[gcc r12-7498] rs6000: Improve .machine

[gcc r12-7498] rs6000: Improve .machine

[Segher Boessenkool]

https://gcc.gnu.org/g:77eccbf39ed55297802bb66dff5f62507a7239e3

commit r12-7498-g77eccbf39ed55297802bb66dff5f62507a7239e3
Author: Segher Boessenkool <segher@kernel.crashing.org>
Date:   Tue Mar 1 17:04:29 2022 +0000

    rs6000: Improve .machine
    
    This adds more correct .machine for most older CPUs.  It should be
    conservative in the sense that everything we handled before we handle at
    least as well now.  This does not yet revamp the server CPU handling, it
    is too risky at this point in time.
    
    Tested on powerpc64-linux {-m32,-m64}.  Also manually tested with all
    -mcpu=, and the output of that passed through the GNU assembler.
    
    2022-03-04  Segher Boessenkool  <segher@kernel.crashing.org>
    
            * config/rs6000/rs6000.cc (rs6000_machine_from_flags): Restructure a
            bit.  Handle most older CPUs.

Diff:
---
 gcc/config/rs6000/rs6000.cc | 81 ++++++++++++++++++++++++++++++---------------
 1 file changed, 54 insertions(+), 27 deletions(-)

diff --git a/gcc/config/rs6000/rs6000.cc b/gcc/config/rs6000/rs6000.cc
index 2388d44c8cc..7afbc295e03 100644
--- a/gcc/config/rs6000/rs6000.cc
+++ b/gcc/config/rs6000/rs6000.cc
@@ -5764,33 +5764,60 @@ const char *rs6000_machine;
 const char *
 rs6000_machine_from_flags (void)
 {
-  /* For some CPUs, the machine cannot be determined by ISA flags.  We have to
-     check them first.  */
-  switch (rs6000_cpu)
-    {
-    case PROCESSOR_PPC8540:
-    case PROCESSOR_PPC8548:
-      return "e500";
-
-    case PROCESSOR_PPCE300C2:
-    case PROCESSOR_PPCE300C3:
-      return "e300";
-
-    case PROCESSOR_PPCE500MC:
-      return "e500mc";
-
-    case PROCESSOR_PPCE500MC64:
-      return "e500mc64";
-
-    case PROCESSOR_PPCE5500:
-      return "e5500";
-
-    case PROCESSOR_PPCE6500:
-      return "e6500";
-
-    default:
-      break;
-    }
+  /* e300 and e500 */
+  if (rs6000_cpu == PROCESSOR_PPCE300C2 || rs6000_cpu == PROCESSOR_PPCE300C3)
+    return "e300";
+  if (rs6000_cpu == PROCESSOR_PPC8540 || rs6000_cpu == PROCESSOR_PPC8548)
+    return "e500";
+  if (rs6000_cpu == PROCESSOR_PPCE500MC)
+    return "e500mc";
+  if (rs6000_cpu == PROCESSOR_PPCE500MC64)
+    return "e500mc64";
+  if (rs6000_cpu == PROCESSOR_PPCE5500)
+    return "e5500";
+  if (rs6000_cpu == PROCESSOR_PPCE6500)
+    return "e6500";
+
+  /* 400 series */
+  if (rs6000_cpu == PROCESSOR_PPC403)
+    return "\"403\"";
+  if (rs6000_cpu == PROCESSOR_PPC405)
+    return "\"405\"";
+  if (rs6000_cpu == PROCESSOR_PPC440)
+    return "\"440\"";
+  if (rs6000_cpu == PROCESSOR_PPC476)
+    return "\"476\"";
+
+  /* A2 */
+  if (rs6000_cpu == PROCESSOR_PPCA2)
+    return "a2";
+
+  /* Cell BE */
+  if (rs6000_cpu == PROCESSOR_CELL)
+    return "cell";
+
+  /* Titan */
+  if (rs6000_cpu == PROCESSOR_TITAN)
+    return "titan";
+
+  /* 500 series and 800 series */
+  if (rs6000_cpu == PROCESSOR_MPCCORE)
+    return "\"821\"";
+
+  /* 600 series and 700 series, "classic" */
+  if (rs6000_cpu == PROCESSOR_PPC601 || rs6000_cpu == PROCESSOR_PPC603
+      || rs6000_cpu == PROCESSOR_PPC604 || rs6000_cpu == PROCESSOR_PPC604e
+      || rs6000_cpu == PROCESSOR_PPC750 || rs6000_cpu == PROCESSOR_POWERPC)
+    return "ppc";
+
+  /* Classic with AltiVec, "G4" */
+  if (rs6000_cpu == PROCESSOR_PPC7400 || rs6000_cpu == PROCESSOR_PPC7450)
+    return "\"7450\"";
+
+  /* The older 64-bit CPUs */
+  if (rs6000_cpu == PROCESSOR_PPC620 || rs6000_cpu == PROCESSOR_PPC630
+      || rs6000_cpu == PROCESSOR_RS64A || rs6000_cpu == PROCESSOR_POWERPC64)
+    return "ppc64";
 
   HOST_WIDE_INT flags = rs6000_isa_flags;