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Re: [patch][DF] fix df_find_def and df_find_use


Il 10/04/2013 21:33, Steven Bosscher ha scritto:
> Hello,
> 
> df_find_def and df_find_use do not work properly for hard registers
> because rtx_equal_p returns false for the case where
> REGNO(x)==REGNO(y) but the modes are different. This happened as
> follows in my case:
> 
> Breakpoint 9, df_reg_used (insn=0x3fffb6083c50, reg=0x3fffb5eb72e0) at
> ../../trunk/gcc/df-core.c:1856
> 1856      return df_find_use (insn, reg) != NULL;
> (gdb) p debug_rtx(reg)
> (reg:CCX 100 %icc)
> $37 = void
> (gdb) p debug_rtx(insn)
> (jump_insn 34 33 35 3 (set (pc)
>         (if_then_else (le (reg:CCX 100 %icc)
>                 (const_int 0 [0]))
>             (label_ref 44)
>             (pc))) t.c:25 48 {*normal_branch}
>      (expr_list:REG_DEAD (reg:CCX 100 %icc)
>         (expr_list:REG_BR_PROB (const_int 3900 [0xf3c])
>             (nil)))
>  -> 44)
> $38 = void
> (gdb) step
> df_find_use (insn=0x3fffb6083c50, reg=0x3fffb5eb72e0) at
> ../../trunk/gcc/df-core.c:1829
> ...
> 1837          if (rtx_equal_p (DF_REF_REAL_REG (use), reg))
> (gdb) p debug_rtx(reg)
> (reg:CCX 100 %icc)
> $39 = void
> (gdb) p debug_rtx(DF_REF_REAL_REG(use))
> (reg:CC 100 %icc)
> $40 = void
> (gdb) p rtx_equal_p (DF_REF_REAL_REG (use), reg)
> $41 = 0
> 
> 
> I think we should just compare REGNO instead of going through rtx_equal_p.
> 
> Bootstrapped&tested on x86_64-unknown-linux-gnu.
> OK for trunk?

Ok.  Was this with out-of-tree patches?

Paolo

> Ciao!
> Steven
> 
> 
> 
>         * df-core.c (df_find_def): Compare register numbers.
>         (df_find_use): Compare register numbers.
> 
> Index: df-core.c
> ===================================================================
> --- df-core.c   (revision 197610)
> +++ df-core.c   (working copy)
> @@ -1800,7 +1800,7 @@ df_find_def (rtx insn, rtx reg)
>    for (def_rec = DF_INSN_UID_DEFS (uid); *def_rec; def_rec++)
>      {
>        df_ref def = *def_rec;
> -      if (rtx_equal_p (DF_REF_REAL_REG (def), reg))
> +      if (DF_REF_REGNO (def) == REGNO (reg))
>         return def;
>      }
> 
> @@ -1834,14 +1834,14 @@ df_find_use (rtx insn, rtx reg)
>    for (use_rec = DF_INSN_UID_USES (uid); *use_rec; use_rec++)
>      {
>        df_ref use = *use_rec;
> -      if (rtx_equal_p (DF_REF_REAL_REG (use), reg))
> +      if (DF_REF_REGNO (use) == REGNO (reg))
>         return use;
>      }
>    if (df->changeable_flags & DF_EQ_NOTES)
>      for (use_rec = DF_INSN_UID_EQ_USES (uid); *use_rec; use_rec++)
>        {
>         df_ref use = *use_rec;
> -       if (rtx_equal_p (DF_REF_REAL_REG (use), reg))
> +       if (DF_REF_REGNO (use) == REGNO (reg))
>           return use;
>        }
>    return NULL;
> 


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