This is version 8 of my patch to add -mcpu=future.

I originally made a more complicated patch (V5) on September 22nd, 2025
that tried to do infrastructure cleanup as well as adding -mcpu=future.
This patch is a more limited patch in that it just adds the
-mcpu=future patch, and it does not do the other infrastructure work.

I submitted version 6 of the patch on November 6th.

However, in that patch, I forgot to add code to set the .machine
directive to "future" if the user did -mcpu=future and I submitted
version 7 on November 7th.

This is version 8 of the -mcpu=future patch.  It goes back to the old
method of adding -mcpu=<xxx> options by adding a new ISA bit for that
processor.

If the user uses -mcpu=future, -mfuture is passed to the assembler.

I added support so the configuration option --with-cpu=future is used,
it will set the default cpu type.

Can I check this patch into the GCC trunk?  I have built bootstrap
builds on both a little endian Power10 system and a big endian Power9
system and there were no regressions.  On the little endian Power10
system, I built the last run using the --with-cpu=future configuration
option.

2025-11-14  Michael Meissner  <[email protected]>

gcc/

        * config.gcc (powerpc*-*-*): Add support for -mcpu=future.
        * config/rs6000/aix71.h (ASM_CPU_SPEC): Add support for -mcpu=future.
        * config/rs6000/aix72.h (ASM_CPU_SPEC): Likewise.
        * config/rs6000/aix73.h (ASM_CPU_SPEC): Likewise.
        * config/rs6000/rs6000-c.cc (rs6000_target_modify_macros): Define
        _ARCH_FUTURE if -mcpu=future.
        * config/rs6000/rs6000-cpus.def (FUTURE_MASKS_SERVER): New macros.
        (POWERPC_MASKS): Add OPTION_MASK_FUTURE.
        * config/rs6000/rs6000-tables.opt: Regenerate.
        (future processor): Add -mcpu=future.
        * config/rs6000/rs6000-opts.h (PROCESSOR_FUTURE): Define as power11.
        * config/rs6000/rs6000.h (ASM_CPU_SPEC): Add support for -mcpu=future.
        * config/rs6000/rs6000.opt (-mfuture): New option.
        * doc/invoke.texi (IBM RS/6000 and PowerPC Options): Document
        -mcpu=future.

gcc/testsuite/

        * gcc.target/powerpc/future-1.c: New test.
        * gcc.target/powerpc/future-2.c: Likewise.
---
 gcc/config.gcc                              |  4 ++--
 gcc/config/rs6000/aix71.h                   |  1 +
 gcc/config/rs6000/aix72.h                   |  1 +
 gcc/config/rs6000/aix73.h                   |  1 +
 gcc/config/rs6000/rs6000-c.cc               |  2 ++
 gcc/config/rs6000/rs6000-cpus.def           |  6 ++++++
 gcc/config/rs6000/rs6000-opts.h             |  2 ++
 gcc/config/rs6000/rs6000-tables.opt         |  3 +++
 gcc/config/rs6000/rs6000.cc                 |  3 +++
 gcc/config/rs6000/rs6000.h                  |  1 +
 gcc/config/rs6000/rs6000.opt                |  5 +++++
 gcc/doc/invoke.texi                         |  7 +++++-
 gcc/testsuite/gcc.target/powerpc/future-1.c | 13 +++++++++++
 gcc/testsuite/gcc.target/powerpc/future-2.c | 24 +++++++++++++++++++++
 14 files changed, 70 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/powerpc/future-1.c
 create mode 100644 gcc/testsuite/gcc.target/powerpc/future-2.c

