WGEN is not supposed to be an "optimization" phase. For the given phase, VHO might be a good place to eliminate the unreachable case when lowering the switch.
2011/12/7 Yiran Wang <yiran.w...@gmail.com>: > I am not a gatekeeper, but excuse me, I wonder if why not do such kind of > stuff with WGEN. > > Regards, > Yiran > > > On Tue, Dec 6, 2011 at 6:53 PM, Gang Yu <yugang...@gmail.com> wrote: >> >> Hi, >> >> Could a gatekeeper please help review the fix for >> bug798(http://bugs.open64.net/show_bug.cgi?id=798)? >> >> This is a bug for a long time, a typical bug case below: >> >> int defined_fun() >> { >> } >> >> int main() >> { >> >> int t; >> switch(sizeof(t)) >> { >> case 4: >> defined_fun(); >> break; >> default: >> undefined_fun(); >> } >> } >> >> opencc -O0 b.c >> /tmp/cco.c7KVi5: In function `main': >> b.c:15: undefined reference to `undefined_fun' >> >> open64 does not invoke wopt at O0, so call to undefined_fun() is not >> deleted, then the linker asserts. We may have many methods to solve this >> issue, hacking wgen to cut down the unreachable branch, adding special dce >> phase before CG expansion ..... , but the simplest way is to invoke limited >> wopt functionality at O0. >> >> This is inspired by Fred Chow and Previously Sun Chan and Suneel Jain's >> comment on bug588. >> >> >My recommendation would be to do this kind of dead code >> >elimination at -O0 in Open64. That will provide greater compatibility >> >with gcc. >> >- Suneel >> >> >can you do an experiment, please use the following options "-O0 >> >-phase:p" and see if the compile will go through. >> >Thx! >> >Sun >> >> We introduce a special phase q to backend, indicating invoke preopt for >> dce only. the Suggest patch below: >> >> osprey/be/be/driver.cxx -- 207cd21..22e93a8 100644 >> --- a/osprey/be/be/driver.cxx >> +++ b/osprey/be/be/driver.cxx >> @@ -441,6 +441,7 @@ load_components (INT argc, char **argv) >> INT phase_argc; >> char **phase_argv; >> + >> if (!(Run_lno || Run_wopt || Run_preopt || Run_cg || >> Run_prompf || Run_w2c || Run_w2f >> || Run_w2fc_early || Run_ipl)) >> @@ -468,6 +469,10 @@ load_components (INT argc, char **argv) >> CG_Process_Command_Line (phase_argc, phase_argv, argc, argv); >> } >> + /* run preopt for dce only also invoke preopt */ >> + if (Run_preopt_dceonly) >> + Run_preopt = TRUE; >> + >> if (Run_wopt || Run_preopt || Run_lno || Run_autopar) { >> Get_Phase_Args (PHASE_WOPT, &phase_argc, &phase_argv); >> #if !defined(BUILD_FAST_BIN) >> osprey/be/be/driver_util.cxx -- e8f58f9..d5c4698 100644 >> --- a/osprey/be/be/driver_util.cxx >> +++ b/osprey/be/be/driver_util.cxx >> @@ -481,6 +481,12 @@ Process_Command_Line (INT argc, char **argv) >> if (strcmp (myname, "preopt") == 0) >> Run_preopt = TRUE; >> break; >> + case 'q': >> + if (strcmp (myname, "preopt") == 0) { >> + Run_preopt = TRUE; >> + Run_preopt_dceonly = TRUE; >> + } >> + break; >> case 'c': >> if (strcmp (myname, "cg") == 0) >> Run_cg = TRUE; >> osprey/be/opt/opt_main.cxx -- 4b8957c..a7e4679 100644 >> --- a/osprey/be/opt/opt_main.cxx >> +++ b/osprey/be/opt/opt_main.cxx >> @@ -731,6 +731,51 @@ private: >> WOPT_Enable_Combine_Operations = FALSE; >> WOPT_Enable_SLT = FALSE; >> OPT_Enable_WHIRL_SSA = FALSE; >> + if (Run_preopt_dceonly) { >> + WOPT_Enable_Add_Do_Loop_Info = >> + WOPT_Enable_Add_Label_Loop_Info = >> + WOPT_Enable_Aggressive_dce = >> + WOPT_Enable_Aggressive_Code_Motion = >> + WOPT_Enable_Alias_Classification = >> + WOPT_Enable_Alias_Class_Fortran_Rule = >> + WOPT_Enable_Combine_Operations = >> + WOPT_Enable_Compare_Simp = >> + WOPT_Enable_CRSIMP = >> + WOPT_Enable_DCE_Alias = >> + WOPT_Enable_Edge_Placement = >> + WOPT_Enable_Exp_PRE = >> + WOPT_Enable_Fold2const = >> + WOPT_Enable_LNO_Copy_Propagate = >> + WOPT_Enable_FSA = >> + WOPT_Enable_Goto = >> + WOPT_Enable_Input_Prop = >> + WOPT_Enable_Itself_Prop = >> + WOPT_Enable_Ivar_Common = >> + WOPT_Enable_IVE = >> + WOPT_Enable_IVR = >> + WOPT_Enable_Ldx = >> + WOPT_Enable_Load_PRE = >> + WOPT_Enable_Local_Rvi = >> + WOPT_Enable_Output_Copy = >> + WOPT_Enable_Parm = >> + WOPT_Enable_Phi_Simp = >> + WOPT_Enable_RVI = >> + WOPT_Enable_SLT = >> + WOPT_Enable_Store_PRE = >> + WOPT_Enable_SSA_PRE = >> + WOPT_Enable_Vsym_Unique = >> + OPT_Enable_WHIRL_SSA = >> + WOPT_Enable_WOVP = >> + Enable_WN_Simp = // disable WHIRL >> simplifier >> + // WOPT_Enable_Zero_Version = >> + WOPT_Enable_Tail_Recur = >> + FALSE; >> + >> + WOPT_Enable_Verify = 