Created attachment 10214 [details] C file that fails to compile with GCC Hello, I reported a bug on the GCC bugtracker (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81156) and it might have something to do with glibc, I am gonna copy & paste the original post here: Hey, I ran into some problems compiling code that contained a specific formula. I am using the type generic tgmath.h header because I am switching between float and double for performance testing reasons. If I include the tgmath.h header, the code doesn't compile, GCC ends up filling up all my RAM and doesn't succeed to compile the file. It compiles using the math.h header without a problem. Here's the code in question (also in the attachment): /* memory_leak.c */ #include <stdio.h> #include <stdlib.h> #include <tgmath.h> #ifdef TEST_SP typedef float test_float; #else typedef double test_float; #endif int main(int argc, char *argv[]) { int b = -1; test_float a, c, d, e, f, g, h, i; a = c = d = e = f = g = h = i = 1; a = 2*b/abs(b)*sqrt(pow(sqrt(pow(c, 2) - pow(d, 2)) - e*f*cos(g)*cos(h)/abs(b)*(i - 1), 2) + pow(d/2, 2)); return 0; } /* END */ Compile with: gcc -o memory_leak -DTEST_SP -std=c99 memory_leak.c -lm It ends up eating all the memory there is. Doesn't work on current GCC 7.1.1 on Arch nor on an RHEL6 distro with GCC 4.4.7. Works with GCC 5.3 in Cygwin. Clang and ICC compile without problems as well on Linux.
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81156#c1 for Joseph's analysis (combination explosion due to nested macros and repeated expansion).
This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU C Library master sources". The branch, master has been updated via d9bef9c0a41bc3ca4036542cbf2a7d2d0cf60237 (commit) from 988f991b5069f09d793c887618e84a196b100416 (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=d9bef9c0a41bc3ca4036542cbf2a7d2d0cf60237 commit d9bef9c0a41bc3ca4036542cbf2a7d2d0cf60237 Author: Joseph Myers <joseph@codesourcery.com> Date: Tue Aug 22 17:55:42 2017 +0000 Fix tgmath.h handling of complex integers (bug 21684). The tgmath.h macros return a real type not a complex type when an argument is of complex integer type (a GNU extension) and there are no arguments of complex floating type. It seems clear that just as real integers are mapped to double for tgmath.h, so complex integers should be mapped to _Complex double. This patch implements such a mapping. The main complication in fixing this bug is that the tgmath.h macros expand their arguments a large number of times, resulting in exponential blowup of the size of the expansion when calls to tgmath.h macros are used in the arguments of such macros; it would be unfortunate for fixing a bug with a fairly obscure extension to make the macros expand their arguments even more times. Thus, this patch optimizes the definitions of the relevant macros. __tgmath_real_type previously expanded its argument 7 times and now expands it 3 times. __tgmath_complex_type, used in place of __tgmath_real_type only for functions that might return either real or complex types, not for complex functions that always return real types or always return complex types, expands its argument 5 times. So the sizes of the macro expansions from nested macro calls are correspondingly reduced (remembering that each tgmath.h macro expands __tgmath_real_type, or sometimes now __tgmath_complex_type, several times). Sometimes the real return type resulted from calling a complex function and converting the result to a real type; sometimes it resulted from calling a real function, because the logic for determining whether arguments were real or complex, based on sizeof, was confused by integer promotions applying to e.g. short int but not _Complex short int. The relevant tests are converted to use a new macro __expr_is_real, which, by calling __builtin_classify_type rather than comparing the results of two calls to sizeof, also reduces the number of times macros expand their arguments. Although there are reductions in the number of times macros expand their arguments, I do not consider this to fix bug 21660, since a proper fix means each macro expanding its arguments only once (via using new compiler features designed for that purpose). Tested for x86_64. [BZ #21684] * math/tgmath.h (__floating_type): Simplify definitions. (__real_integer_type): New macro. (__complex_integer_type): Likewise. (__expr_is_real): Likewise. (__tgmath_real_type_sub): Update comment to describe handling of complex types. (__tgmath_complex_type_sub): New macro. (__tgmath_complex_type): Likewise. [__HAVE_FLOAT128 && __GLIBC_USE (IEC_60559_TYPES_EXT)] (__TGMATH_CF128): Use __expr_is_real. (__TGMATH_UNARY_REAL_IMAG): Use __tgmath_complex_type and __expr_is_real. (__TGMATH_BINARY_REAL_IMAG): Likewise. (__TGMATH_UNARY_REAL_IMAG_RET_REAL): Use __expr_is_real. * math/gen-tgmath-tests.py (Type.create_type): Create complex integer types. ----------------------------------------------------------------------- Summary of changes: ChangeLog | 20 +++++++ math/gen-tgmath-tests.py | 4 +- math/tgmath.h | 135 ++++++++++++++++++++++++++++++---------------- 3 files changed, 110 insertions(+), 49 deletions(-)
