[Diagnostics] Do not diagnose unsigned shifts in boolean context (-Wint-in-bool-context)

I was looking at old GCC's patch. Current "trunk" version avoids warning for unsigned case, GCC warns only for signed shifts.

llvm-svn: 372708

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 9e00591..e7dacc8 100644 (file)
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5722,10 +5722,10 @@ def note_precedence_conditional_first : Note<
 
 def warn_enum_constant_in_bool_context : Warning<
   "converting the enum constant to a boolean">,
-  InGroup<IntInBoolContext>;
+  InGroup<IntInBoolContext>, DefaultIgnore;
 def warn_left_shift_in_bool_context : Warning<
   "converting the result of '<<' to a boolean; did you mean '(%0) != 0'?">,
-  InGroup<IntInBoolContext>;
+  InGroup<IntInBoolContext>, DefaultIgnore;
 def warn_logical_instead_of_bitwise : Warning<
   "use of logical '%0' with constant operand">,
   InGroup<DiagGroup<"constant-logical-operand">>;

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 19c83d6..59b875a 100644 (file)
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -11296,44 +11296,39 @@ static bool isSameWidthConstantConversion(Sema &S, Expr *E, QualType T,
   return true;
 }
 
+static const IntegerLiteral *getIntegerLiteral(Expr *E) {
+  const auto *IL = dyn_cast<IntegerLiteral>(E);
+  if (!IL) {
+    if (auto *UO = dyn_cast<UnaryOperator>(E)) {
+      if (UO->getOpcode() == UO_Minus)
+        return dyn_cast<IntegerLiteral>(UO->getSubExpr());
+    }
+  }
+
+  return IL;
+}
+
 static void DiagnoseIntInBoolContext(Sema &S, Expr *E) {
   E = E->IgnoreParenImpCasts();
   SourceLocation ExprLoc = E->getExprLoc();
 
   if (const auto *BO = dyn_cast<BinaryOperator>(E)) {
     BinaryOperator::Opcode Opc = BO->getOpcode();
-    if (Opc == BO_Shl)
+    // Do not diagnose unsigned shifts.
+    if (Opc == BO_Shl && E->getType()->isSignedIntegerType())
       S.Diag(ExprLoc, diag::warn_left_shift_in_bool_context) << E;
   }
 
   if (const auto *CO = dyn_cast<ConditionalOperator>(E)) {
-    const auto *LHS = dyn_cast<IntegerLiteral>(CO->getTrueExpr());
-    if (!LHS) {
-      if (auto *UO = dyn_cast<UnaryOperator>(CO->getTrueExpr())) {
-        if (UO->getOpcode() == UO_Minus)
-          LHS = dyn_cast<IntegerLiteral>(UO->getSubExpr());
-        if (!LHS)
-          return;
-      } else {
-        return;
-      }
-    }
-
-    const auto *RHS = dyn_cast<IntegerLiteral>(CO->getFalseExpr());
-    if (!RHS) {
-      if (auto *UO = dyn_cast<UnaryOperator>(CO->getFalseExpr())) {
-        if (UO->getOpcode() == UO_Minus)
-          RHS = dyn_cast<IntegerLiteral>(UO->getSubExpr());
-        if (!RHS)
-          return;
-      } else {
-        return;
-      }
-    }
-
+    const auto *LHS = getIntegerLiteral(CO->getTrueExpr());
+    if (!LHS)
+      return;
+    const auto *RHS = getIntegerLiteral(CO->getFalseExpr());
+    if (!RHS)
+      return;
     if ((LHS->getValue() == 0 || LHS->getValue() == 1) &&
         (RHS->getValue() == 0 || RHS->getValue() == 1))
-      // Do not diagnose common idioms
+      // Do not diagnose common idioms.
       return;
     if (LHS->getValue() != 0 && LHS->getValue() != 0)
       S.Diag(ExprLoc, diag::warn_integer_constants_in_conditional_always_true);

diff --git a/clang/test/Sema/warn-int-in-bool-context.c b/clang/test/Sema/warn-int-in-bool-context.c
index f190fdf..ae35ca3 100644 (file)
--- a/clang/test/Sema/warn-int-in-bool-context.c
+++ b/clang/test/Sema/warn-int-in-bool-context.c
@@ -7,6 +7,8 @@
 #define TWO 2
 
 #define SHIFT(l, r) l << r
+#define MM a << a
+#define AF 1 << 7
 
 #ifdef __cplusplus
 typedef bool boolean;
@@ -20,15 +22,25 @@ enum num {
   two,
 };
 
-int test(int a, enum num n) {
+int test(int a, unsigned b, enum num n) {
   boolean r;
-  r = (1 << 3); // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << 3) != 0'?}}
-  r = TWO << 7; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << 7) != 0'?}}
+  r = a << a; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(a << a) != 0'?}}
+  r = MM; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(a << a) != 0'?}}
+  r = (1 << 7); // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << 7) != 0'?}}
+  r = 2UL << 2;
+  r = 2 << b; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << b) != 0'?}}
+  r = (unsigned)(2 << b); 
+  r = b << 7;
+  r = (1 << a); // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << a) != 0'?}}
+  r = TWO << a; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << a) != 0'?}}
   r = a << 7;   // expected-warning {{converting the result of '<<' to a boolean; did you mean '(a << 7) != 0'?}}
   r = ONE << a; // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << a) != 0'?}}
-  if (TWO << 4) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << 4) != 0'?}}
+  if (TWO << a) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(2 << a) != 0'?}}
     return a;
 
+  for (a = 0; 1 << a; a++) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(1 << a) != 0'?}}
+    ; 
+
   if (a << TWO) // expected-warning {{converting the result of '<<' to a boolean; did you mean '(a << 2) != 0'?}}
     return a;