lebedev.ri updated this revision to Diff 114396.
lebedev.ri added a comment.
And finish reducing the code by for-range-loop`ing over array + use
`std::array`.
Repository:
rL LLVM
https://reviews.llvm.org/D37629
Files:
include/clang/Basic/DiagnosticGroups.td
include/clang/Basic/DiagnosticSemaKinds.td
lib/Sema/SemaChecking.cpp
test/Sema/compare.c
test/Sema/tautological-unsigned-enum-zero-compare.c
Index: test/Sema/tautological-unsigned-enum-zero-compare.c
===================================================================
--- /dev/null
+++ test/Sema/tautological-unsigned-enum-zero-compare.c
@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -fsyntax-only -DTEST -verify %s
+// RUN: %clang_cc1 -fsyntax-only -Wno-tautological-unsigned-enum-zero-compare -verify %s
+
+int main() {
+ enum A { A_foo, A_bar };
+ enum A a;
+
+#ifdef TEST
+ if (a < 0) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
+ return 0;
+ if (a >= 0) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
+ return 0;
+ if (0 <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
+ return 0;
+ if (0 > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
+ return 0;
+ if (a < 0U) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
+ return 0;
+ if (a >= 0U) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
+ return 0;
+ if (0U <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
+ return 0;
+ if (0U > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
+ return 0;
+#else
+ // expected-no-diagnostics
+ if (a < 0)
+ return 0;
+ if (a >= 0)
+ return 0;
+ if (0 <= a)
+ return 0;
+ if (0 > a)
+ return 0;
+ if (a < 0U)
+ return 0;
+ if (a >= 0U)
+ return 0;
+ if (0U <= a)
+ return 0;
+ if (0U > a)
+ return 0;
+#endif
+
+ return 1;
+}
Index: test/Sema/compare.c
===================================================================
--- test/Sema/compare.c
+++ test/Sema/compare.c
@@ -308,8 +308,59 @@
int rdar8511238() {
enum A { A_foo, A_bar };
enum A a;
+
+ if (a == 0)
+ return 0;
+ if (a != 0)
+ return 0;
if (a < 0) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
- return 0;
+ return 0;
+ if (a <= 0)
+ return 0;
+ if (a > 0)
+ return 0;
+ if (a >= 0) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
+ return 0;
+
+ if (0 == a)
+ return 0;
+ if (0 != a)
+ return 0;
+ if (0 < a)
+ return 0;
+ if (0 <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
+ return 0;
+ if (0 > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
+ return 0;
+ if (0 >= a)
+ return 0;
+
+ if (a == 0U)
+ return 0;
+ if (a != 0U)
+ return 0;
+ if (a < 0U) // expected-warning {{comparison of unsigned enum expression < 0 is always false}}
+ return 0;
+ if (a <= 0U)
+ return 0;
+ if (a > 0U)
+ return 0;
+ if (a >= 0U) // expected-warning {{comparison of unsigned enum expression >= 0 is always true}}
+ return 0;
+
+ if (0U == a)
+ return 0;
+ if (0U != a)
+ return 0;
+ if (0U < a)
+ return 0;
+ if (0U <= a) // expected-warning {{comparison of 0 <= unsigned enum expression is always true}}
+ return 0;
+ if (0U > a) // expected-warning {{comparison of 0 > unsigned enum expression is always false}}
+ return 0;
+ if (0U >= a)
+ return 0;
+
return 20;
}
Index: lib/Sema/SemaChecking.cpp
===================================================================
--- lib/Sema/SemaChecking.cpp
+++ lib/Sema/SemaChecking.cpp
@@ -8583,35 +8583,69 @@
// bool values are handled by DiagnoseOutOfRangeComparison().
