On January 27, 2017 5:30:51 PM GMT+01:00, Jakub Jelinek <ja...@redhat.com> wrote: >Hi! > >This patch attempts to document some new features (without warnings, >those are partially covered by Marek's patch, C++ FE (would be nice >to document -faligned-new, -fnew-inheriting-ctors, -fnew-ttp-matching, >-fstrong-eval-order and what from C++ is supported) and the BRIG FE). > >Ok for wwwdocs?
LGTM. Richard. >Index: changes.html >=================================================================== >RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-7/changes.html,v >retrieving revision 1.44 >diff -u -p -r1.44 changes.html >--- changes.html 27 Jan 2017 09:54:32 -0000 1.44 >+++ changes.html 27 Jan 2017 16:23:03 -0000 >@@ -45,8 +45,39 @@ a work-in-progress.</h2> ><li>A new store merging pass has been added. It merges constant stores >to > adjacent memory locations into fewer, wider, stores. >It can be enabled by using the <code>-fstore-merging</code> option and >is >- enabled by default at <code>-Os</code> and the <code>-O2</code> >optimization >- level or higher.</li> >+ enabled by default at the <code>-O2</code> optimization >+ level or higher (including <code>-Os</code>).</li> >+ >+ <li>A new code hoisting optimization has been added to the partial >+ redundancy elimination pass. It attempts to move evaluation of >+ expressions executed on all paths to the function exit as early as >+ possible, which helps primarily for code size, but can be useful for >+ speed of generated code as well. It can be enabled by using the >+ <code>-fcode-hoisting</code> option and is enabled by default at >+ the <code>-O2</code> optimization level or higher.</li> >+ >+ <li>A new interprocedural bitwise constant propagation optimization >+ has been added, which propagates knowledge about which bits of >variables >+ are known to be zero (including pointer alignment information) >across >+ the call graph. It can be enabled by using the ><code>-fipa-bit-cp</code> >+ option if <code>-fipa-cp</code> is enabled as well, and is enabled >by >+ default at the <code>-O2</code> optimization level and higher.</li> >+ >+ <li>A new interprocedural value range propagation optimization has >been >+ added, which propagates integral ranges that variable values can be >proven >+ to be within across the call graph. It can be enabled by using the >+ <code>-fipa-vrp</code> option and is enabled by default at the >+ <code>-O2</code> optimization level and higher.</li> >+ >+ <li>A new loop splitting optimization pass has been added. It >splits >+ certain loops if they contain a condition that is always true on one >+ side of the iteration space and always false on the other into two >+ loops where each of the new two loops iterates just on one of the >sides >+ of the iteration space and the condition does not need to be checked >+ inside of the loop. It can be enabled by using the >+ <code>-fsplit-loops</code> option and is enabled by default at the >+ <code>-O3</code> optimization level or higher.</li> >+ ><li>AddressSanitizer gained a new sanitization option, ><code>-fsanitize-address-use-after-scope</code>, >which enables sanitization of variables whose address is taken and used >after a scope where the > variable is defined: >@@ -64,17 +95,17 @@ main (int argc, char **argv) > return *ptr; > } > >-==28882==ERROR: AddressSanitizer: stack-use-after-scope on address >0x7fffb8dba990 at pc 0x0000004006d5 bp 0x7fffb8dba960 sp 0x7fffb8dba958 >-WRITE of size 1 at 0x7fffb8dba990 thread T0 >+<span class="boldred">==28882==ERROR: AddressSanitizer: >stack-use-after-scope on address 0x7fffb8dba990 at pc 0x0000004006d5 bp >0x7fffb8dba960 sp 0x7fffb8dba958</span> >+<span class="boldblue">WRITE of size 1 at 0x7fffb8dba990 thread >T0</span> > #0 0x4006d4 in main /tmp/use-after-scope-1.c:10 > #1 0x7f9c71943290 in __libc_start_main (/lib64/libc.so.6+0x20290) > #2 0x400739 in _start (/tmp/a.out+0x400739) > >-Address 0x7fffb8dba990 is located in stack of thread T0 at offset 32 >in frame >+<span class="boldlime">Address 0x7fffb8dba990 is located in stack of >thread T0 at offset 32 in frame</span> > #0 0x40067f in main /tmp/use-after-scope-1.c:3 > > This frame has 1 object(s): >- [32, 33) 'my_char' <== Memory access at offset 32 is inside >this variable >+ [32, 33) 'my_char' <span class="boldlime"><== Memory access at >offset 32 is inside this variable</span> > </pre></blockquote> > >The option is enabled by default with <code>-fsanitize=address</code> >and disabled >@@ -92,6 +123,16 @@ Address 0x7fffb8dba990 is located in sta > > </li> > >+ <li>The <code>-fsanitize=signed-integer-overflow</code> suboption of >the >+ UndefinedBehavior Sanitizer now diagnose arithmetic overflows even >on >+ arithmetic operations with generic vectors.