[Bug c/53726] New: [4.8 Regression] aes test performance drop for eembc_2_0_peak_32

["vbyakovl23 at gmail dot com" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53726

             Bug #: 53726
           Summary: [4.8 Regression] aes test performance drop for
                    eembc_2_0_peak_32
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: vbyakovl23@gmail.com


After fix

r188261 | rguenth | 2012-06-06 13:45:27 +0400 (Wed, 06 Jun 2012) | 23 lines

2012-06-06  Richard Guenther  <rguenther@suse.de>

        PR tree-optimization/53081
        * tree-data-ref.h (adjacent_store_dr_p): Rename to ...
        (adjacent_dr_p): ... this and make it work for reads, too.
        * tree-loop-distribution.c (enum partition_kind): Add PKIND_MEMCPY.
        (struct partition_s): Change main_stmt to main_dr, add
        secondary_dr member.
        (build_size_arg_loc): Change to date data-reference and not
        gimplify here.
        (build_addr_arg_loc): New function split out from ...
        (generate_memset_builtin): ... here.  Use it and simplify.
        (generate_memcpy_builtin): New function.
        (generate_code_for_partition): Adjust.
        (classify_partition): Streamline pattern detection.  Detect
        memcpy.
        (ldist_gen): Adjust.
        (tree_loop_distribution): Adjust seed statements for memcpy
        recognition.

        * gcc.dg/tree-ssa/ldist-20.c: New testcase.
        * gcc.dg/tree-ssa/loop-19.c: Add -fno-tree-loop-distribute-patterns.

regression on Atom 11%, on Sundy Bridge 30%. The fix lead to unrecognition of
memcpy. Reduced test case and assemblers are attached. Command line to
reproduce

gcc -ansi -O3 -ffast-math -msse2 -mfpmath=sse -m32 -static  -march=corei7
-mtune=corei7   test.c