4.7: ICE in reload_cse_simplify_operands, at postreload.c:403 with -O1 -march=armv7-a -mthumb

Attaching reduced test case:

[bero@localhost grouper-4.1.1]$ /opt/android-toolchain-4.7/bin/arm-linux-androideabi-g++ -O1 -mthumb -march=armv7-a -c bug1046999.cc -o bug1046999.o
bug1046999.cc: In function 'void bug1046999()':
bug1046999.cc:12:1: error: insn does not satisfy its constraints:
(insn 121 120 52 2 (set (zero_extract:SI (reg/f:SI 13 sp)
            (const_int 16 [0x10])
            (const_int 16 [0x10]))
        (const_int 65535 [0xffff])) bug1046999.cc:3 348 {*arm_movtas_ze}
     (nil))
bug1046999.cc:12:1: internal compiler error: in reload_cse_simplify_operands, at postreload.c:403
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Thank you for the bug report. I've confirmed this with gcc-linaro-4.7+bzr115016.

michaelh@crucis:~/linaro/bugs$ ~/linaro/gcc/build/4.7/install/bin/arm-linux-gnueabi-g++ -O1 -S bug1046999.cc
bug1046999.cc: In function ‘void bug1046999()’:
bug1046999.cc:12:1: error: insn does not satisfy its constraints:
(insn 117 116 48 2 (set (zero_extract:SI (reg/f:SI 13 sp)
            (const_int 16 [0x10])
            (const_int 16 [0x10]))
        (const_int 65535 [0xffff])) bug1046999.cc:3 348 {*arm_movtas_ze}
     (nil))
bug1046999.cc:12:1: internal compiler error: in reload_cse_simplify_operands, at postreload.c:403

The fault is introduced by bzr115014 and is caused by the new add pattern not handling a sp = rx + constant pattern, causing reload to turn this into a movw, movt, and add. The pattern above is the movt part.

The fault exists upstream as at svn191044. Could you report it in GCC bugzilla and record it against this ticket?

I've set this to high priority as it's an ICE with no work around.

Oh, and the fault was introduced in svn190472 by rearnshaw.

It seems that the r/r/k patterns used for other forms also need doing for the add. A shortcut is to remove the k constraint from the first operand, forcing sp adds to use a later alternative.

Upstream bug report http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54516

Marked as affecting. Will bring up at todays meeting. Revert underway.

Reverted.