Author: Youngsuk Kim Date: 2024-05-17T09:29:20-04:00 New Revision: f39af73f3edcc949bf9dc3535effc59afbcdda22
URL: https://github.com/llvm/llvm-project/commit/f39af73f3edcc949bf9dc3535effc59afbcdda22 DIFF: https://github.com/llvm/llvm-project/commit/f39af73f3edcc949bf9dc3535effc59afbcdda22.diff LOG: [clang][Sema] Warn consecutive builtin comparisons in an expression (#92200) Add warning under `-Wparentheses` for consistency with `gcc 14.1`. Closes #20456 --------- Co-authored-by: Aaron Ballman <aa...@aaronballman.com> Added: Modified: clang/docs/ReleaseNotes.rst clang/include/clang/Basic/DiagnosticSemaKinds.td clang/lib/Sema/SemaExpr.cpp clang/test/Sema/bool-compare.c clang/test/Sema/parentheses.cpp clang/test/SemaCXX/bool-compare.cpp clang/test/SemaCXX/cxx2a-adl-only-template-id.cpp clang/test/SemaTemplate/typo-dependent-name.cpp clang/test/SemaTemplate/typo-template-name.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 9799f878d7d72..85327576548cf 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -498,6 +498,9 @@ Improvements to Clang's diagnostics } }; +- Clang emits a ``-Wparentheses`` warning for expressions with consecutive comparisons like ``x < y < z``. + Fixes #GH20456. + Improvements to Clang's time-trace ---------------------------------- diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td index 59f44bc26eaf2..09b1874f9fddd 100644 --- a/clang/include/clang/Basic/DiagnosticSemaKinds.td +++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td @@ -6919,6 +6919,10 @@ def warn_precedence_bitwise_conditional : Warning< def note_precedence_conditional_first : Note< "place parentheses around the '?:' expression to evaluate it first">; +def warn_consecutive_comparison : Warning< + "comparisons like 'X<=Y<=Z' don't have their mathematical meaning">, + InGroup<Parentheses>; + def warn_enum_constant_in_bool_context : Warning< "converting the enum constant to a boolean">, InGroup<IntInBoolContext>, DefaultIgnore; diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp index e0aae6333e1a1..5ecfdee21f09d 100644 --- a/clang/lib/Sema/SemaExpr.cpp +++ b/clang/lib/Sema/SemaExpr.cpp @@ -14867,6 +14867,11 @@ ExprResult Sema::CreateBuiltinBinOp(SourceLocation OpLoc, case BO_GT: ConvertHalfVec = true; ResultTy = CheckCompareOperands(LHS, RHS, OpLoc, Opc); + + if (const auto *BI = dyn_cast<BinaryOperator>(LHSExpr); + BI && BI->isComparisonOp()) + Diag(OpLoc, diag::warn_consecutive_comparison); + break; case BO_EQ: case BO_NE: diff --git a/clang/test/Sema/bool-compare.c b/clang/test/Sema/bool-compare.c index 923ff4208e8be..2308dc4bf2bb2 100644 --- a/clang/test/Sema/bool-compare.c +++ b/clang/test/Sema/bool-compare.c @@ -85,7 +85,7 @@ void f(int x, int y, int z) { if ((a<y) != -1) {}// expected-warning {{comparison of constant -1 with boolean expression is always true}} if ((a<y) == z) {} // no warning - if (a>y<z) {} // no warning + if (a>y<z) {} // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} if ((a<y) > z) {} // no warning if((a<y)>(z<y)) {} // no warning if((a<y)==(z<y)){} // no warning @@ -145,7 +145,7 @@ void f(int x, int y, int z) { if (-1 !=(a<y)) {} // expected-warning {{comparison of constant -1 with boolean expression is always true}} if (z ==(a<y)) {} // no warning - if (z<a>y) {} // no warning + if (z<a>y) {} // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} if (z > (a<y)) {} // no warning if((z<y)>(a<y)) {} // no warning if((z<y)==(a<y)){} // no warning diff --git a/clang/test/Sema/parentheses.cpp b/clang/test/Sema/parentheses.cpp index 324d9b5f1e414..e991cee16b0e2 100644 --- a/clang/test/Sema/parentheses.cpp +++ b/clang/test/Sema/parentheses.cpp @@ -215,3 +215,14 @@ namespace PR20735 { // fix-it:"{{.