[Bug target/58784] New: [ARM] LRA legitimate address issue with misalign neon_store

["yvan.roux at linaro dot org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58784

            Bug ID: 58784
           Summary: [ARM] LRA legitimate address issue with misalign
                    neon_store
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: yvan.roux at linaro dot org

Created attachment 31035
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31035&action=edit
testcase

The attached testcase failed on ARM with LRA enabled during the legitimate
address checking of the movmisaligndi_neon_store insn. Notice that this issue
is the root cause of all the LRA testsuite regressions (in gcc/g++, libstdc++
and fortran).

command line to reproduce:

cc1 -quiet unalign-1.c -march=armv7-a -mfloat-abi=hard -mfpu=neon -marm -O2
-mlra

error on insn:

(insn 12 7 14 2 (set (mem:DI (plus:SI (plus:SI (mult:SI (reg:SI 0 r0 [
sequenceId ])
                        (const_int 8 [0x8]))
                    (reg/f:SI 102 sfp))
                (const_int -3 [0xfffffffffffffffd])) [2 *_4+0 S8 A8])
        (unspec:DI [
                (reg:DI 117 [ D.4956 ])
            ] UNSPEC_MISALIGNED_ACCESS)) unalign-1.c:13 819
{*movmisaligndi_neon_store}
     (expr_list:REG_DEAD (reg:DI 117 [ D.4956 ])
        (expr_list:REG_DEAD (reg:SI 0 r0 [ sequenceId ])
            (nil))))