re PR target/53975 ([ia64] Target register of a speculative load moved to a…

re PR target/53975 ([ia64] Target register of a speculative load moved to a branch register prior to the chk.s instruction)

        PR target/53975

        * sel-sched-ir.c (has_dependence_note_reg_use): Clarify comment.

        Revert
        2011-08-04  Sergey Grechanik  <mouseentity@ispras.ru>

        * sel-sched-ir.c (has_dependence_note_reg_use): Call ds_full_merge
        only if producer writes to the register given by regno.

From-SVN: r190005

gcc/ChangeLog

+2012-07-31  Andrey Belevantsev  <abel@ispras.ru>
+
+	PR target/53975
+	
+	* sel-sched-ir.c (has_dependence_note_reg_use): Clarify comment. 
+
+	Revert
+	2011-08-04  Sergey Grechanik  <mouseentity@ispras.ru>
+
+	* sel-sched-ir.c (has_dependence_note_reg_use): Call ds_full_merge
+	only if producer writes to the register given by regno.
+
 2012-07-31  Nick Clifton  <nickc@redhat.com>
 
 	* config/frv/frv.c (QUAD): Fix typo.

gcc/sel-sched-ir.c

@@ -3228,7 +3228,11 @@ has_dependence_note_reg_use (int regno)
       if (reg_last->clobbers)
 	*dsp = (*dsp & ~SPECULATIVE) | DEP_ANTI;
 
-      /* Handle BE_IN_SPEC.  */
+      /* Merge BE_IN_SPEC bits into *DSP when the dependency producer
+	 is actually a check insn.  We need to do this for any register
+	 read-read dependency with the check unless we track properly
+	 all registers written by BE_IN_SPEC-speculated insns, as
+	 we don't have explicit dependence lists.  See PR 53975.  */
       if (reg_last->uses)
 	{
 	  ds_t pro_spec_checked_ds;
@@ -3236,9 +3240,7 @@ has_dependence_note_reg_use (int regno)
 	  pro_spec_checked_ds = INSN_SPEC_CHECKED_DS (has_dependence_data.pro);
 	  pro_spec_checked_ds = ds_get_max_dep_weak (pro_spec_checked_ds);
 
-	  if (pro_spec_checked_ds != 0
-	      && bitmap_bit_p (INSN_REG_SETS (has_dependence_data.pro), regno))
-	    /* Merge BE_IN_SPEC bits into *DSP.  */
+	  if (pro_spec_checked_ds != 0)
 	    *dsp = ds_full_merge (*dsp, pro_spec_checked_ds,
 				  NULL_RTX, NULL_RTX);
 	}