*}}":{[[@LINE-9]]:20-[[@LINE-9]]:20}:")" } } + +void consecutive_builtin_compare(int x, int y, int z) { + (void)(x < y < z); // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} + (void)(x < y > z); // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} + (void)(x < y <= z); // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} + (void)(x <= y > z); // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} + (void)((x < y) < z); // no-warning + (void)((x < y) >= z); // no-warning + + // TODO: Also issue warning for consecutive comparisons that use overloaded comparison operators? +} diff --git a/clang/test/SemaCXX/bool-compare.cpp b/clang/test/SemaCXX/bool-compare.cpp index fe47633bb23b6..4e33e076a7de4 100644 --- a/clang/test/SemaCXX/bool-compare.cpp +++ b/clang/test/SemaCXX/bool-compare.cpp @@ -98,7 +98,7 @@ void f(int x, int y, int z) { if ((a<y) != -1) {}// expected-warning {{comparison of constant -1 with expression of type 'bool' is always true}} if ((a<y) == z) {} // no warning - if (a>y<z) {} // no warning + if (a>y<z) {} // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} if ((a<y) > z) {} // no warning if((a<y)>(z<y)) {} // no warning if((a<y)==(z<y)){} // no warning @@ -159,7 +159,7 @@ void f(int x, int y, int z) { if (-1 !=(a<y)) {} // expected-warning {{comparison of constant -1 with expression of type 'bool' is always true}} if (z ==(a<y)) {} // no warning - if (z<a>y) {} // no warning + if (z<a>y) {} // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} if (z > (a<y)) {} // no warning if((z<y)>(a<y)) {} // no warning if((z<y)==(a<y)){} // no warning diff --git a/clang/test/SemaCXX/cxx2a-adl-only-template-id.cpp b/clang/test/SemaCXX/cxx2a-adl-only-template-id.cpp index 28ecbade1b1a9..b8397f41febc3 100644 --- a/clang/test/SemaCXX/cxx2a-adl-only-template-id.cpp +++ b/clang/test/SemaCXX/cxx2a-adl-only-template-id.cpp @@ -27,7 +27,7 @@ int e = h<0>(q); // ok, found by unqualified lookup void fn() { f<0>(q); int f; - f<0>(q); // expected-error {{invalid operands to binary expression}} + f<0>(q); // expected-error {{invalid operands to binary expression}} // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} } void disambig() { diff --git a/clang/test/SemaTemplate/typo-dependent-name.cpp b/clang/test/SemaTemplate/typo-dependent-name.cpp index 88b2fc373b1f5..fb61b03e50109 100644 --- a/clang/test/SemaTemplate/typo-dependent-name.cpp +++ b/clang/test/SemaTemplate/typo-dependent-name.cpp @@ -20,11 +20,11 @@ struct X : Base<T> { bool f(T other) { // A pair of comparisons; 'inner' is a dependent name so can't be assumed // to be a template. - return this->inner < other > ::z; + return this->inner < other > ::z; // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} } }; -void use_x(X<int> x) { x.f(0); } +void use_x(X<int> x) { x.f(0); } // expected-note {{requested here}} template<typename T> struct Y { diff --git a/clang/test/SemaTemplate/typo-template-name.cpp b/clang/test/SemaTemplate/typo-template-name.cpp index fe5201a8e26c3..741aa708e81fc 100644 --- a/clang/test/SemaTemplate/typo-template-name.cpp +++ b/clang/test/SemaTemplate/typo-template-name.cpp @@ -36,7 +36,7 @@ namespace InExpr { // These are valid expressions. foo<foo; // expected-warning {{self-comparison}} - foo<int()>(0); + foo<int()>(0); // expected-warning {{comparisons like 'X<=Y<=Z' don't have their mathematical meaning}} foo<int(), true>(false); foo<Base{}.n; } _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
