[Bug target/60949] New: Thumb2 LRA ICE for case pr34856.c

[tony.wang at arm dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60949

            Bug ID: 60949
           Summary: Thumb2 LRA ICE for case pr34856.c
           Product: gcc
           Version: 4.10.0
            Status: UNCONFIRMED
          Severity: blocker
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: tony.wang at arm dot com

I'm running regression test for the latest GCC trunk, and run into below ICE.
And if I disable the LRA feature with option mno-lra, the test case will pass:

./install-native/bin/arm-none-eabi-gcc -fno-diagnostics-show-caret -O3
-fomit-frame-pointer -funroll-loops  -w -c    -mthumb -mcpu=cortex-m3 -o
pr34856.o 
./src/gcc/gcc/testsuite/gcc.c-torture/compile/pr34856.c
./src/gcc/gcc/testsuite/gcc.c-torture/compile/pr34856.c: In function 'f1':
./src/gcc/gcc/testsuite/gcc.c-torture/compile/pr34856.c:17:1: internal compiler
error: in split_reg, at lra-constraints.c:4801
0x854bfc split_reg
   
/work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/lra-constraints.c:4801
0x8558a5 split_if_necessary
   
/work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/lra-constraints.c:4904
0x85df76 inherit_in_ebb
   
/work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/lra-constraints.c:5391
0x85df76 lra_inheritance()
   
/work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/lra-constraints.c:5552
0x84d74a lra(_IO_FILE*)
    /work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/lra.c:2368
0x80fb36 do_reload
    /work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/ira.c:5457
0x80fb36 execute
    /work/arm_gcc/gcc-arm-none-eabi-4_8-2014q1-20140314/src/gcc/gcc/ira.c:5618
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.