Hi, The following was applied to the website to record additional GCC 6 changes for PowerPC. The changes passed XHTML verification.
Index: changes.html =================================================================== RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-6/changes.html,v retrieving revision 1.54 diff -r1.54 changes.html 361a362,434 > <li><p>PowerPC64 now supports IEEE 128-bit floating-point using the > __float128 data type. In GCC 6, this is NOT enabled by default, > but you can enable it with -mfloat128. The IEEE 128-bit > floating-point support requires the use of the VSX instruction > set. IEEE 128-bit floating-point values are passed and returned > as a single vector value. The software emulator for IEEE 128-bit > floating-point support is only built on PowerPC Linux systems > where the default cpu is at least power7. On future ISA 3.0 > systems (power9 and later), you will be able to use the > -mfloat128-hardware option to use the ISA 3.0 instructions > that support IEEE 128-bit floating-point. An additional type > (__ibm128) has been added to refer to the IBM extended double > type that normally implements long double. This will allow > for a future transition to implementing long double with IEEE > 128-bit floating-point.</p></li> > <li><p>Basic support has been added for POWER9 hardware that will use the > recently published OpenPOWER ISA 3.0 instructions. The following > new switches are available:</p> > <ul> > <li><p><u>-mcpu=power9</u>: Implement all of the ISA 3.0 > instructions supported by the compiler.</p></li> > <li><p><u>-mtune=power9</u>: In the future, apply tuning for > POWER9 systems. Currently, POWER8 tunings are used.</p></li> > <li><p><u>-mmodulo</u>: Generate code using the ISA 3.0 > integer instructions (modulus, count trailing zeros, array > index support, integer multiply/add).</p></li> > <li><p><u>-mpower9-fusion</u>: Generate code to suitably fuse > instruction sequences for a POWER9 system.</p></li> > <li><p><u>-mpower9-dform</u>: Generate code to use the new D-form > (register +offset) memory instructions for the vector > registers.</p></li> > <li><p><u>-mpower9-vector</u>: Generate code using the new ISA > 3.0 vector (VSX or Altivec) instructions.</p></li> > <li><p><u>-mpower9-minmax</u>: Reserved for future development. > </p></li> > <li><p><u>-mtoc-fusion</u>: Keep TOC entries together to provide > more fusion opportunities.</p></li> > </ul></li> > <li><p>New constraints have been added to support IEEE 128-bit > floating-point and ISA 3.0 instructions:</p> > <ul> > <li><p><u>wb</u>: Altivec register if -mpower9-dform is > enabled.</p></li> > <li><p><u>we</u>: VSX register if -mpower9-vector is enabled > for 64-bit code generation.</p></li> > <li><p><u>wo</u>: VSX register if -mpower9-vector is > enabled.</p></li> > <li><p><u>wp</u>: Reserved for future use if long double > is implemented with IEEE 128-bit floating-point instead > of IBM extended double.</p></li> > <li><p><u>wq</u>: VSX register if -mfloat128 is enabled.</p></li> > <li><p><u>wF</u>: Memory operand suitable for POWER9 fusion > load/store.</p></li> > <li><p><u>wG</u>: Memory operand suitable for TOC fusion memory > references.</p></li> > <li><p><u>wL</u>: Integer constant identifying the element > number mfvsrld accesses within a vector.</p></li> > </ul></li> > <li><p>Support has been added for __builtin_cpu_is () and > __builtin_cpu_supports (), allowing for very fast access to > AT_PLATFORM, AT_HWCAP, and AT_HWCAP2 values. This requires > use of glibc 2.23 or later.</p></li> > <li><p>All hardware transactional memory builtins now correctly > behave as memory barriers. Programmers can use #ifdef __TM_FENCE__ > to determine whether their "old" compiler treats the builtins > as barriers.</p></li> > <li><p>Split-stack support has been added for gccgo on PowerPC64 > for both big- and little-endian (but NOT for 32-bit). The gold > linker from at least binutils 2.25.1 must be available in the PATH > when configuring and building gccgo to enable split stack. (The > requirement for binutils 2.25.1 applies to PowerPC64 only.) The > split-stack feature allows a small initial stack size to be > allocated for each goroutine, which increases as needed.</p></li>
