Sema: Handle C11 atomics when diagnosing out of range comparisons

This fixes a couple of asserts when analyzing comparisons involving
C11 atomics that were uncovered by r205608 when we extended the
applicability of -Wtautological-constant-out-of-range-compare.

llvm-svn: 213573

clang/lib/Sema/SemaChecking.cpp

@@ -4943,6 +4943,8 @@ struct IntRange {
       T = VT->getElementType().getTypePtr();
     if (const ComplexType *CT = dyn_cast<ComplexType>(T))
       T = CT->getElementType().getTypePtr();
+    if (const AtomicType *AT = dyn_cast<AtomicType>(T))
+      T = AT->getValueType().getTypePtr();
 
     // For enum types, use the known bit width of the enumerators.
     if (const EnumType *ET = dyn_cast<EnumType>(T)) {
@@ -4978,6 +4980,8 @@ struct IntRange {
       T = VT->getElementType().getTypePtr();
     if (const ComplexType *CT = dyn_cast<ComplexType>(T))
       T = CT->getElementType().getTypePtr();
+    if (const AtomicType *AT = dyn_cast<AtomicType>(T))
+      T = AT->getValueType().getTypePtr();
     if (const EnumType *ET = dyn_cast<EnumType>(T))
       T = C.getCanonicalType(ET->getDecl()->getIntegerType()).getTypePtr();
 
@@ -5380,6 +5384,8 @@ static void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E,
   // TODO: Investigate using GetExprRange() to get tighter bounds
   // on the bit ranges.
   QualType OtherT = Other->getType();
+  if (const AtomicType *AT = dyn_cast<AtomicType>(OtherT))
+    OtherT = AT->getValueType();
   IntRange OtherRange = IntRange::forValueOfType(S.Context, OtherT);
   unsigned OtherWidth = OtherRange.Width;
 

clang/test/Sema/atomic-compare.c

@@ -0,0 +1,21 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only
+
+void f(_Atomic(int) a, _Atomic(int) b) {
+  if (a > b)      {} // no warning
+  if (a < b)      {} // no warning
+  if (a >= b)     {} // no warning
+  if (a <= b)     {} // no warning
+  if (a == b)     {} // no warning
+  if (a != b)     {} // no warning
+
+  if (a == 0) {} // no warning
+  if (a > 0) {} // no warning
+  if (a > 1) {} // no warning
+  if (a > 2) {} // no warning
+
+  if (!a > 0) {}  // no warning
+  if (!a > 1)     {} // expected-warning {{comparison of constant 1 with boolean expression is always false}}
+  if (!a > 2)     {} // expected-warning {{comparison of constant 2 with boolean expression is always false}}
+  if (!a > b)     {} // no warning
+  if (!a > -1)    {} // expected-warning {{comparison of constant -1 with boolean expression is always true}}
+}

clang/test/Sema/atomic-expr.c

@@ -58,3 +58,6 @@ int func_13 (int x, unsigned y) {
   return x ? data1 : y;
 }
 
+int func_14 () {
+  return data1 == 0;
+}