This is an automated email from the git hooks/post-receive script. It was generated because a ref change was pushed to the repository containing the project "GNU C Library master sources". The branch, master has been updated via be3a79a3cc8d8111811a52b0fe243b6f4dd03844 (commit) from 2e64ec9c9eac3aeb70f7cfa2392846c87c28068e (commit) Those revisions listed above that are new to this repository have not appeared on any other notification email; so we list those revisions in full, below. - Log ----------------------------------------------------------------- https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=be3a79a3cc8d8111811a52b0fe243b6f4dd03844 commit be3a79a3cc8d8111811a52b0fe243b6f4dd03844 Author: Joseph Myers <joseph@codesourcery.com> Date: Wed Nov 15 02:08:56 2017 +0000 Use __builtin_tgmath in tgmath.h with GCC 8 (bug 21660). GCC mainline now supports __builtin_tgmath to allow <tgmath.h> macro implementations that expand their arguments only once, so avoiding exponential blowup in the size of macro expansions when calls to those macros are nested in arguments to those macros. This patch makes glibc's tgmath.h support using __builtin_tgmath, as a much simpler and more efficient alternative to the existing implementation. (As a side effect, the new feature would make it much more practical to support decimal floating point in <tgmath.h> with new compilers; currently, libdfp does not provide a <tgmath.h> implementation, and making decimal arguments cause integer arguments to be considered of type _Decimal64 instead of double would have been very problematic in the old implementation.) Tested for x86_64 (with GCC mainline). [BZ #21660] * math/tgmath.h (__HAVE_BUILTIN_TGMATH): New macro. [__HAVE_BUILTIN_TGMATH] (__TG_F16_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TG_F32_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TG_F64_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TG_F128_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TG_F32X_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TG_F64X_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TG_F128X_ARG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_FUNCS): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_RCFUNCS): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_1): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_2): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_2STD): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_3): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_1C): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_2C): Likewise. (__tgml): Make conditional on [!__HAVE_BUILTIN_TGMATH]. (__floating_type): Likewise. (__real_integer_type): Likewise. (__complex_integer_type): Likewise. (__expr_is_real): Likewise. (__tgmath_real_type_sub): Likewise. (__tgmath_real_type): Likewise. (__tgmath_complex_type_sub): Likewise. (__tgmath_complex_type): Likewise. (__TGMATH_F128): Likewise. (__TGMATH_CF128): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_UNARY_REAL_ONLY): Define using new macros. [__HAVE_BUILTIN_TGMATH] (__TGMATH_UNARY_REAL_RET_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_BINARY_FIRST_REAL_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_BINARY_FIRST_REAL_STD_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_BINARY_REAL_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_BINARY_REAL_STD_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_BINARY_REAL_RET_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_TERNARY_FIRST_SECOND_REAL_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_TERNARY_REAL_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_TERNARY_FIRST_REAL_RET_ONLY): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_UNARY_REAL_IMAG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_UNARY_IMAG): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_UNARY_REAL_IMAG_RET_REAL): Likewise. [__HAVE_BUILTIN_TGMATH] (__TGMATH_BINARY_REAL_IMAG): Likewise. (__TGMATH_UNARY_REAL_IMAG_RET_REAL_SAME): New macro. (carg): Use __TGMATH_UNARY_REAL_IMAG_RET_REAL_SAME. (cimag): Likewise. (creal): Likewise. ----------------------------------------------------------------------- Summary of changes: ChangeLog | 55 +++++++++++++++ math/tgmath.h | 204 +++++++++++++++++++++++++++++++++++++++++---------------- 2 files changed, 202 insertions(+), 57 deletions(-)
Fixed for 2.27 (when used with GCC 8 or later).