PR rtl-optimization/58662

	* combine.c (try_combine): Take into account death nodes on I2 when
	splitting a PARALLEL of two independent SETs.  Fix dump message.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@203498 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 27 insertions, 16 deletions

diff --git a/gcc/combine.c b/gcc/combine.c
index fcf60cd08aa..13f5e29e3d6 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -3693,29 +3693,42 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p,
 	   && ! (contains_muldiv (SET_SRC (XVECEXP (newpat, 0, 0)))
 		 && contains_muldiv (SET_SRC (XVECEXP (newpat, 0, 1)))))
     {
+      rtx set0 = XVECEXP (newpat, 0, 0);
+      rtx set1 = XVECEXP (newpat, 0, 1);
+
       /* Normally, it doesn't matter which of the two is done first,
 	 but the one that references cc0 can't be the second, and
 	 one which uses any regs/memory set in between i2 and i3 can't
-	 be first.  */
-      if (!use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 1)),
-			      DF_INSN_LUID (i2))
+	 be first.  The PARALLEL might also have been pre-existing in i3,
+	 so we need to make sure that we won't wrongly hoist a SET to i2
+	 that would conflict with a death note present in there.  */
+      if (!use_crosses_set_p (SET_SRC (set1), DF_INSN_LUID (i2))
+	  && !(REG_P (SET_DEST (set1))
+	       && find_reg_note (i2, REG_DEAD, SET_DEST (set1)))
+	  && !(GET_CODE (SET_DEST (set1)) == SUBREG
+	       && find_reg_note (i2, REG_DEAD,
+				 SUBREG_REG (SET_DEST (set1))))
 #ifdef HAVE_cc0
-	  && !reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 0))
+	  && !reg_referenced_p (cc0_rtx, set0)
 #endif
 	 )
 	{
-	  newi2pat = XVECEXP (newpat, 0, 1);
-	  newpat = XVECEXP (newpat, 0, 0);
+	  newi2pat = set1;
+	  newpat = set0;
 	}
-      else if (!use_crosses_set_p (SET_SRC (XVECEXP (newpat, 0, 0)),
-				   DF_INSN_LUID (i2))
+      else if (!use_crosses_set_p (SET_SRC (set0), DF_INSN_LUID (i2))
+	       && !(REG_P (SET_DEST (set0))
+		    && find_reg_note (i2, REG_DEAD, SET_DEST (set0)))
+	       && !(GET_CODE (SET_DEST (set0)) == SUBREG
+		    && find_reg_note (i2, REG_DEAD,
+				      SUBREG_REG (SET_DEST (set0))))
 #ifdef HAVE_cc0
-	       && !reg_referenced_p (cc0_rtx, XVECEXP (newpat, 0, 1))
+	       && !reg_referenced_p (cc0_rtx, set1)
 #endif
 	      )
 	{
-	  newi2pat = XVECEXP (newpat, 0, 0);
-	  newpat = XVECEXP (newpat, 0, 1);
+	  newi2pat = set0;
+	  newpat = set1;
 	}
       else
 	{
@@ -4261,9 +4274,8 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p,
       }
 
     /* Update reg_stat[].nonzero_bits et al for any changes that may have
-       been made to this insn.  The order of
-       set_nonzero_bits_and_sign_copies() is important.  Because newi2pat
-       can affect nonzero_bits of newpat */
+       been made to this insn.  The order is important, because newi2pat
+       can affect nonzero_bits of newpat.  */
     if (newi2pat)
       note_stores (newi2pat, set_nonzero_bits_and_sign_copies, NULL);
     note_stores (newpat, set_nonzero_bits_and_sign_copies, NULL);
@@ -4283,7 +4295,7 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p,
     {
       if (dump_file)
 	{
-	  fprintf (dump_file, "modifying insn i1 ");
+	  fprintf (dump_file, "modifying insn i0 ");
 	  dump_insn_slim (dump_file, i0);
 	}
       df_insn_rescan (i0);
@@ -4321,7 +4333,6 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int *new_direct_jump_p,
 
   /* Set new_direct_jump_p if a new return or simple jump instruction
      has been created.  Adjust the CFG accordingly.  */
-
   if (returnjump_p (i3) || any_uncondjump_p (i3))
     {
       *new_direct_jump_p = 1;