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These four UNSPECS seems could be replaced with native RTL. For "(set (reg:SI VSCR_REGNO) (unspec:SI [(const_int 0)] UNSPEC_SET_VSCR))": Quoted David's explanation: "The design came from the early implementation of Altivec: https://gcc.gnu.org/pipermail/gcc-patches/2002-May/077409.html If one later checks for saturation (reads VSCR), one needs a corresponding SET of the value. It's set in an architecture-specific manner that isn't described to GCC, but it's set, not just clobbered and in an undefined state. The RTL does not describe that VSCR is set to the value 0. The (const_int 0) is not the value set. You can think of the (const_int 0) as a dummy RTL argument to the VSCR UNSPEC. UNSPEC requires at least one argument and the pattern doesn't try to express the argument, so it uses a dummy RTL constant. It's part of a PARALLEL and the plus or minus already expresses the data dependency of the pattern on the input operands." gcc/ChangeLog: 2021-12-21 Xionghu Luo <luoxhu@linux.ibm.com> * config/rs6000/altivec.md (altivec_vaddu<VI_char>s): Replace UNSPEC_VADDU with us_plus. (altivec_vadds<VI_char>s): Replace UNSPEC_VADDS with ss_plus. (altivec_vsubu<VI_char>s): Replace UNSPEC_VSUBU with us_minus. (altivec_vsubs<VI_char>s): Replace UNSPEC_VSUBS with ss_minus. (altivec_abss_<mode>): Likewise. |
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| c++tools | ||
| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| intl | ||
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| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgo | ||
| libgomp | ||
| libiberty | ||
| libitm | ||
| libobjc | ||
| liboffloadmic | ||
| libphobos | ||
| libquadmath | ||
| libsanitizer | ||
| libssp | ||
| libstdc++-v3 | ||
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| lto-plugin | ||
| maintainer-scripts | ||
| zlib | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| ABOUT-NLS | ||
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| libtool-ldflags | ||
| libtool.m4 | ||
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