Ping 2, and pasted my observation about this ICE, and may someone can help?
The main cause for the ICE is in the function symtab_get_node:
gcc_checking_assert (TREE_CODE (decl) == FUNCTION_DECL
|| (TREE_CODE (decl) == VAR_DECL
&& (TREE_STATIC (decl) || DECL_EXTERNAL (decl)
|| in_lto_p)));
It's a check for the tree attribute for VAR_DECL, but as the register type
variable is neither static nor
external(not sure if this is correct), the compiler will raise ICE here, but in
function
make_decl_rtl(gcc/varasm.c:1357), there's one line comment:
globalize_reg (decl, reg_number + --nregs);
}
/* As a register variable, it has no section. */
return;
}
And for the correct register type declaration like: register int *a asm("r1"),
the program will just directly
return(gcc/varasm.c:1358), and won't sink into the symbol ref generation part.
So symtab_get_node won't be
called.
Currently invalid register type declaration will always sink into the symbol
ref generation part of function
make_decl_rtl, which will also lead to wrong rtx generation.
register int *a asm("r1")=>(reg:SI 1 r1 [orig:0 a] [0])
register int *a asm("unknown register")=>(symbol_ref:SI ("unknown register")
[flag 0x80])
Also the reason that x86 wont't have sunch an ICE is in the code:
if (use_object_blocks_p () && use_blocks_for_decl_p (decl))
x = create_block_symbol (name, get_block_for_decl (decl), -1);
function use_object_blocks_p will always return false on target doesn't support
section anchor, so function
get_block_for_decl which will call symtab_get_node will never be called.
This patch just move the else condition in make_decl_rtl to make all register
type declaration to get the
same rtx, it this a reasonable fix?
> -----Original Message-----
> From: gcc-patches-ow...@gcc.gnu.org [mailto:gcc-patches-ow...@gcc.gnu.org] On
> Behalf Of Tony Wang
> Sent: Tuesday, August 05, 2014 9:35 AM
> To: gcc-patches@gcc.gnu.org
> Cc: 'Richard Biener'; 'Jakub Jelinek'
> Subject: [PING][Patch]Fix ICE for gcc.dg/noncompile/920507-1.c
>
> Ping, any comment and suggestion on this bug fix?
>
> > -----Original Message-----
> > From: gcc-patches-ow...@gcc.gnu.org [mailto:gcc-patches-
> > ow...@gcc.gnu.org] On Behalf Of Tony Wang
> > Sent: Tuesday, July 29, 2014 10:31 AM
> > To: gcc-patches@gcc.gnu.org; 'Richard Biener'; 'Jakub Jelinek'
> > Subject: [Patch]Fix ICE for gcc.dg/noncompile/920507-1.c
> >
> > Hi there,
> >
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61330.
> > There will be an ICE in gcc trunk for targets support section anchor
> > optimization when compiling this case(like arm and mips). This looks like
> an
>
> The target should be aarch64, arm, powerpc, alpha
>
> > old bug which is exposed by recent patch.
> >
> > In make_decl_rtl, when you declare register type incorrectly like
> "register int
> > *a asm("unknown register");", the compiler will raise an error messge but
> > doesn't return directly. It will continue to run into the rtx generation
> code for
> > general variable declaration and generate a wrong rtx:(symbol_ref:SI...).
> So I
> > just remove the else condition which used to be the rtx generation part
> for
> > correctly declared register type, and let all the register type
> declaration(no
> > matter it declared correct or not) go through it and generate the same
> type
> > of rtx:(reg:SI...).
> >
> > gcc/ChangeLog:
> >
> > 2014-07-29 Tony Wang tony.w...@arm.com
> >
> > * gcc/varasm.c (make_decl_rtl): Remove the else condition
> > for properly declared static register variables.
> >
> > diff --git a/gcc/varasm.c b/gcc/varasm.c index 819ec26..a6fae0c 100644
> > --- a/gcc/varasm.c
> > +++ b/gcc/varasm.c
> > @@ -1333,45 +1333,42 @@ make_decl_rtl (tree decl)
> > error ("register specified for %q+D isn%'t suitable for
> data type",
> > decl);
> > /* Now handle properly declared static register variables. */
> > - else
> > - {
> > - int nregs;
> > + int nregs;
> >
> > - if (DECL_INITIAL (decl) != 0 && TREE_STATIC (decl))
> > - {
> > - DECL_INITIAL (decl) = 0;
> > - error ("global register variable has initial value");
> > - }
> > - if (TREE_THIS_VOLATILE (decl))
> > - warning (OPT_Wvolatile_register_var,
> > - "optimization may eliminate reads
> > and/or"
> > - "writes to register variables");
> > + if (DECL_INITIAL (decl) != 0 && TREE_STATIC (decl))
> > + {
> > + DECL_INITIAL (decl) = 0;
> > + error ("global register variable has initial value");
> > + }
> > + if (TREE_THIS_VOLATILE (decl))
> > + warning (OPT_Wvolatile_register_var,
> > + "optimization may eliminate reads and/or "
> > + "writes to register variables");
> >
> > - /* If the user specified one of the eliminables
> > registershere,
> > - e.g., FRAME_POINTER_REGNUM, we don't want to get this
> > variable
> > - confused with that register and be eliminated. This
> > usage is
> > - somewhat suspect... */
> > + /* If the user specified one of the eliminables registers here,
> > + e.g., FRAME_POINTER_REGNUM, we don't want to get this variable
> > + confused with that register and be eliminated. This usage is
> > + somewhat suspect... */
> >
> > - SET_DECL_RTL (decl, gen_rtx_raw_REG (mode, reg_number));
> > - ORIGINAL_REGNO (DECL_RTL (decl)) = reg_number;
> > - REG_USERVAR_P (DECL_RTL (decl)) = 1;
> > + SET_DECL_RTL (decl, gen_rtx_raw_REG (mode, reg_number));
> > + ORIGINAL_REGNO (DECL_RTL (decl)) = reg_number;
> > + REG_USERVAR_P (DECL_RTL (decl)) = 1;
> >
> > - if (TREE_STATIC (decl))
> > - {
> > - /* Make this register global, so not usable for
> > anything
> > - else. */
> > + if (TREE_STATIC (decl))
> > + {
> > + /* Make this register global, so not usable for anything
> > + else. */
> > #ifdef ASM_DECLARE_REGISTER_GLOBAL
> > - name = IDENTIFIER_POINTER (DECL_NAME (decl));
> > - ASM_DECLARE_REGISTER_GLOBAL (asm_out_file, decl,
> > reg_number, name);
> > + name = IDENTIFIER_POINTER (DECL_NAME (decl));
> > + ASM_DECLARE_REGISTER_GLOBAL (asm_out_file, decl, reg_number,
> > name);
> > #endif
> > - nregs = hard_regno_nregs[reg_number][mode];
> > - while (nregs > 0)
> > - globalize_reg (decl, reg_number + --nregs);
> > - }
> > + nregs = hard_regno_nregs[reg_number][mode];
> > + while (nregs > 0)
> > + globalize_reg (decl, reg_number + --nregs);
> > + }
> >
> > - /* As a register variable, it has no section. */
> > - return;
> > - }
> > + /* As a register variable, it has no section. */
> > + return;
> > }
> > /* Now handle ordinary static variables and functions (in memory).
> > Also handle vars declared register invalidly. */
> >
> > BR,
> > Tony
>
>
920507.diff
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