On 13-03-04 4:17 PM, Jakub Jelinek wrote:
Hi!

Something that again hits lots of testcases during valgrind checking
bootstrap.  init_alias_analysis apparently does
   vec_safe_grow_cleared (reg_known_value, maxreg - FIRST_PSEUDO_REGISTER);
   reg_known_equiv_p = sbitmap_alloc (maxreg - FIRST_PSEUDO_REGISTER);
but doesn't bitmap_clear (reg_known_equiv_p), perhaps as an optimization?
Sorry, I don't know current state of alias.c well to say something definite about this. But I believe it should be cleared.
If set_reg_known_value is called (and not to the reg itself),
set_reg_known_equiv_p is called too though.
Right now get_reg_known_equiv_p is only called in one place, and we are only
interested in MEM_P known values there, so the following works fine.
Though perhaps if in the future we use the reg_known_equiv_p bitmap more,
we should bitmap_clear (reg_known_equiv_p) it instead.
Bootstrapped/regtested on x86_64-linux and i686-linux.

Ok for trunk (or do you prefer to slow down init_alias_analysis and just
clear the bitmap)?
I don't see any harm from your patch but I guess it should be fixed by clearing reg_know_equiv_p. I think you need Steven's opinion on this as he is an author of the code.

2013-03-04  Jakub Jelinek  <ja...@redhat.com>

        * sched-deps.c (sched_analyze_reg): Only call get_reg_known_equiv_p
        if get_reg_known_value returned non-NULL.

--- gcc/sched-deps.c.jj 2013-03-04 12:21:09.000000000 +0100
+++ gcc/sched-deps.c    2013-03-04 17:29:03.478944157 +0100
@@ -2351,10 +2351,10 @@ sched_analyze_reg (struct deps_desc *dep
        /* Pseudos that are REG_EQUIV to something may be replaced
         by that during reloading.  We need only add dependencies for
        the address in the REG_EQUIV note.  */
-      if (!reload_completed && get_reg_known_equiv_p (regno))
+      if (!reload_completed)
        {
          rtx t = get_reg_known_value (regno);
-         if (MEM_P (t))
+         if (t && MEM_P (t) && get_reg_known_equiv_p (regno))
            sched_analyze_2 (deps, XEXP (t, 0), insn);
        }


Reply via email to