diff --git a/gcc/config.gcc b/gcc/config.gcc
index d2770ea556b..07d0409b509 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -542,7 +542,7 @@ powerpc*-*-*)
        extra_headers="${extra_headers} ppu_intrinsics.h spu2vmx.h vec_types.h 
si2vmx.h"
        extra_headers="${extra_headers} amo.h"
        case x$with_cpu in
-           
xpowerpc64|xdefault64|x6[23]0|x970|xG5|xpower[3456789]|xpower1[01]|xpower6x|xrs64a|xcell|xa2|xe500mc64|xe5500|xe6500)
+           
xpowerpc64|xdefault64|x6[23]0|x970|xG5|xpower[3456789]|xpower1[01]|xpower6x|xrs64a|xcell|xa2|xe500mc64|xe5500|xe6500|xfuture)
                cpu_is_64bit=yes
                ;;
        esac
@@ -5752,7 +5752,7 @@ case "${target}" in
                                tm_defines="${tm_defines} CONFIG_PPC405CR"
                                eval "with_$which=405"
                                ;;
-                       "" | common | native \
+                       "" | common | native | future \
                        | power[3456789] | power1[01] | power5+ | power6x \
                        | powerpc | powerpc64 | powerpc64le \
                        | rs64 \
diff --git a/gcc/config/rs6000/aix71.h b/gcc/config/rs6000/aix71.h
index 2b21dd7cd1e..77651f5ea30 100644
--- a/gcc/config/rs6000/aix71.h
+++ b/gcc/config/rs6000/aix71.h
@@ -79,6 +79,7 @@ do {                                                          
        \
 #undef ASM_CPU_SPEC
 #define ASM_CPU_SPEC \
 "%{mcpu=native: %(asm_cpu_native); \
+  mcpu=future: -mfuture; \
   mcpu=power11: -mpwr11; \
   mcpu=power10: -mpwr10; \
   mcpu=power9: -mpwr9; \
diff --git a/gcc/config/rs6000/aix72.h b/gcc/config/rs6000/aix72.h
index 53c0bde5ad4..652f60c7f49 100644
--- a/gcc/config/rs6000/aix72.h
+++ b/gcc/config/rs6000/aix72.h
@@ -79,6 +79,7 @@ do {                                                          
        \
 #undef ASM_CPU_SPEC
 #define ASM_CPU_SPEC \
 "%{mcpu=native: %(asm_cpu_native); \
+  mcpu=future: -mfuture; \
   mcpu=power11: -mpwr11; \
   mcpu=power10: -mpwr10; \
   mcpu=power9: -mpwr9; \
diff --git a/gcc/config/rs6000/aix73.h b/gcc/config/rs6000/aix73.h
index c7639368a26..3c66ac1d917 100644
--- a/gcc/config/rs6000/aix73.h
+++ b/gcc/config/rs6000/aix73.h
@@ -79,6 +79,7 @@ do {                                                          
        \
 #undef ASM_CPU_SPEC
 #define ASM_CPU_SPEC \
 "%{mcpu=native: %(asm_cpu_native); \
+  mcpu=future: -mfuture; \
   mcpu=power11: -mpwr11; \
   mcpu=power10: -mpwr10; \
   mcpu=power9: -mpwr9; \
diff --git a/gcc/config/rs6000/rs6000-c.cc b/gcc/config/rs6000/rs6000-c.cc
index d3b0a566821..6757a2477ad 100644
--- a/gcc/config/rs6000/rs6000-c.cc
+++ b/gcc/config/rs6000/rs6000-c.cc
@@ -437,6 +437,8 @@ rs6000_target_modify_macros (bool define_p, HOST_WIDE_INT 
flags)
     rs6000_define_or_undefine_macro (define_p, "_ARCH_PWR10");
   if ((flags & OPTION_MASK_POWER11) != 0)
     rs6000_define_or_undefine_macro (define_p, "_ARCH_PWR11");
+  if ((flags & OPTION_MASK_FUTURE) != 0)
+    rs6000_define_or_undefine_macro (define_p, "_ARCH_FUTURE");
   if ((flags & OPTION_MASK_SOFT_FLOAT) != 0)
     rs6000_define_or_undefine_macro (define_p, "_SOFT_FLOAT");
   if ((flags & OPTION_MASK_RECIP_PRECISION) != 0)
diff --git a/gcc/config/rs6000/rs6000-cpus.def 
b/gcc/config/rs6000/rs6000-cpus.def
index 4a1037616d7..18547d82811 100644
--- a/gcc/config/rs6000/rs6000-cpus.def
+++ b/gcc/config/rs6000/rs6000-cpus.def
@@ -83,6 +83,10 @@
 #define POWER11_MASKS_SERVER (ISA_3_1_MASKS_SERVER                     \
                              | OPTION_MASK_POWER11)
 
