Re: [PARCH 2/2, x86, PR63534] Fix darwin bootstrap

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Oct 22, 2014 at 03:34:38PM -0600, Jeff Law wrote:
> >--- a/gcc/cse.c
> >+++ b/gcc/cse.c
> >@@ -6953,6 +6953,11 @@ delete_trivially_dead_insns (rtx_insn *insns, int nreg)
> >        /* If no debug insns can be present, COUNTS is just an array
> >          which counts how many times each pseudo is used.  */
> >      }
> >+  /* Pseudo PIC register should be considered as used due to possible
> >+     new usages generated.  */
> >+  if (pic_offset_table_rtx
> >+      && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
> >+    counts[REGNO (pic_offset_table_rtx)]++;
> >    /* Go from the last insn to the first and delete insns that only set unused
> >       registers or copy a register to itself.  As we delete an insn, remove
> >       usage counts for registers it uses.
> Shouldn't this also be guarded with !reload_completed?  One reload is
> complete all the implicit references to the PIC register should be explicit
> and thus there's no need to treat the PIC register special.

Supposedly this one yes.

> >diff --git a/gcc/dce.c b/gcc/dce.c
> >index 5b7d36e..a52a59c 100644
> >--- a/gcc/dce.c
> >+++ b/gcc/dce.c
> >@@ -127,6 +127,10 @@ deletable_insn_p (rtx_insn *insn, bool fast,
> >bitmap arg_stores)
> >      if (HARD_REGISTER_NUM_P (DF_REF_REGNO (def))
> >         && global_regs[DF_REF_REGNO (def)])
> >        return false;
> >+    /* Initialization of pseudo PIC register should never be removed.  */
> >+    else if (DF_REF_REG (def) == pic_offset_table_rtx
> >+            && REGNO (pic_offset_table_rtx) >= FIRST_PSEUDO_REGISTER)
> >+      return false;
> Similarly.

But here, after reload completes, there shouldn't be pseudos in the IL, so
the condition should not trigger anymore.

	Jakub