This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] Fix PR 55889


On 19.02.2013 17:13, Andrey Belevantsev wrote:
Hello,

As we discussed in the PR, the problem here is that the selective scheduler
does not expect that renaming a hard register to a pseudo would result in
extra dependencies.  The dependencies come from implicit clobbers code of
sched-deps.c, so I've made a minimal patch that checks only for that case
using the same function from IRA and avoids it.

The patch fixes the test case on AIX as reported by David and also
bootstraps and tests fine on x86-64 and ia64, ok for trunk?

The second patch is restoring debug printing in the scheduler that was
accidentally broken, possibly by Steven's cleanups (now a pattern is
expected where an insn was previously).  I will commit is as obvious
separately.

Andrey

2012-02-19  Andrey Belevantsev  <abel@ispras.ru>

     PR middle-end/55889

     * sel-sched.c: Include ira.h.
     (implicit_clobber_conflict_p): New function.
     (moveup_expr): Use it.
     * Makefile.in (sel-sched.o): Depend on ira.h.


Now backported this to 4.7 and 4.6.

Andrey

Index: gcc/ChangeLog
===================================================================
*** gcc/ChangeLog	(revision 197297)
--- gcc/ChangeLog	(revision 197298)
***************
*** 1,6 ****
--- 1,18 ----
  2013-04-01  Andrey Belevantsev  <abel@ispras.ru>
  
  	Backport from mainline
+ 	2012-02-19  Andrey Belevantsev  <abel@ispras.ru>
+ 
+ 	PR middle-end/55889
+ 
+ 	* sel-sched.c: Include ira.h.
+ 	(implicit_clobber_conflict_p): New function.
+ 	(moveup_expr): Use it.
+ 	* Makefile.in (sel-sched.o): Depend on ira.h. 
+ 
+ 2013-04-01  Andrey Belevantsev  <abel@ispras.ru>
+ 
+ 	Backport from mainline
  	2013-02-25  Andrey Belevantsev  <abel@ispras.ru>
  	Alexander Monakov  <amonakov@ispras.ru>
  
Index: gcc/sel-sched.c
===================================================================
*** gcc/sel-sched.c	(revision 197297)
--- gcc/sel-sched.c	(revision 197298)
*************** along with GCC; see the file COPYING3.  
*** 45,50 ****
--- 45,51 ----
  #include "rtlhooks-def.h"
  #include "output.h"
  #include "emit-rtl.h"
+ #include "ira.h"
  
  #ifdef INSN_SCHEDULING
  #include "sel-sched-ir.h"
*************** moving_insn_creates_bookkeeping_block_p 
*** 2113,2118 ****
--- 2114,2174 ----
    return TRUE;
  }
  
+ /* Return true when the conflict with newly created implicit clobbers
+    between EXPR and THROUGH_INSN is found because of renaming.  */
+ static bool
+ implicit_clobber_conflict_p (insn_t through_insn, expr_t expr)
+ {
+   HARD_REG_SET temp;
+   rtx insn, reg, rhs, pat;
+   hard_reg_set_iterator hrsi;
+   unsigned regno;
+   bool valid;
+ 
+   /* Make a new pseudo register.  */
+   reg = gen_reg_rtx (GET_MODE (EXPR_LHS (expr)));
+   max_regno = max_reg_num ();
+   maybe_extend_reg_info_p ();
+ 
+   /* Validate a change and bail out early.  */
+   insn = EXPR_INSN_RTX (expr);
+   validate_change (insn, &SET_DEST (PATTERN (insn)), reg, true);
+   valid = verify_changes (0);
+   cancel_changes (0);
+   if (!valid)
+     {
+       if (sched_verbose >= 6)
+ 	sel_print ("implicit clobbers failed validation, ");
+       return true;
+     }
+ 
+   /* Make a new insn with it.  */
+   rhs = copy_rtx (VINSN_RHS (EXPR_VINSN (expr)));
+   pat = gen_rtx_SET (VOIDmode, reg, rhs);
+   start_sequence ();
+   insn = emit_insn (pat);
+   end_sequence ();
+ 
+   /* Calculate implicit clobbers.  */
+   extract_insn (insn);
+   preprocess_constraints ();
+   ira_implicitly_set_insn_hard_regs (&temp);
+   AND_COMPL_HARD_REG_SET (temp, ira_no_alloc_regs);
+ 
+   /* If any implicit clobber registers intersect with regular ones in
+      through_insn, we have a dependency and thus bail out.  */
+   EXECUTE_IF_SET_IN_HARD_REG_SET (temp, 0, regno, hrsi)
+     {
+       vinsn_t vi = INSN_VINSN (through_insn);
+       if (bitmap_bit_p (VINSN_REG_SETS (vi), regno)
+ 	  || bitmap_bit_p (VINSN_REG_CLOBBERS (vi), regno)
+ 	  || bitmap_bit_p (VINSN_REG_USES (vi), regno))
+ 	return true;
+     }
+ 
+   return false;
+ }
+ 
  /* Modifies EXPR so it can be moved through the THROUGH_INSN,
     performing necessary transformations.  Record the type of transformation
     made in PTRANS_TYPE, when it is not NULL.  When INSIDE_INSN_GROUP,
*************** moveup_expr (expr_t expr, insn_t through
*** 2245,2250 ****
--- 2301,2317 ----
        if (!enable_schedule_as_rhs_p || !EXPR_SEPARABLE_P (expr))
          return MOVEUP_EXPR_NULL;
  