- BinaryOperatorKind op = E->getOpcode();
if (E->isValueDependent())
return false;
Expr *LHS = E->getLHS();
Expr *RHS = E->getRHS();
- bool Match = true;
+ enum IsEnum { False = false, True = true, SizeOfIsEnum };
+ struct TautologicalComparison {
+ Expr *&Value;
+ BinaryOperatorKind op;
+ Expr *&Const;
+ std::array<unsigned, SizeOfIsEnum> DiagID;
+ const char *cmp;
+ bool Result;
+ };
- if (op == BO_LT && isNonBooleanUnsignedValue(LHS) && IsZero(S, RHS)) {
- S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
- << "< 0" << "false" << HasEnumType(LHS)
- << LHS->getSourceRange() << RHS->getSourceRange();
- } else if (op == BO_GE && isNonBooleanUnsignedValue(LHS) && IsZero(S, RHS)) {
- S.Diag(E->getOperatorLoc(), diag::warn_lunsigned_always_true_comparison)
- << ">= 0" << "true" << HasEnumType(LHS)
- << LHS->getSourceRange() << RHS->getSourceRange();
- } else if (op == BO_GT && isNonBooleanUnsignedValue(RHS) && IsZero(S, LHS)) {
- S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
- << "0 >" << "false" << HasEnumType(RHS)
- << LHS->getSourceRange() << RHS->getSourceRange();
- } else if (op == BO_LE && isNonBooleanUnsignedValue(RHS) && IsZero(S, LHS)) {
- S.Diag(E->getOperatorLoc(), diag::warn_runsigned_always_true_comparison)
- << "0 <=" << "true" << HasEnumType(RHS)
- << LHS->getSourceRange() << RHS->getSourceRange();
- } else
- Match = false;
+ const std::array<const TautologicalComparison, 4> TautologicalComparisons = {{
+ {LHS,
+ BO_LT,
+ RHS,
+ {{diag::warn_lunsigned_always_true_comparison,
+ diag::warn_lunsigned_enum_always_true_comparison}},
+ "< 0",
+ false},
+ {LHS,
+ BO_GE,
+ RHS,
+ {{diag::warn_lunsigned_always_true_comparison,
+ diag::warn_lunsigned_enum_always_true_comparison}},
+ ">= 0",
+ true},
+ {RHS,
+ BO_GT,
+ LHS,
+ {{diag::warn_runsigned_always_true_comparison,
+ diag::warn_runsigned_enum_always_true_comparison}},
+ "0 >",
+ false},
+ {RHS,
+ BO_LE,
+ LHS,
+ {{diag::warn_runsigned_always_true_comparison,
+ diag::warn_runsigned_enum_always_true_comparison}},
+ "0 <=",
+ true},
+ }};
- return Match;
+ BinaryOperatorKind op = E->getOpcode();
+ for (const TautologicalComparison &Check : TautologicalComparisons) {
+ if (Check.op != op)
+ continue;
+
+ if (!(isNonBooleanUnsignedValue(Check.Value) && IsZero(S, Check.Const)))
+ return false;
+
+ S.Diag(E->getOperatorLoc(), Check.DiagID[HasEnumType(Check.Value)])
+ << Check.cmp << Check.Result << LHS->getSourceRange()
+ << RHS->getSourceRange();
+
+ return true;
+ }
+
+ return false;
}
void DiagnoseOutOfRangeComparison(Sema &S, BinaryOperator *E, Expr *Constant,
Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td
+++ include/clang/Basic/DiagnosticSemaKinds.td
@@ -5893,19 +5893,26 @@
"%select{non-|}1static data member %2 declared const here|"
"member function %q1 is declared const here}0">;
+def warn_lunsigned_always_true_comparison : Warning<
+ "comparison of unsigned expression %0 is always %select{false|true}1">,
+ InGroup<TautologicalUnsignedZeroCompare>;
+def warn_runsigned_always_true_comparison : Warning<
+ "comparison of %0 unsigned expression is always %select{false|true}1">,
+ InGroup<TautologicalUnsignedZeroCompare>;
+def warn_lunsigned_enum_always_true_comparison : Warning<
+ "comparison of unsigned enum expression %0 is always %select{false|true}1">,
+ InGroup<TautologicalUnsignedEnumZeroCompare>;
+def warn_runsigned_enum_always_true_comparison : Warning<
+ "comparison of %0 unsigned enum expression is always %select{false|true}1">,
+ InGroup<TautologicalUnsignedEnumZeroCompare>;
+
def warn_mixed_sign_comparison : Warning<
"comparison of integers of different signs: %0 and %1">,
InGroup<SignCompare>, DefaultIgnore;
-def warn_lunsigned_always_true_comparison : Warning<
- "comparison of unsigned%select{| enum}2 expression %0 is always %1">,
- InGroup<TautologicalUnsignedZeroCompare>;
def warn_out_of_range_compare : Warning<
"comparison of %select{constant %0|true|false}1 with "
"%select{expression of type %2|boolean expression}3 is always "
"%select{false|true}4">, InGroup<TautologicalOutOfRangeCompare>;
-def warn_runsigned_always_true_comparison : Warning<
- "comparison of %0 unsigned%select{| enum}2 expression is always %1">,
- InGroup<TautologicalUnsignedZeroCompare>;
def warn_comparison_of_mixed_enum_types : Warning<
"comparison of two values with different enumeration types"
"%diff{ ($ and $)|}0,1">,
Index: include/clang/Basic/DiagnosticGroups.td
===================================================================
--- include/clang/Basic/DiagnosticGroups.td
+++ include/clang/Basic/DiagnosticGroups.td
@@ -428,6 +428,7 @@
def StringPlusChar : DiagGroup<"string-plus-char">;
def StrncatSize : DiagGroup<"strncat-size">;
def TautologicalUnsignedZeroCompare : DiagGroup<"tautological-unsigned-zero-compare">;
+def TautologicalUnsignedEnumZeroCompare : DiagGroup<"tautological-unsigned-enum-zero-compare">;
def TautologicalOutOfRangeCompare : DiagGroup<"tautological-constant-out-of-range-compare">;
def TautologicalPointerCompare : DiagGroup<"tautological-pointer-compare">;
def TautologicalOverlapCompare : DiagGroup<"tautological-overlap-compare">;
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