On Sat, Oct 3, 2009 at 12:43 PM, Pranav Bhandarkar <pranav.bhandar...@gmail.com> wrote: > Hi, > > Is it possible for a component_ref node to have its arg 0 to be NULL ? > I would think not because from tree.def I gather that arg 0 tells me > what structures field this component_ref refers to. For convenience, I > have pasted here what tree.def tells me about a component_ref > > > /* Value is structure or union component. > Operand 0 is the structure or union (an expression). > Operand 1 is the field (a node of type FIELD_DECL). > Operand 2, if present, is the value of DECL_FIELD_OFFSET, measured > in units of DECL_OFFSET_ALIGN / BITS_PER_UNIT. */ > DEFTREECODE (COMPONENT_REF, "component_ref", tcc_reference, 3) > > > I am working on a target hook wherein I use the MEM_EXPR of a mem rtx. > It returns the following component_ref node > > <component_ref 0x2b3599d0ca00 > type <integer_type 0x2b35998f1e40 int32 sizes-gimplified public SI > size <integer_cst 0x2b359975a840 constant 32> > unit size <integer_cst 0x2b359975a4b0 constant 4> > align 32 symtab 0 alias set -1 canonical type 0x2b359976d6c0 > precision 32 min <integer_cst 0x2b359975a8a0 -2147483648> max \ > <integer_cst 0x2b359975a8d0 2147483647> > pointer_to_this <pointer_type 0x2b3599b1c300>> > > arg 1 <field_decl 0x2b3599b18140 dcfMemL1 type <integer_type > 0x2b35998f1e40 int32> > used nonlocal decl_3 SI file ../src/synth_core/QDSP6/svrreg.h > line 134 col 11 size <integer_cst 0x2b359975a840 32> unit siz\ > e <integer_cst 0x2b359975a4b0 4> > align 32 offset_align 64 > offset <integer_cst 0x2b3599b04b10 constant 152> bit offset > <integer_cst 0x2b359975a840 32> context <record_type 0x2b3599b1\ > 2840 dlsSvrReg> > chain <field_decl 0x2b3599b181e0 dcfMemL2 type <integer_type > 0x2b35998f1e40 int32> > used nonlocal decl_3 SI file > ../src/synth_core/QDSP6/svrreg.h line 135 col 11 size <integer_cst > 0x2b359975a840 32> unit\ > size <integer_cst 0x2b359975a4b0 4> > align 32 offset_align 64 > offset <integer_cst 0x2b3599b04b70 constant 160> > bit offset <integer_cst 0x2b359977e0c0 constant 0> context > <record_type 0x2b3599b12840 dlsSvrReg> chain <field_decl 0x2\ > b3599b18280 dcfMemR1>>>> > > > Following this if I do > exp = TREE_OPERAND ( comp_ref_node, 0); > > I get "exp" as NULL ? > > Is this possible ? or Is there something I am doing wrong ? or There > is something fishy here with the tree node that MEM_EXPR is giving me > ?
If you are not working on trunk this can happen because the way MEM_EXPRs are "canonicalized". Richard. > Thanks, > Pranav >
