[Bug middle-end/95052] [9/10/11 Regression] Excess padding of partially initialized strings/char arrays

["mkuvyrkov at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95052

--- Comment #10 from Maxim Kuvyrkov <mkuvyrkov at gcc dot gnu.org> ---
To reproduce:

1. Configure GCC for arm-linux-gnueabihf (e.g., for x86_64->armhf cross):
--with-gnu-as --with-gnu-ld --disable-libmudflap --enable-lto --enable-shared
--without-included-gettext --enable-nls --with-system-zlib
--disable-sjlj-exceptions --enable-gnu-unique-object --enable-linker-build-id
--disable-libstdcxx-pch --enable-c99 --enable-clocale=gnu
--enable-libstdcxx-debug --enable-long-long --with-cloog=no --with-ppl=no
--with-isl=no --disable-multilib --with-float=hard --with-fpu=vfpv3-d16
--with-mode=thumb --with-tune=cortex-a9 --with-arch=armv7-a
--enable-threads=posix --enable-multiarch --enable-libstdcxx-time=yes
--enable-gnu-indirect-function --disable-libssp --disable-libquadmath
--disable-threads --without-headers --with-newlib --disable-libmudflap
--disable-bootstrap --disable-decimal-float --disable-libgomp
--disable-libatomic --disable-libsanitizer --disable-plugins --disable-libitm
--disable-shared --with-glibc-version=2.18 --disable-libstdcxx --disable-libvtv
--enable-languages=c,c++ --build=x86_64-unknown-linux-gnu
--host=x86_64-unknown-linux-gnu --target=arm-linux-gnueabihf

2. Try compiling attached pre-processed file:
.../cc1 -fpreprocessed libata-eh.i -quiet -dumpdir drivers/ata/ -dumpbase
libata-eh.c -dumpbase-ext .c -mlittle-endian -mabi=aapcs-linux -mfpu=vfp -marm
-mfloat-abi=soft -mtune=cortex-a9 -mtls-dialect=gnu -march=armv7-a -O2 -Wall
-Wundef -Werror=strict-prototypes -Wno-trigraphs
-Werror=implicit-function-declaration -Werror=implicit-int -Wno-format-security
-Wno-frame-address -Wformat-truncation=0 -Wformat-overflow=0
-Wno-address-of-packed-member -Wframe-larger-than=1024
-Wno-unused-but-set-variable -Wimplicit-fallthrough=3 -Wunused-const-variable=0
-Wdeclaration-after-statement -Wvla -Wno-pointer-sign -Wno-stringop-truncation
-Wno-zero-length-bounds -Wno-array-bounds -Wstringop-overflow=0 -Wno-restrict
-Wno-maybe-uninitialized -Werror=date-time -Werror=incompatible-pointer-types
-Werror=designated-init -Wno-packed-not-aligned -std=gnu90 -version
-fno-strict-aliasing -fno-common -fshort-wchar -fno-PIE -fno-dwarf2-cfi-asm
-fno-ipa-sra -funwind-tables -fno-delete-null-pointer-checks
-fno-allow-store-data-races -fstack-protector-strong -fomit-frame-pointer
-fno-var-tracking-assignments -fno-strict-overflow -fno-merge-all-constants
-fmerge-constants -fstack-check=no -fconserve-stack -fmacro-prefix-map=./=  -o
libata-eh.s

3. It should crash with:
...
during RTL pass: expand
drivers/ata/libata-eh.c: In function \u2018ata_eh_link_report\u2019:
drivers/ata/libata-eh.c:2293:8: internal compiler error: in store_expr, at
expr.c:5845
0x8e8a56 store_expr(tree_node*, rtx_def*, int, bool, bool)