+/* -mcpu=future flags.  */
+#define FUTURE_MASKS_SERVER    (POWER11_MASKS_SERVER                   \
+                                | OPTION_MASK_FUTURE)
+
 /* Flags that need to be turned off if -mno-vsx.  */
 #define OTHER_VSX_VECTOR_MASKS (OPTION_MASK_EFFICIENT_UNALIGNED_VSX    \
                                 | OPTION_MASK_FLOAT128_KEYWORD         \
@@ -119,6 +123,7 @@
                                 | OPTION_MASK_FLOAT128_HW              \
                                 | OPTION_MASK_FLOAT128_KEYWORD         \
                                 | OPTION_MASK_FPRND                    \
+                                | OPTION_MASK_FUTURE                   \
                                 | OPTION_MASK_POWER10                  \
                                 | OPTION_MASK_POWER11                  \
                                 | OPTION_MASK_P10_FUSION               \
@@ -255,3 +260,4 @@ RS6000_CPU ("powerpc64", PROCESSOR_POWERPC64, 
OPTION_MASK_PPC_GFXOPT
 RS6000_CPU ("powerpc64le", PROCESSOR_POWER8, MASK_POWERPC64
            | ISA_2_7_MASKS_SERVER | OPTION_MASK_HTM)
 RS6000_CPU ("rs64", PROCESSOR_RS64A, OPTION_MASK_PPC_GFXOPT | MASK_POWERPC64)
+RS6000_CPU ("future", PROCESSOR_FUTURE, MASK_POWERPC64 | FUTURE_MASKS_SERVER)
diff --git a/gcc/config/rs6000/rs6000-opts.h b/gcc/config/rs6000/rs6000-opts.h
index c31d2975f04..e13ba2ba527 100644
--- a/gcc/config/rs6000/rs6000-opts.h
+++ b/gcc/config/rs6000/rs6000-opts.h
@@ -71,6 +71,8 @@ enum processor_type
    PROCESSOR_TITAN
 };
 
+/* For now, just use power11 as the base processor for -mcpu=future.  */
+#define PROCESSOR_FUTURE       PROCESSOR_POWER11
 
 /* Types of costly dependences.  */
 enum rs6000_dependence_cost
diff --git a/gcc/config/rs6000/rs6000-tables.opt 
b/gcc/config/rs6000/rs6000-tables.opt
index f5bbed5ea74..9e68c5a66e1 100644
--- a/gcc/config/rs6000/rs6000-tables.opt
+++ b/gcc/config/rs6000/rs6000-tables.opt
@@ -200,3 +200,6 @@ Enum(rs6000_cpu_opt_value) String(powerpc64le) Value(56)
 EnumValue
 Enum(rs6000_cpu_opt_value) String(rs64) Value(57)
 
+EnumValue
+Enum(rs6000_cpu_opt_value) String(future) Value(58)
+
diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 1d5cd25c0f0..61623df146e 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -5913,6 +5913,8 @@ rs6000_machine_from_flags (void)
   flags &= ~(OPTION_MASK_PPC_GFXOPT | OPTION_MASK_PPC_GPOPT | OPTION_MASK_ISEL
             | OPTION_MASK_ALTIVEC);
 
