This is the mail archive of the mailing list for the GCC project.

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[4.9 RFA PATCH, RTL-optimization]: Backport recent AND-alignment alias fixes to 4.9 branch


I would like to backport recent alias fixes to correctly handle memory
references with AND-alignment to 4.9 branch. These patches fix
hundreds of failures in gfortran testsuite on alpha-linux-gnu due to
invalid aliasing of AND-aligned memory references of two QImode flags.

These patches were baking for a couple of weeks in the mainline
without problems. Modulo removal of old and unnecessary functionality,
these changes affect only alpha target.

2014-10-30  Uros Bizjak  <>

    Backport from mainline:
    2014-10-20  Uros Bizjak  <>

    * varasm.c (const_alias_set): Remove.
    (init_varasm_once): Remove initialization of const_alias_set.
    (build_constant_desc): Do not set alias set to const_alias_set.

    Backport from mainline:
    2014-10-14  Uros Bizjak  <>

    PR rtl-optimization/63475
    * alias.c (true_dependence_1): Always use get_addr to extract
    true address operands from x_addr and mem_addr.  Use extracted
    address operands to check for references with alignment ANDs.
    Use extracted address operands with find_base_term and
    base_alias_check. For noncanonicalized operands call canon_rtx with
    extracted address operand.
    (write_dependence_1): Ditto.
    (may_alias_p): Ditto.  Remove unused calls to canon_rtx.

    Backport from mainline:
    2014-10-10  Uros Bizjak  <>

    PR rtl-optimization/63483
    * alias.c (true_dependence_1): Do not exit early for MEM_READONLY_P
    references when alignment ANDs are involved.
    (write_dependence_p): Ditto.
    (may_alias_p): Ditto.

The complete backport was tested on alpha-linux-gnu,
alphaev68-linux-gnu and x86_64-linux-gnu on 4.9 branch.

OK for branch?


Attachment: alias-49.diff.txt
Description: Text document

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]