From 33e9203d936781748afcd6afa89207cb81420fd4 Mon Sep 17 00:00:00 2001 From: David Bolvansky Date: Tue, 24 Sep 2019 09:14:33 +0000 Subject: [PATCH] [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. git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@372708 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/clang/Basic/DiagnosticSemaKinds.td | 4 +- lib/Sema/SemaChecking.cpp | 47 ++++++++++------------ test/Sema/warn-int-in-bool-context.c | 20 +++++++-- 3 files changed, 39 insertions(+), 32 deletions(-) diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td index 9e00591c63..e7dacc852b 100644 --- a/include/clang/Basic/DiagnosticSemaKinds.td +++ b/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; + InGroup, DefaultIgnore; def warn_left_shift_in_bool_context : Warning< "converting the result of '<<' to a boolean; did you mean '(%0) != 0'?">, - InGroup; + InGroup, DefaultIgnore; def warn_logical_instead_of_bitwise : Warning< "use of logical '%0' with constant operand">, InGroup>; diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp index 19c83d6bac..59b875aed7 100644 --- a/lib/Sema/SemaChecking.cpp +++ b/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(E); + if (!IL) { + if (auto *UO = dyn_cast(E)) { + if (UO->getOpcode() == UO_Minus) + return dyn_cast(UO->getSubExpr()); + } + } + + return IL; +} + static void DiagnoseIntInBoolContext(Sema &S, Expr *E) { E = E->IgnoreParenImpCasts(); SourceLocation ExprLoc = E->getExprLoc(); if (const auto *BO = dyn_cast(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(E)) { - const auto *LHS = dyn_cast(CO->getTrueExpr()); - if (!LHS) { - if (auto *UO = dyn_cast(CO->getTrueExpr())) { - if (UO->getOpcode() == UO_Minus) - LHS = dyn_cast(UO->getSubExpr()); - if (!LHS) - return; - } else { - return; - } - } - - const auto *RHS = dyn_cast(CO->getFalseExpr()); - if (!RHS) { - if (auto *UO = dyn_cast(CO->getFalseExpr())) { - if (UO->getOpcode() == UO_Minus) - RHS = dyn_cast(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/test/Sema/warn-int-in-bool-context.c b/test/Sema/warn-int-in-bool-context.c index f190fdf6a1..ae35ca34fb 100644 --- a/test/Sema/warn-int-in-bool-context.c +++ b/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; -- 2.40.0