[Sema] Move some stuff into -Wtautological-unsigned-enum-zero-compare
Recommit. Original commit was reverted because buildbots broke.
The error was only reproducible in the build with assertions.
The problem was that the diagnostic expected true/false as
bool, while it was provided as string "true"/"false".
Summary:
As requested by Sam McCall:
> Enums (not new I guess). Typical case: if (enum < 0 || enum > MAX)
> The warning strongly suggests that the enum < 0 check has no effect
> (for enums with nonnegative ranges).
> Clang doesn't seem to optimize such checks out though, and they seem
> likely to catch bugs in some cases. Yes, only if there's UB elsewhere,
> but I assume not optimizing out these checks indicates a deliberate
> decision to stay somewhat compatible with a technically-incorrect
> mental model.
> If this is the case, should we move these to a
> -Wtautological-compare-enum subcategory?
Reviewers: rjmccall, rsmith, aaron.ballman, sammccall, bkramer, djasper
Reviewed By: aaron.ballman
Subscribers: jroelofs, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D37629
llvm-svn: 313745
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index 212fe65..87634ad 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -8583,7 +8583,7 @@
// bool values are handled by DiagnoseOutOfRangeComparison().
- BinaryOperatorKind op = E->getOpcode();
+ BinaryOperatorKind Op = E->getOpcode();
if (E->isValueDependent())
return false;
@@ -8592,22 +8592,26 @@
bool Match = true;
- 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();
+ if (Op == BO_LT && isNonBooleanUnsignedValue(LHS) && IsZero(S, RHS)) {
+ S.Diag(E->getOperatorLoc(),
+ HasEnumType(LHS) ? diag::warn_lunsigned_enum_always_true_comparison
+ : diag::warn_lunsigned_always_true_comparison)
+ << "< 0" << false << LHS->getSourceRange() << RHS->getSourceRange();
+ } else if (Op == BO_GE && isNonBooleanUnsignedValue(LHS) && IsZero(S, RHS)) {
+ S.Diag(E->getOperatorLoc(),
+ HasEnumType(LHS) ? diag::warn_lunsigned_enum_always_true_comparison
+ : diag::warn_lunsigned_always_true_comparison)
+ << ">= 0" << true << LHS->getSourceRange() << RHS->getSourceRange();
+ } else if (Op == BO_GT && isNonBooleanUnsignedValue(RHS) && IsZero(S, LHS)) {
+ S.Diag(E->getOperatorLoc(),
+ HasEnumType(RHS) ? diag::warn_runsigned_enum_always_true_comparison
+ : diag::warn_runsigned_always_true_comparison)
+ << "0 >" << false << LHS->getSourceRange() << RHS->getSourceRange();
+ } else if (Op == BO_LE && isNonBooleanUnsignedValue(RHS) && IsZero(S, LHS)) {
+ S.Diag(E->getOperatorLoc(),
+ HasEnumType(RHS) ? diag::warn_runsigned_enum_always_true_comparison
+ : diag::warn_runsigned_always_true_comparison)
+ << "0 <=" << true << LHS->getSourceRange() << RHS->getSourceRange();
} else
Match = false;