Improve SImode shifts for H8

Similar to the H8/300H patch, this improves SImode shifts for the H8/S.
It's not as big a win on the H8/S since we can shift two positions at a
time.  But that also means that we can handle more residuals with minimal
ode growth after a special shift-by-16 or shift-by-24 sequence.

I think there's more to do here, but this seemed like as good a checkpoint
as any.  Tested without regressions.

gcc/
	* config/h8300/h8300.c (shift_alg_si): Avoid loops for most SImode
	shifts on the H8/S.
	(h8300_option_override): Use loops on H8/S more often when optimizing
	for size.
	(get_shift_alg): Handle new "special" cases on H8/S.  Simplify
	accordingly.  Handle various arithmetic right shifts with special
	sequences that we couldn't handle before.

diff --git a/gcc/config/h8300/h8300.c b/gcc/config/h8300/h8300.c
index 7959ad1..0c4e508 100644 (file)
--- a/gcc/config/h8300/h8300.c
+++ b/gcc/config/h8300/h8300.c
@@ -248,17 +248,17 @@ static enum shift_alg shift_alg_si[2][3][32] = {
     /* 16   17   18   19   20   21   22   23  */
     /* 24   25   26   27   28   29   30   31  */
     { INL, INL, INL, INL, INL, INL, INL, INL,
-      INL, INL, INL, LOP, LOP, LOP, LOP, SPC,
-      SPC, SPC, SPC, SPC, SPC, SPC, LOP, LOP,
-      SPC, SPC, LOP, LOP, SPC, SPC, SPC, SPC }, /* SHIFT_ASHIFT   */
+      INL, INL, INL, INL, INL, INL, INL, SPC,
+      SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC,
+      SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC }, /* SHIFT_ASHIFT   */
     { INL, INL, INL, INL, INL, INL, INL, INL,
-      INL, INL, INL, LOP, LOP, LOP, LOP, SPC,
-      SPC, SPC, SPC, SPC, SPC, SPC, LOP, LOP,
-      SPC, SPC, LOP, LOP, SPC, SPC, SPC, SPC }, /* SHIFT_LSHIFTRT */
+      INL, INL, INL, INL, INL, INL, INL, SPC,
+      SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC,
+      SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC }, /* SHIFT_LSHIFTRT */
     { INL, INL, INL, INL, INL, INL, INL, INL,
-      INL, INL, INL, LOP, LOP, LOP, LOP, LOP,
-      SPC, SPC, SPC, SPC, SPC, SPC, LOP, LOP,
-      SPC, SPC, LOP, LOP, LOP, LOP, LOP, SPC }, /* SHIFT_ASHIFTRT */
+      INL, INL, INL, INL, INL, INL, INL, LOP,
+      SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC,
+      SPC, SPC, SPC, SPC, SPC, SPC, SPC, SPC }, /* SHIFT_ASHIFTRT */
   }
 };
 
@@ -375,6 +375,36 @@ h8300_option_override (void)
 
       /* H8S */
       shift_alg_hi[H8_S][SHIFT_ASHIFTRT][14] = SHIFT_LOOP;
+
+      shift_alg_si[H8_S][SHIFT_ASHIFT][11] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][12] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][13] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][14] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][22] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][23] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][26] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFT][27] = SHIFT_LOOP;
+
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][11] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][12] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][13] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][14] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][22] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][23] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][26] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_LSHIFTRT][27] = SHIFT_LOOP;
+
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][11] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][12] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][13] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][14] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][22] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][23] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][26] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][27] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][28] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][29] = SHIFT_LOOP;
+      shift_alg_si[H8_S][SHIFT_ASHIFTRT][30] = SHIFT_LOOP;
     }
 
   /* Work out a value for MOVE_RATIO.  */
@@ -3814,8 +3844,7 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
              gcc_unreachable ();
            }
        }
-      else if ((TARGET_H8300H && count >= 16 && count <= 23)
-              || (TARGET_H8300S && count >= 16 && count <= 21))
+      else if (count >= 16 && count <= 23)
        {
          info->remainder = count - 16;
 
@@ -3834,8 +3863,7 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
              goto end;
            }
        }
-      else if ((TARGET_H8300H && count >= 24 || count <= 27)
-              || (TARGET_H8300S && count >= 24 && count <= 25))
+      else if (count >= 24 && count <= 27)
        {
          info->remainder = count - 24;
 
@@ -3874,7 +3902,10 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
                info->special = "sub.w\t%f0,%f0\n\trotl.l\t#2,%S0\n\trotl.l\t#2,%S0\n\textu.l\t%S0";
              goto end;
            case SHIFT_ASHIFTRT:
-             gcc_unreachable ();
+             info->remainder = count - 24;
+             info->special = "mov.w\t%e0,%f0\n\tmov.b\t%t0,%s0\n\texts.w\t%f0\n\texts.l\t%S0";
+             info->cc_special = OLD_CC_SET_ZNV;
+             goto end;
            }
        }
       else if (count == 29)
@@ -3900,7 +3931,10 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
                }
              goto end;
            case SHIFT_ASHIFTRT:
-             gcc_unreachable ();
+             info->remainder = count - 24;
+             info->special = "mov.w\t%e0,%f0\n\tmov.b\t%t0,%s0\n\texts.w\t%f0\n\texts.l\t%S0";
+             info->cc_special = OLD_CC_SET_ZNV;
+             goto end;
            }
        }
       else if (count == 30)
@@ -3920,7 +3954,10 @@ get_shift_alg (enum shift_type shift_type, enum shift_mode shift_mode,
                info->special = "sub.w\t%f0,%f0\n\trotl.l\t#2,%S0\n\textu.l\t%S0";
              goto end;
            case SHIFT_ASHIFTRT:
-             gcc_unreachable ();
+             info->remainder = count - 24;
+             info->special = "mov.w\t%e0,%f0\n\tmov.b\t%t0,%s0\n\texts.w\t%f0\n\texts.l\t%S0";
+             info->cc_special = OLD_CC_SET_ZNV;
+             goto end;
            }
        }
       else if (count == 31)