</li> >+ >+ <li>The upcoming version 5 of the <a >+ href="http://www.dwarfstd.org/Download.php";>DWARF</a> debugging >+ information standard is supported through the <code>-gdwarf-5</code> >+ option. The DWARF version 4 debugging information remains the >+ default until debugging information consumers are adjusted.</li> >+ > </ul> > ><!-- .................................................................. >--> >@@ -255,6 +296,14 @@ of the global declaration:</p> > currently has the value of <code>UINTMAX_MAX</code> on all systems, > reflecting that GCC's compile-time conversions are correctly rounded > for any number of digits.</li> >+<li>New <code>__builtin_add_overflow_p</code>, >+ <code>__builtin_sub_overflow_p</code>, >+ <code>__builtin_mul_overflow_p</code> built-in functions have been >added. >+ These work similarly to earlier added built-in functions without the >+ <code>_p</code> suffix, but don't actually store the result of the >+ arithmetics anywhere, just return whether the operation would >overflow. >+ These builtins allow easy checking for overflows e.g. in C++ >+ <code>constexpr</code> contexts.</li> > </ul> > > <h3 id="c">C</h3> >@@ -291,6 +340,8 @@ of the global declaration:</p> > (suffixed <code>f<i>N</i></code> or <code>f<i>N</i>x</code>) for the > new >types: <code>__builtin_copysign</code>, <code>__builtin_fabs</code>, ><code>__builtin_huge_val</code>, <code>__builtin_inf</code>, ><code>__builtin_nan</code>, <code>__builtin_nans</code>.</p></li> >+ <li>Compilation with <code>-fopenmp</code> is now compatible with >+ C11 <code>_Atomic</code> keyword.</li> > </ul> > > <h3 id="cxx">C++</h3> >@@ -428,11 +479,17 @@ Fortran runtime error: Loop iterates inf > </pre></blockquote> > </li> > >+ <li>Version 4.5 of the <a >href="http://www.openmp.org/specifications/"; >+ >OpenMP specification</a> is now partially supported also in the >+ Fortran compilers, largest missing support in the Fortran >frontend >+ is structure element mapping .</li> > </ul> > > <!-- <h3 id="go">Go</h3> --> > >-<!-- <h3 id="java">Java (GCJ)</h3> --> >+<h3 id="java">Java (GCJ)</h3> >+<p>The GCC Java frontend and associated libjava runtime library have >been >+removed from GCC.</p> > ><!-- .................................................................. >--> > <h2 id="jit">libgccjit</h2> >@@ -561,7 +618,13 @@ const int* get_address (unsigned idx) > > <!-- <h3 id="hsa">Heterogeneous Systems Architecture</h3> --> > >-<!-- <h3 id="x86">IA-32/x86-64</h3> --> >+<h3 id="x86">IA-32/x86-64</h3> >+<ul> >+ <li>Support for the AVX-512 Fused Multiply Accumulation Packed >Single precision >+ (4FMAPS), AVX-512 Vector Neural Network Instructions Word variable >precision >+ (4VNNIW), AVX-512 Vector Population Count (VPOPCNTDQ) and Software >+ Guard Extensions (SGX) ISA extensions has been added.</li> >+</ul> > > <!-- <h3 id="mips">MIPS</h3> --> > >@@ -571,12 +634,23 @@ const int* get_address (unsigned idx) > > <!-- <h3 id="nds32">NDS32</h3> --> > >+<h3 id="nvptx">NVPTX</h3> >+<ul> >+ <li>OpenMP target regions can now be offloaded to NVidia PTX GPGPUs. >+ See https://gcc.gnu.org/wiki/Offloading on how to configure >it.</li> >+</ul> >+ > <h3 id="powerpc">PowerPC / PowerPC64 / RS6000</h3> > <ul> > <li>The PowerPC port now uses LRA by default.</li> > <li>GCC now diagnoses inline assembly that clobbers register r2. > This has always been invalid code, and is no longer quietly > tolerated.</li> >+ <li>Shrink-wrapping optimization can now separate portions of >+ prologues and epilogues to improve performance if some of the >+ work done traditionally by prologues and epilogues is not needed >+ on certain paths. This is controlled by the >+ <code>-fshrink-wrap-separate</code> option, enabled by >default.</li> > </ul> > > <!-- <h3 id="s390">S/390, System z, IBM z Systems</h3> --> > > Jakub
