cse.c (count_reg_usage): Correctly handle REG_NONNEG notes.

        * cse.c (count_reg_usage): Correctly handle REG_NONNEG notes.
        (delete_trivially_dead_insns): Renamed from delete_dead_from_cse.
        * toplev.c (rest_of_compilation): Call delete_trivially_dead_insns
        instead of delete_dead_from_cse.  Also call delete_trivially_dead_insns
        between loop optimization passes.
        * rtl.h: Updated appropriately.

From-SVN: r19100

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1c15d1dc3a650a5f264613dde5dda1b41b35ef44..b002afa2453beb5f23206b876658c3037f880db5 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+Sat Apr 11 01:24:28 1998  Jeffrey A Law  (law@cygnus.com)
+
+       * cse.c (count_reg_usage): Correctly handle REG_NONNEG notes.
+       (delete_trivially_dead_insns): Renamed from delete_dead_from_cse.
+       * toplev.c (rest_of_compilation): Call delete_trivially_dead_insns              instead of delete_dead_from_cse.  Also call delete_trivially_dead_insns
+       between loop optimization passes.
+       * rtl.h: Updated appropriately.
+
 Fri Apr 10 22:28:32 1998  Jeffrey A Law  (law@cygnus.com)
 
        Reinstall this patch from Jason.

diff --git a/gcc/cse.c b/gcc/cse.c
index 990ef5f1700ed947783da61f677a3ae58c8832cf..19a02eff778531a5205892691a7de659e6a23a0e 100644 (file)
--- a/gcc/cse.c
+++ b/gcc/cse.c
@@ -8731,7 +8731,7 @@ count_reg_usage (x, counts, dest, incr)
     case EXPR_LIST:
     case INSN_LIST:
       if (REG_NOTE_KIND (x) == REG_EQUAL
-         || GET_CODE (XEXP (x,0)) == USE)
+         || (REG_NOTE_KIND (x) != REG_NONNEG && GET_CODE (XEXP (x,0)) == USE))
        count_reg_usage (XEXP (x, 0), counts, NULL_RTX, incr);
       count_reg_usage (XEXP (x, 1), counts, NULL_RTX, incr);
       return;
@@ -8754,13 +8754,13 @@ count_reg_usage (x, counts, dest, incr)
 /* Scan all the insns and delete any that are dead; i.e., they store a register
    that is never used or they copy a register to itself.
 
-   This is used to remove insns made obviously dead by cse.  It improves the
-   heuristics in loop since it won't try to move dead invariants out of loops
-   or make givs for dead quantities.  The remaining passes of the compilation
-   are also sped up.  */
+   This is used to remove insns made obviously dead by cse, loop or other
+   optimizations.  It improves the heuristics in loop since it won't try to
+   move dead invariants out of loops or make givs for dead quantities.  The
+   remaining passes of the compilation are also sped up.  */
 
 void
-delete_dead_from_cse (insns, nreg)
+delete_trivially_dead_insns (insns, nreg)
      rtx insns;
      int nreg;
 {

diff --git a/gcc/rtl.h b/gcc/rtl.h
index 0d3d5b7201219b6ff41f0536d91996a3e1282ca8..c01770a90f3af24aa256a0e42d72dec95244f242 100644 (file)
--- a/gcc/rtl.h
+++ b/gcc/rtl.h
@@ -1115,7 +1115,7 @@ extern int read_skip_spaces               PROTO ((FILE *));
 /* In cse.c */
 struct cse_basic_block_data;
 extern int rtx_cost                    PROTO ((rtx, enum rtx_code));
-extern void delete_dead_from_cse       PROTO ((rtx, int));
+extern void delete_trivially_dead_insns        PROTO ((rtx, int));
 #ifdef BUFSIZ
 extern int cse_main                    PROTO ((rtx, int, int, FILE *));
 #endif

diff --git a/gcc/toplev.c b/gcc/toplev.c
index 90cc6f46e65d0f08bea6b4c1a1f3ae15b1c467a3..b841b2c18dbd19458caf92cf481646b3f9113993 100644 (file)
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -3211,7 +3211,7 @@ rest_of_compilation (decl)
 
       TIMEVAR (cse_time, tem = cse_main (insns, max_reg_num (),
                                         0, rtl_dump_file));
-      TIMEVAR (cse_time, delete_dead_from_cse (insns, max_reg_num ()));
+      TIMEVAR (cse_time, delete_trivially_dead_insns (insns, max_reg_num ()));
 
       if (tem || optimize > 1)
        TIMEVAR (jump_time, jump_optimize (insns, 0, 0, 0));
@@ -3244,8 +3244,15 @@ rest_of_compilation (decl)
               
               loop_optimize (insns, rtl_dump_file, 0);
               
-              /* The regscan pass may not be necessary, but let's
-                 be safe until we can prove otherwise.  */
+       
+              /* The first call to loop_optimize makes some instructions
+                 trivially dead.  We delete those instructions now in the
+                 hope that doing so will make the heuristics in loop work
+                 better and possibly speed up compilation.  */
+              delete_trivially_dead_insns (insns, max_reg_num ());
+
+              /* The regscan pass is currently necessary as the alias
+                 analysis code depends on this information.  */
               reg_scan (insns, max_reg_num (), 1);
             }
           loop_optimize (insns, rtl_dump_file, flag_unroll_loops);