1 files changed, 64 insertions, 31 deletions

diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index 2082cb5..257bce7 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -5346,6 +5346,8 @@ s390_expand_movmem (rtx dst, rtx src, rtx len)
 void
 s390_expand_setmem (rtx dst, rtx len, rtx val)
 {
+  const int very_unlikely = REG_BR_PROB_BASE / 100 - 1;
+
   if (GET_CODE (len) == CONST_INT && INTVAL (len) == 0)
     return;
 
@@ -5391,13 +5393,14 @@ s390_expand_setmem (rtx dst, rtx len, rtx val)
     {
       rtx dst_addr, count, blocks, temp, dstp1 = NULL_RTX;
       rtx_code_label *loop_start_label = gen_label_rtx ();
-      rtx_code_label *loop_end_label = gen_label_rtx ();
-      rtx_code_label *end_label = gen_label_rtx ();
+      rtx_code_label *onebyte_end_label = gen_label_rtx ();
+      rtx_code_label *zerobyte_end_label = gen_label_rtx ();
+      rtx_code_label *restbyte_end_label = gen_label_rtx ();
       machine_mode mode;
 
       mode = GET_MODE (len);
       if (mode == VOIDmode)
-        mode = Pmode;
+	mode = Pmode;
 
       dst_addr = gen_reg_rtx (Pmode);
       count = gen_reg_rtx (mode);
@@ -5405,39 +5408,56 @@ s390_expand_setmem (rtx dst, rtx len, rtx val)
 
       convert_move (count, len, 1);
       emit_cmp_and_jump_insns (count, const0_rtx,
-			       EQ, NULL_RTX, mode, 1, end_label);
+			       EQ, NULL_RTX, mode, 1, zerobyte_end_label,
+			       very_unlikely);
 
+      /* We need to make a copy of the target address since memset is
+	 supposed to return it unmodified.  We have to make it here
+	 already since the new reg is used at onebyte_end_label.  */
       emit_move_insn (dst_addr, force_operand (XEXP (dst, 0), NULL_RTX));
       dst = change_address (dst, VOIDmode, dst_addr);
 
-      if (val == const0_rtx)
-        temp = expand_binop (mode, add_optab, count, constm1_rtx, count, 1,
-			     OPTAB_DIRECT);
-      else
+      if (val != const0_rtx)
 	{
-	  dstp1 = adjust_address (dst, VOIDmode, 1);
+	  /* When using the overlapping mvc the original target
+	     address is only accessed as single byte entity (even by
+	     the mvc reading this value).  */
 	  set_mem_size (dst, 1);
-
-	  /* Initialize memory by storing the first byte.  */
-	  emit_move_insn (adjust_address (dst, QImode, 0), val);
-
-	  /* If count is 1 we are done.  */
-	  emit_cmp_and_jump_insns (count, const1_rtx,
-				   EQ, NULL_RTX, mode, 1, end_label);
-
-	  temp = expand_binop (mode, add_optab, count, GEN_INT (-2), count, 1,
-			       OPTAB_DIRECT);
-	}
+	  dstp1 = adjust_address (dst, VOIDmode, 1);
+	  emit_cmp_and_jump_insns (count,
+				   const1_rtx, EQ, NULL_RTX, mode, 1,
+				   onebyte_end_label, very_unlikely);
+	}
+
+      /* There is one unconditional (mvi+mvc)/xc after the loop
+	 dealing with the rest of the bytes, subtracting two (mvi+mvc)
+	 or one (xc) here leaves this number of bytes to be handled by
+	 it.  */
+      temp = expand_binop (mode, add_optab, count,
+			   val == const0_rtx ? constm1_rtx : GEN_INT (-2),
+			   count, 1, OPTAB_DIRECT);
       if (temp != count)
-        emit_move_insn (count, temp);
+	emit_move_insn (count, temp);
 
       temp = expand_binop (mode, lshr_optab, count, GEN_INT (8), blocks, 1,
 			   OPTAB_DIRECT);
       if (temp != blocks)
-        emit_move_insn (blocks, temp);
+	emit_move_insn (blocks, temp);
 
       emit_cmp_and_jump_insns (blocks, const0_rtx,
-			       EQ, NULL_RTX, mode, 1, loop_end_label);
+			       EQ, NULL_RTX, mode, 1, restbyte_end_label);
+
+      emit_jump (loop_start_label);
+
+      if (val != const0_rtx)
+	{
+	  /* The 1 byte != 0 special case.  Not handled efficiently
+	     since we require two jumps for that.  However, this
+	     should be very rare.  */
+	  emit_label (onebyte_end_label);
+	  emit_move_insn (adjust_address (dst, QImode, 0), val);
+	  emit_jump (zerobyte_end_label);
+	}
 
       emit_label (loop_start_label);
 
@@ -5455,26 +5475,39 @@ s390_expand_setmem (rtx dst, rtx len, rtx val)
       if (val == const0_rtx)
 	emit_insn (gen_clrmem_short (dst, GEN_INT (255)));
       else
-	emit_insn (gen_movmem_short (dstp1, dst, GEN_INT (255)));
+	{
+	  /* Set the first byte in the block to the value and use an
+	     overlapping mvc for the block.  */
+	  emit_move_insn (adjust_address (dst, QImode, 0), val);
+	  emit_insn (gen_movmem_short (dstp1, dst, GEN_INT (254)));
+	}
       s390_load_address (dst_addr,
 			 gen_rtx_PLUS (Pmode, dst_addr, GEN_INT (256)));
 
       temp = expand_binop (mode, add_optab, blocks, constm1_rtx, blocks, 1,
 			   OPTAB_DIRECT);
       if (temp != blocks)
-        emit_move_insn (blocks, temp);
+	emit_move_insn (blocks, temp);
 
       emit_cmp_and_jump_insns (blocks, const0_rtx,
-			       EQ, NULL_RTX, mode, 1, loop_end_label);
+			       NE, NULL_RTX, mode, 1, loop_start_label);
 
-      emit_jump (loop_start_label);
-      emit_label (loop_end_label);
+      emit_label (restbyte_end_label);
 
       if (val == const0_rtx)
-        emit_insn (gen_clrmem_short (dst, convert_to_mode (Pmode, count, 1)));
+	emit_insn (gen_clrmem_short (dst, convert_to_mode (Pmode, count, 1)));
       else
-        emit_insn (gen_movmem_short (dstp1, dst, convert_to_mode (Pmode, count, 1)));
-      emit_label (end_label);
+	{
+	  /* Set the first byte in the block to the value and use an
+	     overlapping mvc for the block.  */
+	  emit_move_insn (adjust_address (dst, QImode, 0), val);
+	  /* execute only uses the lowest 8 bits of count that's
+	     exactly what we need here.  */
+	  emit_insn (gen_movmem_short (dstp1, dst,
+				       convert_to_mode (Pmode, count, 1)));
+	}
+
+      emit_label (zerobyte_end_label);
     }
 }