expr.c: Corrected comment about what MOVE_RATIO does.

        * expr.c: Corrected comment about what MOVE_RATIO does.
        * config/alpha/alpha.h: Ditto.
        * config/1750a/1750a.h: Ditto.
        * config/clipper/clipper.h: Ditto.
        * config/i386/i386.h: Ditto.

From-SVN: r22339

gcc/ChangeLog

+Tue Sep  8 23:46:04 1998  Hans-Peter Nilsson  <hp@axis.se>
+
+	* expr.c: Corrected comment about what MOVE_RATIO does.
+	* config/alpha/alpha.h: Ditto.
+	* config/1750a/1750a.h: Ditto.
+	* config/clipper/clipper.h: Ditto.
+	* config/i386/i386.h: Ditto.
+
 Tue Sep  8 22:56:12 1998  Jeffrey A Law  (law@cygnus.com)
 
 	* configure.in (m68k-next-nextstep3*): Use collect2.

gcc/config/1750a/1750a.h

@@ -854,8 +854,8 @@ enum reg_class { NO_REGS, R2, R0_1, INDEX_REGS, BASE_REGS, ALL_REGS, LIM_REG_CLA
    in one reasonably fast instruction.  */
 #define MOVE_MAX 65536
 
-/* MOVE_RATIO is the number of move instructions that is better than a
-   block move.  */
+/* If a memory-to-memory move would take MOVE_RATIO or more simple
+   move-instruction pairs, we will do a movstr or libcall instead.  */
 #define MOVE_RATIO 4
 
 /* Define this if zero-extension is slow (more than one real instruction).  */

gcc/config/alpha/alpha.h

@@ -1586,9 +1586,11 @@ do {									\
 
 #define MOVE_MAX 8
 
-/* Controls how many units are moved by expr.c before resorting to movstr.
-   Without byte/word accesses, we want no more than one; with, several single
-   byte accesses are better.   */
+/* If a memory-to-memory move would take MOVE_RATIO or more simple
+   move-instruction pairs, we will do a movstr or libcall instead.
+
+   Without byte/word accesses, we want no more than four instructions;
+   with, several single byte accesses are better.   */
 
 #define MOVE_RATIO  (TARGET_BWX ? 7 : 2)
 

gcc/config/clipper/clipper.h

@@ -815,8 +815,10 @@ do									      \
    in one reasonably fast instruction.  */
 #define MOVE_MAX 4
 
-/* MOVE_RATIO is the number of move instructions that is better than a
-   block move.  Make this large on clipper, since the block move is very
+/* If a memory-to-memory move would take MOVE_RATIO or more simple
+   move-instruction pairs, we will do a movstr or libcall instead.
+
+   Make this large on clipper, since the block move is very
    inefficient with small blocks, and the hard register needs of the
    block move require much reload work. */
 

gcc/config/i386/i386.h

@@ -1890,10 +1890,10 @@ while (0)
    in one reasonably fast instruction.  */
 #define MOVE_MAX 4
 
-/* The number of scalar move insns which should be generated instead
-   of a string move insn or a library call.  Increasing the value
-   will always make code faster, but eventually incurs high cost in
-   increased code size.
+/* If a memory-to-memory move would take MOVE_RATIO or more simple
+   move-instruction pairs, we will do a movstr or libcall instead.
+   Increasing the value will always make code faster, but eventually
+   incurs high cost in increased code size.
 
    If you don't define this, a reasonable default is used.
 

gcc/expr.c

@@ -203,8 +203,8 @@ static rtx do_store_flag	PROTO((tree, rtx, enum machine_mode, int));
 static char direct_load[NUM_MACHINE_MODES];
 static char direct_store[NUM_MACHINE_MODES];
 
-/* MOVE_RATIO is the number of move instructions that is better than
-   a block move.  */
+/* If a memory-to-memory move would take MOVE_RATIO or more simple
+   move-instruction sequences, we will do a movstr or libcall instead.  */
 
 #ifndef MOVE_RATIO
 #if defined (HAVE_movstrqi) || defined (HAVE_movstrhi) || defined (HAVE_movstrsi) || defined (HAVE_movstrdi) || defined (HAVE_movstrti)