PR16074, implement warnings to catch pointer to boolean true and pointer to

null comparison when the pointer is known to be non-null.

This catches the array to pointer decay, function to pointer decay and
address of variables.  This does not catch address of function since this
has been previously used to silence a warning.

Pointer to bool conversion is under -Wbool-conversion.
Pointer to null comparison is under -Wtautological-pointer-compare, a sub-group
of -Wtautological-compare.

void foo() {
  int arr[5];
  int x;
  // warn on these conditionals
  if (foo);
  if (arr);
  if (&x);
  if (foo == null);
  if (arr == null);
  if (&x == null);

  if (&foo);  // no warning
}

llvm-svn: 202216

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/test/CXX/expr/expr.unary/expr.unary.op/p6.cpp b/clang/test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
index 2646264273e..833a4014e86 100644
--- a/clang/test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
+++ b/clang/test/CXX/expr/expr.unary/expr.unary.op/p6.cpp
@@ -15,7 +15,7 @@ bool b4 = !E;
 bool b5 = !F;
 
 // --  pointer, 
-bool b6 = !&b4;
+bool b6 = !&b4; // expected-warning{{address of 'b4' will always evaluate to 'true'}}
 void f();
 bool b61 = !&f;