Created attachment 32973 [details]
Proposed patch

To reproduce the issue do:
1) Configure gcc for arm as traget and x86 as host.
$ ./configure --build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu --target=arm-v7a15v5r2-linux-gnueabi --prefix=/home/mzakirov/proj/gcc_arm_ref/arm-v7a15v5r2 --with-sysroot=/your_arm/sys-root
2) make -j6
3) make install
4) Compile following:
$ cat ex.c
int dummy(int a);

char a;

void mmm (void)
{
  char dyn[ dummy(3) ];
  a = (char)&dyn[0];
}
$ gcc -O3 ex.c -o ex.o 
ex.c: In function ‘mmm’:
ex.c:8:7: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
   a = (char)&dyn[0];
       ^
ex.c:9:1: internal compiler error: in check_rtl, at lra.c:1919
 }
 ^
0x8689e5 check_rtl
	/home/mzakirov/proj/gcc_arm_ref/build.arm.cortex-a15/sources/gcc_1/gcc/lra.c:1919
0x86bde5 lra(_IO_FILE*)
	/home/mzakirov/proj/gcc_arm_ref/build.arm.cortex-a15/sources/gcc_1/gcc/lra.c:2309
0x82b02e do_reload
	/home/mzakirov/proj/gcc_arm_ref/build.arm.cortex-a15/sources/gcc_1/gcc/ira.c:5325
0x82b02e execute
	/home/mzakirov/proj/gcc_arm_ref/build.arm.cortex-a15/sources/gcc_1/gcc/ira.c:5486
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.

Analysis showed that the problem in instruction like:
(insn 26 12 18 2 (set (reg:QI 2 r2)
        (reg:QI 13 sp)) ex.c:8 205 {*arm_movqi_insn}
     (nil))
gcc cse propogates sp register to (char/short) cast from a pointer (32 bit value) and reload phase fails because gcc do not founds applicable template for loading a byte or word from sp.
Adding correct template to arm.md fixes the issue. See attached patch.

Note: that issue appeared while translating linux kernel for arm.