sh-mem.cc (sh_expand_strlen): Unroll last word.

2014-04-14  Christian Bruel  <christian.bruel@st.com>

       * config/sh/sh-mem.cc (sh_expand_strlen): Unroll last word.

From-SVN: r209358

gcc/ChangeLog

 2014-04-14  Christian Bruel  <christian.bruel@st.com>
 
+        * config/sh/sh-mem.cc (sh_expand_strlen): Unroll last word.
+
+2014-04-14  Christian Bruel  <christian.bruel@st.com>
+
 	* config/sh/sh.md (setmemqi): New expand pattern.
 	* config/sh/sh.h (CLEAR_RATIO): Define.
 	* config/sh/sh-mem.cc (sh_expand_setmem): Define.

gcc/config/sh/sh-mem.cc

@@ -586,9 +586,35 @@ sh_expand_strlen (rtx *operands)
 
   emit_move_insn (current_addr, plus_constant (Pmode, current_addr, -4));
 
-  /* start byte loop.  */
   addr1 = adjust_address (addr1, QImode, 0);
 
+  /* unroll remaining bytes.  */
+  emit_insn (gen_extendqisi2 (tmp1, addr1));
+  emit_insn (gen_cmpeqsi_t (tmp1, const0_rtx));
+  jump = emit_jump_insn (gen_branch_true (L_return));
+  add_int_reg_note (jump, REG_BR_PROB, prob_likely);
+
+  emit_move_insn (current_addr, plus_constant (Pmode, current_addr, 1));
+
+  emit_insn (gen_extendqisi2 (tmp1, addr1));
+  emit_insn (gen_cmpeqsi_t (tmp1, const0_rtx));
+  jump = emit_jump_insn (gen_branch_true (L_return));
+  add_int_reg_note (jump, REG_BR_PROB, prob_likely);
+
+  emit_move_insn (current_addr, plus_constant (Pmode, current_addr, 1));
+
+  emit_insn (gen_extendqisi2 (tmp1, addr1));
+  emit_insn (gen_cmpeqsi_t (tmp1, const0_rtx));
+  jump = emit_jump_insn (gen_branch_true (L_return));
+  add_int_reg_note (jump, REG_BR_PROB, prob_likely);
+
+  emit_move_insn (current_addr, plus_constant (Pmode, current_addr, 1));
+
+  emit_insn (gen_extendqisi2 (tmp1, addr1));
+  jump = emit_jump_insn (gen_jump_compact (L_return));
+  emit_barrier_after (jump);
+
+  /* start byte loop.  */
   emit_label (L_loop_byte);
 
   emit_insn (gen_extendqisi2 (tmp1, addr1));
@@ -600,10 +626,10 @@ sh_expand_strlen (rtx *operands)
 
   /* end loop.  */
 
-  emit_label (L_return);
-
   emit_insn (gen_addsi3 (start_addr, start_addr, GEN_INT (1)));
 
+  emit_label (L_return);
+
   emit_insn (gen_subsi3 (operands[0], current_addr, start_addr));
 
   return true;