| Message ID | 201009202330.44434.ebotcazou@adacore.com |
|---|---|
| State | New |
| Headers | show |
On Mon, Sep 20, 2010 at 11:30 PM, Eric Botcazou <ebotcazou@adacore.com> wrote: > 2010-09-20 Eric Botcazou <ebotcazou@adacore.com> > > PR rtl-optimization/42775 > * cfgrtl.c (rest_of_pass_free_cfg): Recompute notes if delay slot > scheduling is enabled. This is in the "egad but what else" category. Qualifies as obvious IMHO. As far as I can tell from the reorg.c source, there are no other DF problems that reorg needs, that have to be recomputed before free'ing the CFG, right? Ciao! Steven
> As far as I can tell from the reorg.c source, there are no other DF > problems that reorg needs, that have to be recomputed before free'ing > the CFG, right? Yes, resource.c should be OK with LR + Notes.
Index: cfgrtl.c =================================================================== --- cfgrtl.c (revision 164451) +++ cfgrtl.c (working copy) @@ -421,7 +421,10 @@ rest_of_pass_free_cfg (void) /* The resource.c machinery uses DF but the CFG isn't guaranteed to be valid at that point so it would be too late to call df_analyze. */ if (optimize > 0 && flag_delayed_branch) - df_analyze (); + { + df_note_add_problem (); + df_analyze (); + } #endif free_bb_for_insn ();
GCC 4.4.x miscompiles itself on the SPARC at -O1, a regression from earlier series. tree-ssa-operands.c:copy_virtual_operands is miscompiled by delay slot scheduling, aka reorg, because of a dangling REG_EQUAL note. cprop_hardreg turns: (insn 287 286 288 39 pr42775.c:19479 (set (reg/v/f:SI 16 %l0 [orig:152 dest_vdefs ] [152]) (reg:SI 8 %o0)) 50 {*movsi_insn} (expr_list:REG_DEAD (reg:SI 8 %o0) (nil))) [...] (insn 348 347 349 48 pr42775.c:19529 (set (reg:SI 1 %g1 [orig:138 ivtmp.1158 ] [138]) (reg/v/f:SI 16 %l0 [orig:152 dest_vdefs ] [152])) 50 {*movsi_insn} (nil)) into: insn 348: replaced reg 16 with 8 (insn 287 286 288 39 pr42775.c:19479 (set (reg/v/f:SI 16 %l0 [orig:152 dest_vdefs ] [152]) (reg:SI 8 %o0)) 50 {*movsi_insn} (expr_list:REG_DEAD (reg:SI 8 %o0) (nil))) [...] (insn 348 347 349 48 pr42775.c:19529 (set (reg:SI 1 %g1 [orig:138 ivtmp.1158 ] [138]) (reg/f:SI 8 %o0 [orig:152 dest_vdefs ] [152])) 50 {*movsi_insn} (nil)) so the REG_DEAD is now wrong and this fools the algorithm in resource.c. Fixed by recomputing notes when reorg is enabled. Bootstrapped/regtested on SPARC64/Linux and SPARC/Solaris, applied on mainline and 4.5/4.4 branches. 2010-09-20 Eric Botcazou <ebotcazou@adacore.com> PR rtl-optimization/42775 * cfgrtl.c (rest_of_pass_free_cfg): Recompute notes if delay slot scheduling is enabled.