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[Bug rtl-optimization/40086] [4.5 Regression]: cris-elf gfortran.dg/forall_1.f90 -O1 execution
- From: "hp at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 13 May 2009 13:09:59 -0000
- Subject: [Bug rtl-optimization/40086] [4.5 Regression]: cris-elf gfortran.dg/forall_1.f90 -O1 execution
- References: <bug-40086-507@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #12 from hp at gcc dot gnu dot org 2009-05-13 13:09 -------
The relax_delay_slots (first) call finds that there's a branch to a redundant
insn that it can eliminate. It does this by redirecting the branch to a new or
existing label and deleting the insn, or rather move it and make it a USE-mark
at the "new" label. When doing this, the old USE-mark quoted above (not
related to the new USE-mark by other means being before it in the execution
path) is now deemed unreachable and removed by jump.c:delete_related_insns.
So, it seems a solution will include propagating existing USE-marks when
redirecting branch labels, perhaps in reorg_redirect_jump or update_block.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40086