compiling R packages `data.table` and `xfun` among others fails during `install.packages()` call

I've recently installed R version 4.0.5 (2021-03-31) onto Ubuntu 20.04.2 LTS. R is working as expected. Some packages have installed without issue (e.g., R.matlab); however, there are several packages that have not been able to install.

As as example, running install.packages("data.table") throws the following error:
* installing *source* package ‘data.table’ ...
** package ‘data.table’ successfully unpacked and MD5 sums checked
** using staged installation
gcc -std=gnu99 9.3.0
zlib 1.2.11 is available ok
R CMD SHLIB supports OpenMP without any extra hint
** libs
gcc -std=gnu99 -I"/usr/share/R/include" -DNDEBUG -fopenmp -fpic -g -O2 -fdebug-prefix-map=/build/r-base-tRgc13/r-base-4.0.5=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g -c assign.c -o assign.o
during GIMPLE pass: ccp
assign.c: In function ‘memrecycle’:
assign.c:1205:1: internal compiler error: Segmentation fault
 1205 | }
      | ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-9/README.Bugs> for instructions.
make: *** [/usr/lib/R/etc/Makeconf:172: assign.o] Error 1
ERROR: compilation failed for package ‘data.table’

Similarly, if `install.packages("xfun") is executed in R, the following error is thrown:
* installing *source* package ‘xfun’ ...
** package ‘xfun’ successfully unpacked and MD5 sums checked
** using staged installation
** libs
gcc -std=gnu99 -I"/usr/share/R/include" -DNDEBUG -fpic -g -O2 -fdebug-prefix-map=/build/r-base-tRgc13/r-base-4.0.5=. -fstack-protector-strong -Wformat -Werror=format-security -Wdate-time -D_FORTIFY_SOURCE=2 -g -c base64.c -o base64.o
during GIMPLE pass: ccp
base64.c: In function ‘base64_decode_impl’:
base64.c:237:1: internal compiler error: Segmentation fault
  237 | }
      | ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <file:///usr/share/doc/gcc-9/README.Bugs> for instructions.
make: *** [/usr/lib/R/etc/Makeconf:172: base64.o] Error 1

Other packages have installed without issue. I have posted the question to stackoverflow and it was suggested that I submit a bug report. As I am relatively new to this, I've decided to ask a question instead.

Thanks for all your help and work in advance.

gcc -v:
sing built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/9/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:hsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 9.3.0-17ubuntu1~20.04' --with-bugurl=file:///usr/share/doc/gcc-9/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++,gm2 --prefix=/usr --with-gcc-major-version-only --program-suffix=-9 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib=auto --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none=/build/gcc-9-HskZEa/gcc-9-9.3.0/debian/tmp-nvptx/usr,hsa --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04)