[gcc(refs/users/meissner/heads/work158-future)] Make -mtune=future be the same as -mtune=power10.

[gcc(refs/users/meissner/heads/work158-future)] Make -mtune=future be the same as -mtune=power10.

[Michael Meissner]

https://gcc.gnu.org/g:cf7d0b0193aedc04407c9bd1df879b050daf56c8

commit cf7d0b0193aedc04407c9bd1df879b050daf56c8
Author: Michael Meissner <meissner@linux.ibm.com>
Date:   Fri Feb 9 20:08:23 2024 -0500

    Make -mtune=future be the same as -mtune=power10.
    
    2024-02-09  Michael Meissner  <meissner@linux.ibm.com>
    
    gcc/
    
            * config/rs6000/rs6000.cc (rs6000_option_override_internal): Make
            -mtune=future become -mtune=power10.

Diff:
---
 gcc/config/rs6000/rs6000.cc | 28 ++++++++++++++++++++++++++--
 1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 2064709aa977..5e5e677e1537 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -3756,16 +3756,40 @@ rs6000_option_override_internal (bool global_init_p)
     rs6000_isa_flags &= ~OPTION_MASK_POWERPC64;
 #endif
 
+  /* At the moment, we don't have explicit -mtune=future support.  If the user
+     explicitly uses -mtune=future, give a warning.  If not, use the power10
+     tuning until future tuning is added.  */
   if (rs6000_tune_index >= 0)
-    tune_index = rs6000_tune_index;
+    {
+      enum processor_type cur_proc
+	= processor_target_table[rs6000_tune_index].processor;
+
+      if (cur_proc == PROCESSOR_FUTURE)
+	{
+	  warning (0, "%qs is not currently supported", "-mtune=future");
+	  rs6000_tune_index = rs6000_cpu_name_lookup ("power10");
+	}
+      tune_index = rs6000_tune_index;
+    }
   else if (cpu_index >= 0)
-    rs6000_tune_index = tune_index = cpu_index;
+    {
+      enum processor_type cur_cpu
+	= processor_target_table[cpu_index].processor;
+
+      rs6000_tune_index = tune_index
+	= (cur_cpu == PROCESSOR_FUTURE
+	   ? rs6000_cpu_name_lookup ("power10")
+	   : cpu_index);
+    }
   else
     {
       size_t i;
       enum processor_type tune_proc
 	= (TARGET_POWERPC64 ? PROCESSOR_DEFAULT64 : PROCESSOR_DEFAULT);
 
+      if (tune_proc == PROCESSOR_FUTURE)
+	tune_proc = PROCESSOR_POWER10;
+
       tune_index = -1;
       for (i = 0; i < ARRAY_SIZE (processor_target_table); i++)
 	if (processor_target_table[i].processor == tune_proc)