[analyzer] Unroll the loop when it has a unsigned counter.

Summary:
The original implementation in the `LoopUnrolling.cpp` didn't consider the case where the counter is unsigned. This case is only handled in `simpleCondition()`, but this is not enough, we also need to deal with the unsinged counter with the counter initialization.

Since `IntegerLiteral` is `signed`, there is a `ImplicitCastExpr<IntegralCast>` in `unsigned counter = IntergerLiteral`. This patch add the `ignoringParenImpCasts()` in the `IntegerLiteral` matcher.

Reviewers: szepet, a.sidorin, NoQ, george.karpenkov

Reviewed By: szepet, george.karpenkov

Subscribers: xazax.hun, rnkovacs, cfe-commits, MTC

Differential Revision: https://reviews.llvm.org/D45086

llvm-svn: 328919

1 files changed, 23 insertions, 0 deletions

diff --git a/clang/test/Analysis/loop-unrolling.cpp b/clang/test/Analysis/loop-unrolling.cpp
index aa145ac0af1..ce7ada8bd72 100644
--- a/clang/test/Analysis/loop-unrolling.cpp
+++ b/clang/test/Analysis/loop-unrolling.cpp
@@ -36,6 +36,29 @@ int simple_unroll2() {
   return 0;
 }
 
+int simple_unroll3_unsigned() {
+  int a[9];
+  int k = 42;
+  for (unsigned i = 0; i < 9; i++) {
+    clang_analyzer_numTimesReached(); // expected-warning {{9}}
+    a[i] = 42;
+  }
+  int b = 22 / (k - 42); // expected-warning {{Division by zero}}
+  return 0;
+}
+
+int simple_unroll4_unsigned() {
+  int a[9];
+  int k = 42;
+  unsigned i;
+  for (i = (0); i < 9; i++) {
+    clang_analyzer_numTimesReached(); // expected-warning {{9}}
+    a[i] = 42;
+  }
+  int b = 22 / (k - 42); // expected-warning {{Division by zero}}
+  return 0;
+}
+
 int simple_no_unroll1() {
   int a[9];
   int k = 42;