GCC 9.1

On May 3, the first public release of the ninth version of GCC took place: GCC 9.1.
It contains many significant improvements and additions compared to the eighth
version.

General changes

Options

• Commands that accept size now support 64-bit values ​​and suffixes to specify size;
• Added option -flive-patching,to control optimizations that are potentially destructive to dynamic,code replacement;
• Added --completion option to support auto-completion in the command shell;
• Compiler diagnostics now include line numbers (-fno-diagnostics-show-line-numbers) and
  type information (fno-diagnostics-show-labels);
• Added option -fdiagnostics-format=json to output diagnostics in JSON format;
• Options for specifying alignment (-falign-functions, for example) can now accept a couple of alignment options;
• Added options for filtering the list of files (-fprofile-filter-files, -fprofile-exclude-files), which are instrumented by the profiler;
• AddressSanitizer now uses more compact alignment to catch invalid accesses to variables on the stack;
• Numerous output improvements -fopt-info;
• Added option -fsave-optimization-record to save the optimization report to a file;
• Added option -fipa-stack-alignment и -fipa-reference-addressable.

New built-in features

• __builtin_expect_with_probability;
• __builtin_has_attribute;
• __builtin_speculation_safe_value.

New attribute

• copy.

Other

Numerous code generation improvements related to:

• generation of switch constructs;
• inter-procedural optimizations;
• optimization based on profiling information;
• optimization at the assembly stage (LTO);

Also gcov's internal format is now JSON, and the new option --use-hotness-colors involves coloring lines of code based on how often they are used.

Languages

Quality and completeness of implementation OpenACC the languages ​​C, C++, and Fortran continue to improve.

C-like languages

• Partial support for OpenMP 5.0 has been implemented;
• Feature added __builtin_convertvector;
• Added warning -Waddress-of-packed-member;
• Improvements to a number of existing warnings;
• The error text when passing the wrong number of arguments to a macro now includes the declaration of the macro itself;
• Improvements to typo correction suggestions.

C

• Support _Static_assert with one argument for -std=c2x (future C standard);
• New warning -Wabsolute-value, which catches the wrong argument type for functions like abs().

C++

• New warnings: -Wdeprecated-copy,
  -Winit-list-lifetime,
  -Wredundant-move,
  -Wpessimizing-move,
  -Wclass-conversion;
• Work is underway to implement new features from the future standard C++2a;
• The frontend now stores more accurate information about a number of source code elements, which allows you to display more detailed information in diagnostics;
• Improved diagnostics for overloaded functions, binary operators, function calls and format strings;
• Added automatic fixes supported by some development environments for a number of popular errors (missing parentheses, namespaces, typos, etc.).

libstdc ++

• The C++17 implementation is no longer experimental;
• Added parallel algorithms, , , A no longer requires -lstdc++fs;
• Improved experimental support for C++2a ( , , std::bind_front, etc.);
• Support for opening file streams on Windows whose paths contain non-char characters;
• Initial support on Windows;
• Initial support for Networking TS.

D

D language version 2.076 is included in GCC.

Fortran

• Full support for asynchronous I/O;
• Implemented BACK argument for MINLOC and MAXLOC;
• Implemented FINDLOC and IS_CONTIGOUS functions;
• The syntax for accessing the components of complex numbers has been implemented: c%re and c%im;
• Implemented syntax str%len and a%kind;
• Implemented C descriptors and ISO_Fortran_binding.h header;
• Relaxed requirements for the result of the MAX and MIN functions when one of the arguments is NaN;
• Added option -fdec-include;
• Directive added BUILTIN.

libgccjit

• Feature added gcc_jit_context_add_driver_option.

Other

Many architecture- and OS-specific changes.

Source: linux.org.ru