+  if ((flags & (FUTURE_MASKS_SERVER & ~POWER11_MASKS_SERVER)) != 0)
+    return "future";
   if ((flags & (POWER11_MASKS_SERVER & ~ISA_3_1_MASKS_SERVER)) != 0)
     return "power11";
   if ((flags & (ISA_3_1_MASKS_SERVER & ~ISA_3_0_MASKS_SERVER)) != 0)
@@ -24463,6 +24465,7 @@ static struct rs6000_opt_mask const rs6000_opt_masks[] =
   { "float128",                        OPTION_MASK_FLOAT128_KEYWORD,   false, 
true  },
   { "float128-hardware",       OPTION_MASK_FLOAT128_HW,        false, true  },
   { "fprnd",                   OPTION_MASK_FPRND,              false, true  },
+  { "future",                  OPTION_MASK_FUTURE,             false, false },
   { "power10",                 OPTION_MASK_POWER10,            false, true  },
   { "power11",                 OPTION_MASK_POWER11,            false, false },
   { "hard-dfp",                        OPTION_MASK_DFP,                false, 
true  },
diff --git a/gcc/config/rs6000/rs6000.h b/gcc/config/rs6000/rs6000.h
index db6112a09e1..76c6cd1ab8e 100644
--- a/gcc/config/rs6000/rs6000.h
+++ b/gcc/config/rs6000/rs6000.h
@@ -101,6 +101,7 @@
    you make changes here, make them also there.  */
 #define ASM_CPU_SPEC \
 "%{mcpu=native: %(asm_cpu_native); \
+  mcpu=future: -mfuture; \
   mcpu=power11: -mpower11; \
   mcpu=power10: -mpower10; \
   mcpu=power9: -mpower9; \
diff --git a/gcc/config/rs6000/rs6000.opt b/gcc/config/rs6000/rs6000.opt
index 88cf16ca581..7c4f0375424 100644
--- a/gcc/config/rs6000/rs6000.opt
+++ b/gcc/config/rs6000/rs6000.opt
@@ -634,6 +634,11 @@ mieee128-constant
 Target Var(TARGET_IEEE128_CONSTANT) Init(1) Save
 Generate (do not generate) code that uses the LXVKQ instruction.
 
+;; Potential future machine
+mfuture
+Target Undocumented Mask(FUTURE) Var(rs6000_isa_flags) Warn(Do not use 
%<-mfuture>, use %<-mcpu=future>)
+Generate (do not generate) potential future instructions.
+
 ; Documented parameters
 
 -param=rs6000-vect-unroll-limit=
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 27a9e2e5e93..42bd76817b8 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -32326,7 +32326,7 @@ Supported values for @var{cpu_type} are @samp{401}, 
@samp{403},
 @samp{titan}, @samp{power3}, @samp{power4}, @samp{power5}, @samp{power5+},
 @samp{power6}, @samp{power6x}, @samp{power7}, @samp{power8},
 @samp{power9}, @samp{power10}, @samp{power11}, @samp{powerpc}, 
@samp{powerpc64},
-@samp{powerpc64le}, @samp{rs64}, and @samp{native}.
+@samp{powerpc64le}, @samp{rs64}, @samp{future}, and @samp{native}.
 
 @option{-mcpu=powerpc}, @option{-mcpu=powerpc64}, and
 @option{-mcpu=powerpc64le} specify pure 32-bit PowerPC (either
@@ -32334,6 +32334,11 @@ endian), 64-bit big endian PowerPC and 64-bit little 
endian PowerPC
 architecture machine types, with an appropriate, generic processor
 model assumed for scheduling purposes.
 
+Specifying @samp{future} as cpu type adds support for new instructions
+that may be added to future PowerPC processors.  This support is meant
+to try out possible new PowerPC instructions, and these instruction
+may or may not be used in new official PowerPC processors.
+
 Specifying @samp{native} as cpu type detects and selects the
 architecture option that corresponds to the host processor of the
 system performing the compilation.
diff --git a/gcc/testsuite/gcc.target/powerpc/future-1.c 
b/gcc/testsuite/gcc.target/powerpc/future-1.c
new file mode 100644
index 00000000000..7bd8e5ddbd0
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/future-1.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+/* { dg-options "-mdejagnu-cpu=future -O2" } */
+
+/* Basic check to see if the compiler supports -mcpu=future and if it defines
+   _ARCH_FUTURE.  */
+
+#ifndef _ARCH_FUTURE
+#error "-mcpu=future is not supported"
+#endif
+
+void foo (void)
+{
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/future-2.c 
b/gcc/testsuite/gcc.target/powerpc/future-2.c
new file mode 100644
index 00000000000..5552cefa3c2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/future-2.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+/* Check if we can set the future target via a target attribute.  */
+
+__attribute__((__target__("cpu=power9")))
+void foo_p9 (void)
+{
+}
+
+__attribute__((__target__("cpu=power10")))
+void foo_p10 (void)
+{
+}
+
+__attribute__((__target__("cpu=power11")))
+void foo_p11 (void)
+{
+}
+
+__attribute__((__target__("cpu=future")))
+void foo_future (void)
+{
+}
-- 
2.51.1


-- 
Michael Meissner, IBM
PO Box 98, Ayer, Massachusetts, USA, 01432
email: [email protected]

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