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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fbe1baebe9d928f3b61e31f18c68150629411b68..8586b042527aefacba3f92642a9d19cb7c5c9dac 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+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.

diff --git a/gcc/config/1750a/1750a.h b/gcc/config/1750a/1750a.h
index e49f6943e5d7ed414f736f2cc4a2877d07453cda..0a3aa8e3c98701f34e68e62efa5416f90f760a43 100644 (file)
--- a/gcc/config/1750a/1750a.h
+++ b/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).  */

diff --git a/gcc/config/alpha/alpha.h b/gcc/config/alpha/alpha.h
index 9aacab5d83310f71fee102f943234cc5dab13298..2021e677895282a68f234789a28d44d9dd416829 100644 (file)
--- a/gcc/config/alpha/alpha.h
+++ b/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)
 

diff --git a/gcc/config/clipper/clipper.h b/gcc/config/clipper/clipper.h
index 407caa2345fc2232964dac14218bd87a82b2a22c..8ce8c473f59368ca58fe54ee79c29db3fa12205b 100644 (file)
--- a/gcc/config/clipper/clipper.h
+++ b/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. */
 

diff --git a/gcc/config/i386/i386.h b/gcc/config/i386/i386.h
index 2042a6b15650ca6f2b5b2817ee37e044a62f6418..2cd77544df31d049a3b779027bd2f48926d34eff 100644 (file)
--- a/gcc/config/i386/i386.h
+++ b/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.
 

diff --git a/gcc/expr.c b/gcc/expr.c
index 03901266ba05c77bbc924cedc14fe01643115273..dbf19ff102d158f22ffc9f4acc0cc03890b82854 100644 (file)
--- a/gcc/expr.c
+++ b/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)