3 files changed, 34 insertions, 2 deletions
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index bf1101f0f4c..d0518b98570 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -67,6 +67,9 @@ def warn_wrong_absolute_value_type : Warning<
   "when argument is of %select{integer|floating point|complex}2 type">,
   InGroup<AbsoluteValue>;
 def note_replace_abs_function : Note<"use function '%0' instead">;
+def warn_pointer_abs : Warning<
+  "taking the absolute value of %select{pointer|function|array}0 type %1 is suspicious">,
+  InGroup<AbsoluteValue>;
 
 def warn_infinite_recursive_function : Warning<
   "all paths through this function will call itself">,
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 5c942273314..24940167be2 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -5085,6 +5085,19 @@ void Sema::CheckAbsoluteValueFunction(const CallExpr *Call,
     return;
   }
 
+  // Taking the absolute value of a pointer is very suspicious, they probably
+  // wanted to index into an array, dereference a pointer, call a function, etc.
+  if (ArgType->isPointerType() || ArgType->canDecayToPointerType()) {
+    unsigned DiagType = 0;
+    if (ArgType->isFunctionType())
+      DiagType = 1;
+    else if (ArgType->isArrayType())
+      DiagType = 2;
+
+    Diag(Call->getExprLoc(), diag::warn_pointer_abs) << DiagType << ArgType;
+    return;
+  }
+
   // std::abs has overloads which prevent most of the absolute value problems
   // from occurring.
   if (IsStdAbs)
diff --git a/clang/test/Sema/warn-absolute-value.c b/clang/test/Sema/warn-absolute-value.c
index 70601db63a1..109d515d3b2 100644
--- a/clang/test/Sema/warn-absolute-value.c
+++ b/clang/test/Sema/warn-absolute-value.c
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only -verify %s -Wabsolute-value
-// RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only %s -Wabsolute-value -fdiagnostics-parseable-fixits 2>&1 | FileCheck %s
+// RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only -verify %s -Wabsolute-value -Wno-int-conversion
+// RUN: %clang_cc1 -triple i686-pc-linux-gnu -fsyntax-only %s -Wabsolute-value -Wno-int-conversion -fdiagnostics-parseable-fixits 2>&1 | FileCheck %s
 
 int abs(int);
 long int labs(long int);
@@ -780,3 +780,19 @@ void test_unsigned_long(unsigned long x) {
   // CHECK: fix-it:"{{.*}}":{[[@LINE-3]]:9-[[@LINE-3]]:24}:""
 }
 
+long long test_array() {
+  return llabs((long long[]){1});
+  // expected-warning@-1 {{absolute value of array type}}
+}
+long long test_function_pointer() {
+  return llabs(&test_function_pointer);
+  // expected-warning@-1 {{absolute value of pointer type}}
+}
+long long test_void_pointer(void *x) {
+  return llabs(x);
+  // expected-warning@-1 {{absolute value of pointer type}}
+}
+long long test_function() {
+  return llabs(test_function);
+  // expected-warning@-1 {{absolute value of function type}}
+}