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Re: Abt RTL expression
- From: Revital1 Eres <ERES at il dot ibm dot com>
- To: "Rohit Arul Raj" <rohitarulraj at gmail dot com>
- Cc: gcc at gcc dot gnu dot org
- Date: Mon, 23 Oct 2006 11:17:58 +0200
- Subject: Re: Abt RTL expression
> a) To which register is the value of n copied? if a5 is the register
> what is 13 and [28]
All of those numbers refer to the same register -
13 is the number of the register; a5 is the name of the register
(if it is an hard register);
[28] is the number of the old pseudo register.
(please look at ORIGINAL_REGNO in rtl.h for more info)
> b) what is [flags 0x2] <var_decl 0x40227160 n>
[flags 0x2] are symbol_ref flags and var_decl is the tree decl associated
with this symbol.
(see SYMBOL_REF_FLAGS in rtl.h)
>
> 2.(insn 12 11 13 0 gcc/testsuite/gcc.c-torture/execute/20020611-1.c:13
> (set (reg:SI 0 d0 [orig:29 n ] [29])
> (mem/c/i:SI (reg/f:SI 13 a5 [28]) [2 n+0 S4 A32])) 15
> {movsi_load} (insn_list:REG_DEP_TRUE 11 (nil))
> (expr_list:REG_DEAD (reg/f:SI 13 a5 [28])
> (expr_list:REG_EQUAL (mem/c/i:SI (symbol_ref:SI ("n") [flags
> 0x2] <var_decl 0x40227160 n>) [2 n+0 S4 A32])
> (nil))))
>
> a) what does this mean [orig:29 n ] [29] in the above expression?
As above; [orig:29 n ] [29] are the numbers of the old
pseudo register.
> b) what does this mean [2 n+0 S4 A32] in the above expression?
[2 n+0 S4 A32] contains information on the memory expression -
2 is the alias set (MEM_ALIAS_SET);n is the base memory expression and 0 is
it's offset
;S4 is the size in bytes of the memory expression (MEM_SIZE) and A32 is the
alignment in bits (MEM_ALIGN).
Hope it helps,
Revital