(output_function_{pro,epi}logue): Use addq/subq when adjusting stack

pointer by small displacements.

From-SVN: r13366

diff --git a/gcc/config/m68k/m68k.c b/gcc/config/m68k/m68k.c
index c671c5987e550f9227e19bde47370b68633e0325..029e89c98e26ed1b4ad36302581b2c7286fa4c6c 100644 (file)
--- a/gcc/config/m68k/m68k.c
+++ b/gcc/config/m68k/m68k.c
@@ -1,5 +1,5 @@
 /* Subroutines for insn-output.c for Motorola 68000 family.
-   Copyright (C) 1987, 1993, 1994, 1995, 1996 Free Software Foundation, Inc.
+   Copyright (C) 1987, 93, 94, 95, 96, 1997 Free Software Foundation, Inc.
 
 This file is part of GNU CC.
 
@@ -211,24 +211,61 @@ output_function_prologue (stream, size)
     }
   else if (fsize)
     {
-      /* Adding negative number is faster on the 68040.  */
       if (fsize + 4 < 0x8000)
        {
-         if (!TARGET_68040)
+#ifdef NO_ADDSUB_Q
+         if (fsize + 4 <= 8)
            {
+             if (!TARGET_5200)
+               {
+                 /* asm_fprintf() cannot handle %. */
 #ifdef MOTOROLA
-             asm_fprintf (stream, "\tlea (%d,%Rsp),%Rsp\n", - (fsize + 4));
+                 asm_fprintf (stream, "\tsubq.w %OI%d,%Rsp\n", fsize + 4);
 #else
-             asm_fprintf (stream, "\tlea %Rsp@(%d),%Rsp\n", - (fsize + 4));
+                 asm_fprintf (stream, "\tsubqw %OI%d,%Rsp\n", fsize + 4);
+#endif
+               }
+             else
+               {
+#ifdef MOTOROLA
+                 asm_fprintf (stream, "\tsubq.l %OI%d,%Rsp\n", fsize + 4);
+#else
+                 asm_fprintf (stream, "\tsubql %OI%d,%Rsp\n", fsize + 4);
 #endif
+               }
            }
-         else
+         else if (fsize + 4 <= 16 && TARGET_CPU32)
+           {
+             /* On the CPU32 it is faster to use two subqw instructions to
+                subtract a small integer (8 < N <= 16) to a register. */
+             /* asm_fprintf() cannot handle %. */
+#ifdef MOTOROLA
+             asm_fprintf (stream, "\tsubq.w %OI8,%Rsp\n\tsubq.w %OI%d,%Rsp\n",
+                          fsize + 4);
+#else
+             asm_fprintf (stream, "\tsubqw %OI8,%Rsp\n\tsubqw %OI%d,%Rsp\n",
+                          fsize + 4);
+#endif
+           }
+         else 
+#endif /* NO_ADDSUB_Q */
+         if (TARGET_68040)
            {
+             /* Adding negative number is faster on the 68040.  */
              /* asm_fprintf() cannot handle %. */
 #ifdef MOTOROLA
              asm_fprintf (stream, "\tadd.w %0I%d,%Rsp\n", - (fsize + 4));
 #else
              asm_fprintf (stream, "\taddw %0I%d,%Rsp\n", - (fsize + 4));
+#endif
+           }
+         else
+           {
+             /* asm_fprintf() cannot handle %. */
+#ifdef MOTOROLA
+             asm_fprintf (stream, "\tlea (%d,%Rsp),%Rsp\n", - (fsize + 4));
+#else
+             asm_fprintf (stream, "\tlea %Rsp@(%d),%Rsp\n", - (fsize + 4));
 #endif
            }
        }
@@ -640,23 +677,58 @@ output_function_epilogue (stream, size)
             reg_names[FRAME_POINTER_REGNUM]);
   else if (fsize)
     {
-      if (fsize + 4 < 0x8000)
+#ifdef NO_ADDSUB_Q
+      if (fsize + 4 <= 8) 
        {
-         if (!TARGET_68040)
-           { 
+         if (!TARGET_5200)
+           {
 #ifdef MOTOROLA
-             asm_fprintf (stream, "\tlea (%d,%Rsp),%Rsp\n", fsize + 4);
+             asm_fprintf (stream, "\taddq.w %OI%d,%Rsp\n", fsize + 4);
 #else
-             asm_fprintf (stream, "\tlea %Rsp@(%d),%Rsp\n", fsize + 4);
+             asm_fprintf (stream, "\taddqw %OI%d,%Rsp\n", fsize + 4);
 #endif
            }
          else
            {
+#ifdef MOTOROLA
+             asm_fprintf (stream, "\taddq.l %OI%d,%Rsp\n", fsize + 4);
+#else
+             asm_fprintf (stream, "\taddql %OI%d,%Rsp\n", fsize + 4);
+#endif
+           }
+       }
+      else if (fsize + 4 <= 16 && TARGET_CPU32)
+       {
+         /* On the CPU32 it is faster to use two addqw instructions to
+            add a small integer (8 < N <= 16) to a register. */
+#ifdef MOTOROLA
+         asm_fprintf (stream, "\taddq.w %OI8,%Rsp\n\taddq.w %OI%d,%Rsp\n",
+                      fsize + 4);
+#else
+         asm_fprintf (stream, "\taddqw %OI8,%Rsp\n\taddqw %OI%d,%Rsp\n",
+                      fsize + 4);
+#endif
+       }
+      else
+#endif /* NO_ADDSUB_Q */
+      if (fsize + 4 < 0x8000)
+       {
+         if (TARGET_68040)
+           { 
              /* asm_fprintf() cannot handle %. */
 #ifdef MOTOROLA
              asm_fprintf (stream, "\tadd.w %0I%d,%Rsp\n", fsize + 4);
 #else
              asm_fprintf (stream, "\taddw %0I%d,%Rsp\n", fsize + 4);
+#endif
+           }
+         else
+           {
+             /* asm_fprintf() cannot handle %. */
+#ifdef MOTOROLA
+             asm_fprintf (stream, "\tlea (%d,%Rsp),%Rsp\n", fsize + 4);
+#else
+             asm_fprintf (stream, "\tlea %Rsp@(%d),%Rsp\n", fsize + 4);
 #endif
            }
        }