1bd3a8af85
The attached patch eliminates a redundant zero extend from the AArch64 backend. Given the following C code:
unsigned long long foo(unsigned a)
{
return ~a;
}
prior to this patch, AArch64 GCC at -O2 generates:
foo:
mvn w0, w0
uxtw x0, w0
ret
but the uxtw is redundant, since the mvn clears the upper half of the x0 register. After applying this patch, GCC at -O2 gives:
foo:
mvn w0, w0
ret
Testing:
Added regression test which passes after applying the change to aarch64.md.
Full bootstrap and regression on aarch64-linux with no additional failures.
* config/aarch64/aarch64.md (*one_cmpl_zero_extend): New.
* gcc.target/aarch64/mvn_zero_ext.c: New test.
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| config | ||
| contrib | ||
| fixincludes | ||
| gcc | ||
| gnattools | ||
| gotools | ||
| include | ||
| INSTALL | ||
| intl | ||
| libada | ||
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| libcpp | ||
| libdecnumber | ||
| libffi | ||
| libgcc | ||
| libgfortran | ||
| libgo | ||
| libgomp | ||
| libhsail-rt | ||
| libiberty | ||
| libitm | ||
| libobjc | ||
| liboffloadmic | ||
| libphobos | ||
| libquadmath | ||
| libsanitizer | ||
| libssp | ||
| libstdc++-v3 | ||
| libvtv | ||
| lto-plugin | ||
| maintainer-scripts | ||
| zlib | ||
| .dir-locals.el | ||
| .gitattributes | ||
| .gitignore | ||
| ABOUT-NLS | ||
| ar-lib | ||
| ChangeLog | ||
| ChangeLog.jit | ||
| ChangeLog.tree-ssa | ||
| compile | ||
| config-ml.in | ||
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| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| COPYING.LIB | ||
| COPYING.RUNTIME | ||
| depcomp | ||
| install-sh | ||
| libtool-ldflags | ||
| libtool.m4 | ||
| lt~obsolete.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
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| missing | ||
| mkdep | ||
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| README | ||
| symlink-tree | ||
| test-driver | ||
| ylwrap | ||
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