[Bug target/91903] New: vec_ctf altivec intrinsic can cause ICE on powerpc

[murphyp at linux dot vnet.ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91903

            Bug ID: 91903
           Summary: vec_ctf altivec intrinsic can cause ICE on powerpc
           Product: gcc
           Version: 7.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: murphyp at linux dot vnet.ibm.com
  Target Milestone: ---

I was running some tests against the powerpc altivec intrinsics and the
following dubious usage of vec_ctf causes an ICE using "gcc -c test.c":

----

#include <altivec.h>
vector double test(vector unsigned long a, const int b)
{
vector double ret;
ret = vec_ctf(a,b);
return ret;
}

----

during RTL pass: expand
test.c: In function ‘test’:
test.c:5:5: internal compiler error: in copy_to_mode_reg, at explow.c:630
 ret = vec_ctf(a,b);
 ~~~~^~~~~~~~~~~~~~
Please submit a full bug report,
with preprocessed source if appropriate.
See <https://gcc.gnu.org/bugs/> for instructions.

----
gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/powerpc64le-linux-gnu/7/lto-wrapper
Target: powerpc64le-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
7.4.0-1ubuntu1~18.04.1' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++ --prefix=/usr
--with-gcc-major-version-only --program-suffix=-7
--program-prefix=powerpc64le-linux-gnu- --enable-shared
--enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/
--enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-libquadmath --disable-libquadmath-support --enable-plugin
--enable-default-pie --with-system-zlib --enable-objc-gc=auto
--enable-secureplt --with-cpu=power8 --enable-targets=powerpcle-linux
--disable-multilib --enable-multiarch --disable-werror --with-long-double-128
--enable-checking=release --build=powerpc64le-linux-gnu
--host=powerpc64le-linux-gnu --target=powerpc64le-linux-gnu
Thread model: posix
gcc version 7.4.0 (Ubuntu 7.4.0-1ubuntu1~18.04.1)
----