[Bug rtl-optimization/51447] [4.6/4.7/4.8 Regression] global register variable definition incorrectly removed as dead code

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51447



--- Comment #14 from Steven Bosscher <steven at gcc dot gnu.org> 2012-11-12 
20:22:05 UTC ---

Author: steven

Date: Mon Nov 12 20:21:59 2012

New Revision: 193453



URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=193453

Log:

gcc/

    PR rtl-optimization/51447

    * df-scan.c (df_get_entry_block_def_set): Add global regs to the set.

    * df-problems.c (df_lr_local_compute): Make global regs always live.

    * dce.c (deletable_insn_p): Make insns setting a global reg

    inherently necessary.



testsuite/

    PR rtl-optimization/51447

    * gcc.c-torture/execute/pr51447.c: New test.





Added:

    trunk/gcc/testsuite/gcc.c-torture/execute/pr51447.c

Modified:

    trunk/gcc/ChangeLog

    trunk/gcc/dce.c

    trunk/gcc/df-problems.c

    trunk/gcc/df-scan.c

    trunk/gcc/testsuite/ChangeLog