:24}:", 10}"
+
+  int n = &p[9] - &p[4];
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:11-[[@LINE-1]]:16}:"&p.data()[9]"
+  // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:19-[[@LINE-2]]:24}:"&p.data()[4]"
+  if (&p[9] - &p[x]) {
+    // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:7-[[@LINE-1]]:12}:"&p.data()[9]"
+    // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:15-[[@LINE-2]]:20}:"&p.data()[x]"
+    return;
+  }
+}
+
 // To test multiple function declarations, each of which carries
-// different incomplete informations:
+// different incomplete informations.
+// no fix-it in the rest of this test:
+
 [[clang::unsafe_buffer_usage]]
 void unsafe_g(void*);
 
@@ -65,8 +100,9 @@
 
 void multiple_unsafe_fundecls() {
   int * p = new int[10];
-
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]
   unsafe_g(&p[5]);
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]
 }
 
 void unsafe_h(void*);
@@ -78,6 +114,7 @@
 
 void multiple_unsafe_fundecls2() {
   int * p = new int[10];
-
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]
   unsafe_h(&p[5]);
+  // CHECK-NOT: fix-it:"{{.*}}":{[[@LINE-1]]
 }