toplev.c (flag_rerun_loop_opt): New variable.

        * toplev.c (flag_rerun_loop_opt): New variable.
        (f_options): Handle -frerun-loop-opt.
        (rest_of_compilation): If -frerun-loop-opt, then run the loop
        optimizer twice.
        (main): Enable -frerun-loop-opt by default for -O2 or greater.

From-SVN: r16180

gcc/ChangeLog

 Sun Oct 26 09:21:40 1997  Jeffrey A Law  (law@cygnus.com)
 
+	* toplev.c (flag_rerun_loop_opt): New variable.
+	(f_options): Handle -frerun-loop-opt.
+	(rest_of_compilation): If -frerun-loop-opt, then run the loop
+	optimizer twice.
+	(main): Enable -frerun-loop-opt by default for -O2 or greater.
+
 	* loop.c (simplify_giv_expr): Adding two invariants results
 	in an invariant.
 

gcc/invoke.texi

@@ -149,7 +149,7 @@ in the following sections.
 -fkeep-inline-functions  -fno-default-inline
 -fno-defer-pop  -fno-function-cse
 -fno-inline  -fno-peephole  -fomit-frame-pointer -fregmove
--frerun-cse-after-loop  -fschedule-insns
+-frerun-cse-after-loop  -frerun-loop-opt -fschedule-insns
 -fschedule-insns2  -fstrength-reduce  -fthread-jumps
 -funroll-all-loops  -funroll-loops
 -fmove-all-movables  -freduce-all-givs
@@ -245,6 +245,10 @@ in the following sections.
 -msoft-float  -mhard-float
 -mbsd  -mxopen  -mno-symrename
 
+@emph{MN10300 Options}
+-mmult-bug
+-mno-mult-bug
+
 @emph{M32R/D Options}
 -mcode-model=@var{model type}  -msdata=@var{sdata type}
 -G @var{num}
@@ -2165,6 +2169,9 @@ body of the @code{if}.
 Re-run common subexpression elimination after loop optimizations has been
 performed.
 
+@item -frerun-loop-opt
+Run the loop optimizer twice.
+
 @item -fexpensive-optimizations
 Perform a number of minor optimizations that are relatively expensive.
 
@@ -2798,6 +2805,7 @@ that macro, which enables you to change the defaults.
 * Convex Options::
 * AMD29K Options::
 * ARM Options::
+* MN10300 Options::
 * M32R/D Options::
 * M88K Options::
 * RS/6000 and PowerPC Options::
@@ -3437,6 +3445,21 @@ suppresses this pass.  The post-processor is never run when the
 compiler is built for cross-compilation.
 @end table
 
+@node MN10300 Options
+@subsection MN10300 Options
+@cindex MN10300 options
+These @samp{-m} options are defined for Matsushita MN10300 architectures:
+
+@table @code
+@item -mmult-bug
+Generate code to avoid bugs in the multiply instructions for the MN10300
+processors.  This is the default.
+
+@item -mno-mult-bug
+Do not generate code to avoid bugs in the multiply instructions for the
+MN10300 processors.
+@end table
+
 @node M32R/D Options
 @subsection M32R/D Options
 @cindex M32R/D options

gcc/toplev.c

@@ -505,6 +505,10 @@ int flag_syntax_only = 0;
 
 static int flag_rerun_cse_after_loop;
 
+/* Nonzero means to run loop optimizations twice.  */
+
+static int flag_rerun_loop_opt;
+
 /* Nonzero for -finline-functions: ok to inline functions that look like
    good inline candidates.  */
 
@@ -707,6 +711,7 @@ struct { char *string; int *variable; int on_value;} f_options[] =
   {"reg-struct-return", &flag_pcc_struct_return, 0},
   {"delayed-branch", &flag_delayed_branch, 1},
   {"rerun-cse-after-loop", &flag_rerun_cse_after_loop, 1},
+  {"rerun-loop-opt", &flag_rerun_loop_opt, 1},
   {"pretend-float", &flag_pretend_float, 1},
   {"schedule-insns", &flag_schedule_insns, 1},
   {"schedule-insns2", &flag_schedule_insns_after_reload, 1},
@@ -3262,6 +3267,27 @@ rest_of_compilation (decl)
     {
       TIMEVAR (loop_time,
 	       {
+		 int save_flag_unroll_loops;
+		 int save_flag_unroll_all_loops;
+
+		 if (flag_rerun_loop_opt)
+		   {
+		      /* We only want to perform unrolling once.  */
+		      save_flag_unroll_loops = flag_unroll_loops;
+		      save_flag_unroll_all_loops = flag_unroll_all_loops;
+		      flag_unroll_loops = 0;
+		      flag_unroll_all_loops = 0;
+
+		      loop_optimize (insns, loop_dump_file);
+
+		      /* The regscan pass may not be necessary, but let's
+			 be safe until we can prove otherwise.  */
+		      reg_scan (insns, max_reg_num (), 1);
+
+		      /* Restore loop unrolling flags.  */
+		      flag_unroll_loops = save_flag_unroll_loops;
+		      flag_unroll_all_loops = save_flag_unroll_all_loops;
+		   }
 		 loop_optimize (insns, loop_dump_file);
 	       });
     }
@@ -3819,6 +3845,7 @@ main (argc, argv, envp)
       flag_expensive_optimizations = 1;
       flag_strength_reduce = 1;
       flag_rerun_cse_after_loop = 1;
+      flag_rerun_loop_opt = 1;
       flag_caller_saves = 1;
       flag_force_mem = 1;
 #ifdef INSN_SCHEDULING