+       /* When renaming a hard register to a pseudo before reload, extra
+ 	 dependencies can occur from the implicit clobbers of the insn.
+ 	 Filter out such cases here.  */
+       if (!reload_completed && REG_P (EXPR_LHS (expr))
+ 	  && HARD_REGISTER_P (EXPR_LHS (expr))
+ 	  && implicit_clobber_conflict_p (through_insn, expr))
+ 	{
+ 	  if (sched_verbose >= 6)
+ 	    sel_print ("implicit clobbers conflict detected, ");
+ 	  return MOVEUP_EXPR_NULL;
+ 	}
        EXPR_TARGET_AVAILABLE (expr) = false;
        was_target_conflict = true;
        as_rhs = true;
Index: gcc/Makefile.in
===================================================================
*** gcc/Makefile.in	(revision 197297)
--- gcc/Makefile.in	(revision 197298)
*************** sel-sched.o : sel-sched.c $(CONFIG_H) $(
*** 3366,3372 ****
     $(FUNCTION_H) $(INSN_ATTR_H)  $(RECOG_H) $(EXCEPT_H) $(PARAMS_H) \
     $(TM_P_H) output.h $(TARGET_H) $(TIMEVAR_H) $(TREE_PASS_H)  \
     $(SCHED_INT_H) $(GGC_H) $(TREE_H) langhooks.h rtlhooks-def.h \
!    $(SEL_SCHED_IR_H) $(SEL_SCHED_DUMP_H) sel-sched.h $(DBGCNT_H) $(EMIT_RTL_H)
  sel-sched-dump.o : sel-sched-dump.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
     $(RTL_H) $(REGS_H) hard-reg-set.h $(FLAGS_H) insn-config.h \
     $(FUNCTION_H) $(INSN_ATTR_H) $(DIAGNOSTIC_CORE_H) $(RECOG_H) $(EXCEPT_H) $(PARAMS_H) \
--- 3366,3372 ----
     $(FUNCTION_H) $(INSN_ATTR_H)  $(RECOG_H) $(EXCEPT_H) $(PARAMS_H) \
     $(TM_P_H) output.h $(TARGET_H) $(TIMEVAR_H) $(TREE_PASS_H)  \
     $(SCHED_INT_H) $(GGC_H) $(TREE_H) langhooks.h rtlhooks-def.h \
!    $(SEL_SCHED_IR_H) $(SEL_SCHED_DUMP_H) sel-sched.h $(DBGCNT_H) $(EMIT_RTL_H) ira.h
  sel-sched-dump.o : sel-sched-dump.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) \
     $(RTL_H) $(REGS_H) hard-reg-set.h $(FLAGS_H) insn-config.h \
     $(FUNCTION_H) $(INSN_ATTR_H) $(DIAGNOSTIC_CORE_H) $(RECOG_H) $(EXCEPT_H) $(PARAMS_H) \

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]