Hi,
Can a gate keeper review the patch to remove unnecessary CHIs introduced by
Lda-Indirect folding? Thank you very much.
The case is like this:
1 int in[10];
2 voif foo(int i) {
3 int *p = in;
4 *p++ = i++;
5 *p++ = i++;
6 *p++ = i++;
7 *p++ = i++;
...
After the Lda-Indirect folding, the HSSA IR is like below:
>LINE 4___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
>OPR_STID I4 I4 sym16v65535 0 <u=0 cr67> b=E3 flags:0x2 pj2 Sid3
// in[0] = i
chi <4/cr21/cr1 14/cr22/cr5 15 17 18 19 > 0x0x80e3090
>LINE 5___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
> LDC U4 1 <u=8187 cr11> flags:0x0 b=-1
> I4ADD <u=1 cr12> isop_flags:0xdc040 flags:0x1 b=E42
>OPR_STID I4 I4 sym17v65535 4 <u=0 cr71> b=E4 flags:0x2 pj2 Sid4
// in[1] = i+1
chi <4/cr32/cr21 14/cr33/cr22 15 16/cr72/cr67 18 19 > 0x0x80e3478
>LINE 6___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
> LDC U4 2 <u=8191 cr54> flags:0x0 b=-1
> I4ADD <u=1 cr55> isop_flags:0xdc040 flags:0x1 b=E47
>OPR_STID I4 I4 sym18v65535 8 <u=0 cr75> b=E5 flags:0x2 pj2 Sid5
// in[2] = i+2
chi <4/cr43/cr32 14/cr44/cr33 15 16/cr76/cr72 17/cr77/cr71 19 > 0x0x80f85b8
>LINE 7___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
> LDC U4 3 <u=8191 cr56> flags:0x0 b=-1
> I4ADD <u=1 cr57> isop_flags:0xdc040 flags:0x1 b=E53
>OPR_STID I4 I4 sym19v65535 12 <u=0 cr79> b=E6 flags:0x2 pj2 Sid6 //
in[3] = i+3
chi <4/cr51/cr43 14/cr52/cr44 15 16/cr80/cr76 17/cr81/cr77 18/cr82/cr75 >
0x0x80f8880
We can find the CHIs in red are unnecessary. Here is the patch:
Index: osprey/be/opt/opt_revise_ssa.cxx
===================================================================
--- osprey/be/opt/opt_revise_ssa.cxx (revision 3556)
+++ osprey/be/opt/opt_revise_ssa.cxx (working copy)
@@ -483,6 +483,7 @@
_symbols_to_revise->Union1D(idx);
AUX_STAB_ENTRY *aux = _opt_stab->Aux_stab_entry(idx);
aux->Points_to()->Set_expr_kind(EXPR_IS_ADDR);
+ aux->Points_to()->Set_ofst_kind(OFST_IS_FIXED);
aux->Points_to()->Set_named();
cr->Set_scalar_aux_id(idx);
@@ -592,6 +593,7 @@
_symbols_to_revise->Union1D(idx);
AUX_STAB_ENTRY *aux = _opt_stab->Aux_stab_entry(idx);
aux->Points_to()->Set_expr_kind(EXPR_IS_ADDR);
+ aux->Points_to()->Set_ofst_kind(OFST_IS_FIXED);
aux->Points_to()->Set_named();
lhs->Set_scalar_aux_id(idx);
When we convert the Lda-Indirect to STID/LDID, new Aux symbols are created
for the STID/LDID.
In the original code, the OFST_IS_FIXED is not set and the alias manager
will treat the new symbols are aliased.
With this patch, the new CODEREP looks like below:
>LINE 4___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
>OPR_STID I4 I4 sym16v65535 0 <u=0 cr67> b=E3 flags:0x2 pj2 Sid3
chi <4/cr21/cr1 14/cr22/cr5 15 > 0x0x80e3090
>LINE 5___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
> LDC U4 1 <u=8187 cr11> flags:0x0 b=-1
> I4ADD <u=1 cr12> isop_flags:0xdc040 flags:0x1 b=E41
>OPR_STID I4 I4 sym17v65535 4 <u=0 cr68> b=E4 flags:0x2 pj2 Sid4
chi <4/cr32/cr21 14/cr33/cr22 15 > 0x0x80e3478
>LINE 6___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
> LDC U4 2 <u=8191 cr54> flags:0x0 b=-1
> I4ADD <u=1 cr55> isop_flags:0xdc040 flags:0x1 b=E44
>OPR_STID I4 I4 sym18v65535 8 <u=0 cr69> b=E5 flags:0x2 pj2 Sid5
chi <4/cr43/cr32 14/cr44/cr33 15 > 0x0x80f85b8
>LINE 7___
> LDID I4 I4 sym1v3 57 ty=402 <u=8189 cr7> flags:0x0 b=V35
> LDC U4 3 <u=8191 cr56> flags:0x0 b=-1
> I4ADD <u=1 cr57> isop_flags:0xdc040 flags:0x1 b=E47
>OPR_STID I4 I4 sym19v65535 12 <u=0 cr70> b=E6 flags:0x2 pj2 Sid6
chi <4/cr51/cr43 14/cr52/cr44 15 > 0x0x80f8880
--
Regards,
Lai Jian-Xin
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