Fixing the formatting issue and added tests.

Author: MalavikaSamak

clang/lib/Analysis/UnsafeBufferUsage.cpp

@@ -606,13 +606,13 @@ static bool isSafeArraySubscript(const ArraySubscriptExpr &Node,
     const Expr *LHS = BE->getLHS();
     const Expr *RHS = BE->getRHS();
 
-    if(BE->getOpcode() == BO_Rem) {
+    if (BE->getOpcode() == BO_Rem) {
       // If n is a negative number, then n % const can be greater than const
-      if(!LHS->getType()->isUnsignedIntegerType()) {
+      if (!LHS->getType()->isUnsignedIntegerType()) {
         return false;
       }
 
-      if(!RHS->isValueDependent() && RHS->EvaluateAsInt(EVResult, Ctx)) {
+      if (!RHS->isValueDependent() && RHS->EvaluateAsInt(EVResult, Ctx)) {
         llvm::APSInt result = EVResult.Val.getInt();
         if (result.isNonNegative() && result.getLimitedValue() <= limit)
           return true;

clang/test/SemaCXX/warn-unsafe-buffer-usage-array.cpp

@@ -35,13 +35,19 @@ void constant_idx_safe0(unsigned idx) {
   buffer[0] = 0;
 }
 
-int array[10]; // expected-warning 2{{'array' is an unsafe buffer that does not perform bounds checks}}
+int array[10]; // expected-warning 3{{'array' is an unsafe buffer that does not perform bounds checks}}
 
-void circular_access_safe(unsigned idx) {
+void circular_access_unsigned(unsigned idx) {
   array[idx % 10];
+  array[idx % 11]; // expected-note {{used in buffer access here}}
+  array[(idx + 3) % 10];
+  array[(--idx) % 8];
+  array[idx & 9 % 10];
+  array[9 & idx % 11];
+  array [12 % 10];
 }
 
-void circular_access_unsafe(int idx) {
+void circular_access_signed(int idx) {
   array[idx % 10]; // expected-note {{used in buffer access here}}
 }