1; >> + WOPT_Enable_DCE = WOPT_Enable_Copy_Propagate = TRUE; >> + >> + >> + } >> break; >> } // switch >> WOPT_Enable_Ldx = Indexed_Loads_Allowed; >> osprey/common/com/config.cxx -- c972676..387f9c1 100644 >> --- a/osprey/common/com/config.cxx >> +++ b/osprey/common/com/config.cxx >> @@ -621,6 +621,8 @@ static OPTION_DESC Options_PHASE[] = { >> &Run_wopt, NULL}, >> { OVK_BOOL, OV_INTERNAL, FALSE, "preopt", "p", 0, 0, 0, >> &Run_preopt, NULL}, >> + { OVK_BOOL, OV_INTERNAL, FALSE, "q", "", 0, 0, 0, >> + &Run_preopt_dceonly, NULL}, >> { OVK_BOOL, OV_INTERNAL, FALSE, "cg", "c", 0, 0, 0, >> &Run_cg, NULL}, >> { OVK_BOOL, OV_INTERNAL, FALSE, "clist", NULL, 0, 0, 0, >> @@ -998,6 +1000,7 @@ BOOL Enable_EBO_Post_Proc_Rgn = TRUE ; >> BOOL Run_lno = FALSE; /* run loop-nest optimizer */ >> BOOL Run_wopt = FALSE; /* run WHIRL global optimizer */ >> BOOL Run_preopt = FALSE; /* run WHIRL preopt optimizer */ >> +BOOL Run_preopt_dceonly = FALSE; /* run WHIRL preopt only for dce >> */ >> BOOL Run_ipl = FALSE; /* run procedure summary phase */ >> BOOL Run_cg = FALSE; /* run code generator */ >> BOOL Run_w2c = FALSE; /* run whirl2c */ >> osprey/common/com/config.h -- 3df7f78..9bdab1d 100644 >> --- a/osprey/common/com/config.h >> +++ b/osprey/common/com/config.h >> @@ -732,6 +732,7 @@ extern BOOL Run_lego; /* run >> lego-lowering */ >> extern BOOL Run_lego_given; /* was run lego-lowering given/not */ >> extern BOOL Run_wopt; /* run WHIRL global optimizer */ >> extern BOOL Run_preopt; /* run WHIRL preopt optimizer >> */ >> +extern BOOL Run_preopt_dceonly; /* run WHIRL preopt only for dce */ >> extern BOOL Run_cg; /* run code generator */ >> extern BOOL Run_w2c; /* run whirl2c */ >> extern BOOL Run_w2f; /* run whirl2f */ >> osprey/driver/special_options.c -- a65a384..abe35f5 100644 >> --- a/osprey/driver/special_options.c >> +++ b/osprey/driver/special_options.c >> @@ -416,13 +416,19 @@ add_special_options (void) >> * >> * -O0/-O1 -O2 -O3 >> * =========================== >> - * .B,.I,.P: cg wopt/cg >> lno/wopt/cg >> - * .N: cg wopt/cg wopt/cg >> + * .B,.I: q/cg wopt/cg >> lno/wopt/cg >> + * .P: cg wopt/cg >> lno/wopt/cg >> + * .N: q/cg wopt/cg wopt/cg >> * .O: cg cg cg >> + * q means preopt for dce only. >> */ >> if (source_kind == S_O) >> warning("compiles of WOPT-generated .O files will usually >> fail due to missing state information"); >> if (olevel <= 1 || source_kind == S_O) >> + if ( source_kind != S_P ) >> + /* bug798 open64.net. add phase q for DCE on O0 .I .B*/ >> + flag = add_string_option(O_PHASE_, "q:c"); >> + else >> flag = add_string_option(O_PHASE_, "c"); >> else if (olevel == 2 || source_kind == S_N) >> flag = add_string_option(O_PHASE_, "w:c"); >> >> could a gatekeeper pleae help a review? thanks >> >> >> Regards >> Gang >> >> >> ------------------------------------------------------------------------------ >> Cloud Services Checklist: Pricing and Packaging Optimization >> This white paper is intended to serve as a reference, checklist and point >> of >> discussion for anyone considering optimizing the pricing and packaging >> model >> of a cloud services business. Read Now! >> http://www.accelacomm.com/jaw/sfnl/114/51491232/ >> _______________________________________________ >> Open64-devel mailing list >> Open64-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/open64-devel >> > > > ------------------------------------------------------------------------------ > Cloud Services Checklist: Pricing and Packaging Optimization > This white paper is intended to serve as a reference, checklist and point of > discussion for anyone considering optimizing the pricing and packaging model > of a cloud services business. Read Now! > http://www.accelacomm.com/jaw/sfnl/114/51491232/ > _______________________________________________ > Open64-devel mailing list > Open64-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/open64-devel > -- Regards, Lai Jian-Xin ------------------------------------------------------------------------------ Cloud Services Checklist: Pricing and Packaging Optimization This white paper is intended to serve as a reference, checklist and point of discussion for anyone considering optimizing the pricing and packaging model of a cloud services business. Read Now! http://www.accelacomm.com/jaw/sfnl/114/51491232/ _______________________________________________ Open64-devel mailing list Open64-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/open64-devel
