On Mon, Dec 3, 2012 at 9:19 PM, Steven Bosscher wrote: >> So the compiler doesn't bootstrap with the gcse.c patch you posted earlier in >> the thread? Still this seems too bold to me, the note datum could be a >> constant and should be preserved in this case. > > You mean the patch at > http://gcc.gnu.org/ml/gcc-patches/2012-11/msg02275.html right? > > I haven't tried that other patch. I'll test that one. > ... >> The cse.c hunk is OK then. > > Thanks, I'll commit it separately.
This is what I'll commit in a second. A new proposed cprop.c change will follow later. Ciao! Steven * gcse.c (struct reg_use): Remove unused struct. (gcse_emit_move_after): Do not create REG_EQUAL notes that reference the SET_DEST of the instruction the note would be attached to. * cse.c (cse_main): Add the DF_NOTE problem. Index: gcse.c =================================================================== --- gcse.c (revision 194084) +++ gcse.c (working copy) @@ -255,8 +255,6 @@ int flag_rerun_cse_after_global_opts; /* An obstack for our working variables. */ static struct obstack gcse_obstack; -struct reg_use {rtx reg_rtx; }; - /* Hash table of expressions. */ struct expr @@ -2491,23 +2489,27 @@ gcse_emit_move_after (rtx dest, rtx src, rtx insn) rtx new_rtx; rtx set = single_set (insn), set2; rtx note; - rtx eqv; + rtx eqv = NULL_RTX; /* This should never fail since we're creating a reg->reg copy we've verified to be valid. */ new_rtx = emit_insn_after (gen_move_insn (dest, src), insn); - /* Note the equivalence for local CSE pass. */ + /* Note the equivalence for local CSE pass. Take the note from the old + set if there was one. Otherwise record the SET_SRC from the old set + unless DEST is also an operand of the SET_SRC. */ set2 = single_set (new_rtx); if (!set2 || !rtx_equal_p (SET_DEST (set2), dest)) return new_rtx; if ((note = find_reg_equal_equiv_note (insn))) eqv = XEXP (note, 0); - else + else if (! REG_P (dest) + || ! reg_mentioned_p (dest, SET_SRC (set))) eqv = SET_SRC (set); - set_unique_reg_note (new_rtx, REG_EQUAL, copy_insn_1 (eqv)); + if (eqv != NULL_RTX) + set_unique_reg_note (new_rtx, REG_EQUAL, copy_insn_1 (eqv)); return new_rtx; } Index: cse.c =================================================================== --- cse.c (revision 194084) +++ cse.c (working copy) @@ -6520,6 +6520,7 @@ cse_main (rtx f ATTRIBUTE_UNUSED, int nregs) int i, n_blocks; df_set_flags (DF_LR_RUN_DCE); + df_note_add_problem (); df_analyze (); df_set_flags (DF_DEFER_INSN_RESCAN);