[Bug c++/80328] New: With -ffloat-store std::array operator[] no longer cost-free
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80328
Bug ID: 80328
Summary: With -ffloat-store std::array operator[] no longer
cost-free
Product: gcc
Version: 6.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pavel.celba at ricardo dot com
Target Milestone: ---
Following code:
#include
#include
#include
#include
int main()
{
static const size_t numIters = 1u;
srand(static_cast(time(nullptr)));
// Simple type timing
float vec[3];
for (int i = 0; i < 3; ++i)
vec[i] = static_cast(rand());
clock_t simpleBegin = clock();
for (size_t iter = 0u; iter < numIters; ++iter)
for (int i = 0; i < 3; ++i)
vec[i] += vec[i];
clock_t simpleEnd = clock();
// Simple type timing
std::array vec2;
for (int i = 0; i < 3; ++i)
vec2[i] = static_cast(rand());
clock_t arrayBegin = clock();
for (size_t iter = 0u; iter < numIters; ++iter)
for (int i = 0; i < 3; ++i)
vec2[i] += vec2[i];
clock_t arrayEnd = clock();
// Suppress optimizing out whole computation
volatile float suppressOptimizingOut[3];
for (int i = 0; i < 3; ++i)
{
suppressOptimizingOut[i] = vec[i];
suppressOptimizingOut[i] = vec2[i];
}
(void)suppressOptimizingOut; // Must use the value to suppress unused warning
std::cout << "Simple case time: " << double(simpleEnd - simpleBegin) /
CLOCKS_PER_SEC << std::endl;
std::cout << "Array case time: " << double(arrayEnd - arrayBegin) /
CLOCKS_PER_SEC << std::endl;
}
Compile options: -Wall -std=c++11 -ffloat-store -O2 -o a.out source_file.cpp
There is really no reason too - shouldn't do any additional operations compared
to simple case after all optimizations.
[Bug c++/68669] New: -Wunused-variable is not correctly supressed by #pragmas
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68669
Bug ID: 68669
Summary: -Wunused-variable is not correctly supressed by
#pragmas
Product: gcc
Version: 5.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pavel.celba at ricardo dot com
Target Milestone: ---
The GCC version info:
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/rs-sync/compilers/gcc/5.1.0/sle11/libexec/gcc/x86_64-unknown-linux-gnu/5.1.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../configure --prefix=/rs-sync/compilers/gcc/5.1.0/sle11
--libdir=/rs-sync/compilers/gcc/5.1.0/sle11/lib64 --enable-lto
--enable-gold=yes --enable-ld=yes
--with-gmp-include=/rs-sync/compilers/gcc/5.1.0/sle11/include
--with-gmp-lib=/rs-sync/compilers/gcc/5.1.0/sle11/lib64
--with-mpfr-include=/rs-sync/compilers/gcc/5.1.0/sle11/include
--with-mpfr-lib=/rs-sync/compilers/gcc/5.1.0/sle11/lib64
--with-mpc-include=/rs-sync/compilers/gcc/5.1.0/sle11/include
--with-mpc-lib=/rs-sync/compilers/gcc/5.1.0/sle11/lib64
--with-ppl-include=/rs-sync/compilers/gcc/5.1.0/sle11/include
--with-ppl-lib=/rs-sync/compilers/gcc/5.1.0/sle11/lib64
Thread model: posix
gcc version 5.1.0 (GCC)
Including following file from the boost unit test framework - boost version
1.58.0:
#include
and trying to supress unused-variable warnings still produce unused variable
warnings:
#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-variable"
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
#pragma GCC diagnostic ignored "-Wsign-compare"
#endif
#include
#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif
E.g. from our company unit test code compilation:
In file included from
/store/prtc-rsfile/pc1/pc1PlasticLinux/boost/1.58.0/boost/test/unit_test_log.hpp:28:0,
from
/store/prtc-rsfile/pc1/pc1PlasticLinux/boost/1.58.0/boost/test/test_tools.hpp:20,
from
/store/prtc-rsfile/pc1/pc1PlasticLinux/boost/1.58.0/boost/test/unit_test.hpp:19,
from
/store/prtc-rsfile/pc1/pc1PlasticLinux/cpputils/code/unitTest/../include/cuBoostUnitTestHeaderInclude.h:20,
from
/store/prtc-rsfile/pc1/pc1PlasticLinux/cpputils/code/unitTest/src/run_tests.cpp:2:
/store/prtc-rsfile/pc1/pc1PlasticLinux/boost/1.58.0/boost/test/unit_test_log.hpp:134:28:
warning: âboost::unit_test::{anonymous}::unit_test_logâ defined but not used
[-Wunused-variable]
BOOST_TEST_SINGLETON_INST( unit_test_log )
^
/store/prtc-rsfile/pc1/pc1PlasticLinux/boost/1.58.0/boost/test/utils/trivial_singleton.hpp:64:36:
note: in definition of macro âBOOST_TEST_SINGLETON_INSTâ
namespace { BOOST_JOIN( inst, _t)& inst = BOOST_JOIN( inst, _t)::instance(); }
FYI - run_tests.cpp is exactly this:
#define BOOST_TEST_MODULE cpputils_tests test
#include "cuBoostUnitTestHeaderInclude.h"
[Bug c++/68669] -Wunused-variable is not correctly supressed by #pragmas
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68669 --- Comment #2 from Pavel Celba --- Created attachment 36893 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36893&action=edit Preprocessed run_tests.cpp Added the pre-processed run_tests.cpp
[Bug c++/103096] New: Compiling never ends (at least not in resonable time - less than 10 mins)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103096
Bug ID: 103096
Summary: Compiling never ends (at least not in resonable time -
less than 10 mins)
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pavel.celba at ricardo dot com
Target Milestone: ---
Code - file test.cpp:
#include
#include
using namespace std;
template int qHash(const T& a)
{
return qHash(std::pair(a, a));
}
int main()
{
int a = 3;
std::cout << qHash(a);
}
Run as normally:
gcc test.cpp
[Bug libstdc++/103096] Compiling never ends (at least not in resonable time - less than 10 mins)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103096 --- Comment #2 from Pavel Celba --- But shouldn't the compiler end in all cases with some error? There should be a depth instantiation limit which is reached and compilation ended. No matter how non-sensible the input is. My input is quite sensible C++ code bug thing any amateur can easily do.
