My fix for bug 111059 and bug 111911 caused a conversion of a floating constant to boolean to wrongly no longer be considered an integer constant expression, because logic to insert a NOP_EXPR in c_objc_common_truthvalue_conversion for an argument not an integer constant expression itself now took place after rather than before the conversion to bool. In the specific case of casting a floating constant to bool, the result is an integer constant expression even though the argument isn't (build_c_cast deals with ensuring that casts to integer type of anything of floating type more complicated than a single floating constant don't get wrongly treated as integer constant expressions even if they fold to constants), so fix the logic in c_objc_common_truthvalue_conversion to handle that special case.
Bootstrapped with no regressions for x86_64-pc-linux-gnu. PR c/113776 gcc/c * c-typeck.cc (c_objc_common_truthvalue_conversion): Return an integer constant expression for boolean conversion of floating constant. gcc/testsuite/ * gcc.dg/pr113776-1.c, gcc.dg/pr113776-2.c, gcc.dg/pr113776-3.c, gcc.dg/pr113776-4.c: New tests. --- Applied to mainline. The original commit this is fixing has only gone on mainline so far; any backports of that original commit will need to take care to include this fix (and adjust for GCC 13 branch not having -std=c23 and older versions not having enums with fixed underlying type). diff --git a/gcc/c/c-typeck.cc b/gcc/c/c-typeck.cc index 3b519c48ae0..ddeab1e2a8a 100644 --- a/gcc/c/c-typeck.cc +++ b/gcc/c/c-typeck.cc @@ -13572,7 +13572,17 @@ c_objc_common_truthvalue_conversion (location_t location, tree expr, tree type) break; } - int_const = (TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr)); + /* Conversion of a floating constant to boolean goes through here + and yields an integer constant expression. Otherwise, the result + is only an integer constant expression if the argument is. */ + int_const = ((TREE_CODE (expr) == INTEGER_CST && !TREE_OVERFLOW (expr)) + || ((TREE_CODE (expr) == REAL_CST + || TREE_CODE (expr) == COMPLEX_CST) + && (TREE_CODE (type) == BOOLEAN_TYPE + || (TREE_CODE (type) == ENUMERAL_TYPE + && ENUM_UNDERLYING_TYPE (type) != NULL_TREE + && (TREE_CODE (ENUM_UNDERLYING_TYPE (type)) + == BOOLEAN_TYPE))))); int_operands = EXPR_INT_CONST_OPERANDS (expr); if (int_operands && TREE_CODE (expr) != INTEGER_CST) { diff --git a/gcc/testsuite/gcc.dg/pr113776-1.c b/gcc/testsuite/gcc.dg/pr113776-1.c new file mode 100644 index 00000000000..36190fbc3fe --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr113776-1.c @@ -0,0 +1,5 @@ +/* { dg-do compile } */ +/* { dg-options "-std=c11 -pedantic" } */ + +char d[(_Bool)0.5 == 1 ? 1 : -1]; +char f[(_Bool)0.0 == 0 ? 1 : -1]; diff --git a/gcc/testsuite/gcc.dg/pr113776-2.c b/gcc/testsuite/gcc.dg/pr113776-2.c new file mode 100644 index 00000000000..9e88210892a --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr113776-2.c @@ -0,0 +1,4 @@ +/* { dg-do compile } */ +/* { dg-options "-std=c11 -pedantic" } */ + +enum e { A = (_Bool) 0.0, B = (_Bool) 0.5, C = (_Bool) 1.0 }; diff --git a/gcc/testsuite/gcc.dg/pr113776-3.c b/gcc/testsuite/gcc.dg/pr113776-3.c new file mode 100644 index 00000000000..c615994a89f --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr113776-3.c @@ -0,0 +1,7 @@ +/* { dg-do compile } */ +/* { dg-options "-std=c23 -pedantic" } */ + +enum ebool : bool { BF, BT }; + +char d[(enum ebool)0.5 == 1 ? 1 : -1]; +char f[(enum ebool)0.0 == 0 ? 1 : -1]; diff --git a/gcc/testsuite/gcc.dg/pr113776-4.c b/gcc/testsuite/gcc.dg/pr113776-4.c new file mode 100644 index 00000000000..1b57557746e --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr113776-4.c @@ -0,0 +1,6 @@ +/* { dg-do compile } */ +/* { dg-options "-std=c23 -pedantic" } */ + +enum ebool : bool { BF, BT }; + +enum e { A = (enum ebool) 0.0, B = (enum ebool) 0.5, C = (enum ebool) 1.0 }; -- Joseph S. Myers josmy...@redhat.com