[Bug target/78946] New: optimization throws internal compiler error for uint64_t on AVR

["thomas at maier-komor dot de" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78946

            Bug ID: 78946
           Summary: optimization throws internal compiler error for
                    uint64_t on AVR
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: thomas@maier-komor.de
  Target Milestone: ---

Created attachment 40427
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40427&action=edit
set of testcase files, compile testcase.cc with -O2 to reproduce ICE

The attached code produces for optimization levels -O2 an internal compiler
error while it works without an issue for -Os. this is at least with gcc-4.9.2
and 6.3.0

thomas@glaskugel:~/avr/arduino-mini/sensor1$ /opt/local/bin/avr-g++ --version
avr-g++ (GCC) 6.3.0
Copyright (C) 2016 Free Software Foundation, Inc.
Dies ist freie Software; die Kopierbedingungen stehen in den Quellen. Es
gibt KEINE Garantie; auch nicht für MARKTGÄNGIGKEIT oder FÜR SPEZIELLE ZWECKE.

thomas@glaskugel:~/avr/arduino-mini/sensor1$ /opt/local/bin/avr-g++ -c
-I/usr/lib/avr/include -O2 testcase.cc
testcase.cc: In Elementfunktion »size_t Sensor_AD::fromMemory(const void*,
size_t)«:
testcase.cc:127:1: Fehler: unerkennbarer Befehl:
 }
 ^
(insn 58 57 59 6 (parallel [
            (set (reg:HI 84)
                (minus:HI (subreg:HI (subreg:SI (reg:DI 81) 0) 0)
                    (reg:HI 82)))
            (clobber (scratch:QI))
        ]) testcase.cc:74 -1
     (nil))
testcase.cc:127:1: interner Compiler-Fehler: in extract_insn, bei recog.c:2287
0xa1abd8 _fatal_insn(char const*, rtx_def const*, char const*, int, char
const*)
        ../../gcc-6.3.0/gcc/rtl-error.c:108
0xa1ac09 _fatal_insn_not_found(rtx_def const*, char const*, int, char const*)
        ../../gcc-6.3.0/gcc/rtl-error.c:116
0x9f0c99 extract_insn(rtx_insn*)
        ../../gcc-6.3.0/gcc/recog.c:2287
0x84eb83 instantiate_virtual_regs_in_insn
        ../../gcc-6.3.0/gcc/function.c:1582
0x84eb83 instantiate_virtual_regs
        ../../gcc-6.3.0/gcc/function.c:1950
0x84eb83 execute
        ../../gcc-6.3.0/gcc/function.c:1999
Bitte senden Sie einen vollständigen Fehlerbericht auf Englisch ein;
inclusive vorverarbeitetem Quellcode, wenn es dienlich ist.
Please include the complete backtrace with any bug report.
Siehe <http://gcc.gnu.org/bugs.html> für nähere Anweisungen.


thomas@glaskugel:~/avr/arduino-mini/sensor1$ avr-g++ --version
avr-g++ (GCC) 4.9.2
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

thomas@glaskugel:~/avr/arduino-mini/sensor1$ avr-g++ -c -O2 testcase.cc
testcase.cc: In member function ‘size_t Sensor_AD::fromMemory(const void*,
size_t)’:
testcase.cc:127:1: error: unrecognizable insn:
 }
 ^
(insn 58 57 59 6 (parallel [
            (set (reg:HI 85)
                (minus:HI (subreg:HI (subreg:SI (reg:DI 82) 0) 0)
                    (reg:HI 83)))
            (clobber (scratch:QI))
        ]) testcase.cc:74 -1
     (nil))
testcase.cc:127:1: internal compiler error: in extract_insn, at recog.c:2202
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.