Added a path-sensitive idempotent operation checker (-analyzer-idempotent-operation). Finds idempotent and/or tautological operations in a path sensitive context, flagging operations that have no effect or a predictable effect.

Example:
{
int a = 1;
int b = 5;
int c = b / a; // a is 1 on all paths
}

- New IdempotentOperationChecker class
- Moved recursive Stmt functions in r107675 to IdempotentOperationChecker
- Minor refactoring of SVal to allow checking for any integer
- Added command line option for check
- Added basic test cases

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@107706 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 3 deletions

diff --git a/lib/Checker/SVals.cpp b/lib/Checker/SVals.cpp
index d756be70dc..7a99e8681d 100644
--- a/lib/Checker/SVals.cpp
+++ b/lib/Checker/SVals.cpp
@@ -200,15 +200,19 @@ bool SVal::isConstant() const {
   return isa<nonloc::ConcreteInt>(this) || isa<loc::ConcreteInt>(this);
 }
 
-bool SVal::isZeroConstant() const {
+bool SVal::isConstant(int I) const {
   if (isa<loc::ConcreteInt>(*this))
-    return cast<loc::ConcreteInt>(*this).getValue() == 0;
+    return cast<loc::ConcreteInt>(*this).getValue() == I;
   else if (isa<nonloc::ConcreteInt>(*this))
-    return cast<nonloc::ConcreteInt>(*this).getValue() == 0;
+    return cast<nonloc::ConcreteInt>(*this).getValue() == I;
   else
     return false;
 }
 
+bool SVal::isZeroConstant() const {
+  return isConstant(0);
+}
+
 
 //===----------------------------------------------------------------------===//
 // Transfer function dispatch for Non-Locs.