[PATCH] config/ppc: fix gcc "internal compiler error" message for p10

[David Christensen]

Building DPDK with gcc 11.3.x for the power10 instruction set may
generate the following error:

../drivers/mempool/cnxk/cnxk_mempool_ops.c
during RTL pass: final
../drivers/mempool/cnxk/cnxk_mempool_ops.c:
  In function ‘cnxk_mempool_alloc’:
../drivers/mempool/cnxk/cnxk_mempool_ops.c:124:1:
  internal compiler error: output_operand: invalid expression as operand
  124 | }
      | ^
Please submit a full bug report,
with preprocessed source if appropriate.
...
ninja: build stopped: subcommand failed.

The same issue is not encoutered when building with gcc 11.4 or
later, where the compiler automatically adds the option
"-mno-block-ops-vector-pair" when building for power10 which
is intended as a code optimization and also effectively avoids
the compiler bug displayed.

Modify the meson.build file for ppc and manually set the flag when
building for power10 with gcc less than 11.4.

Bugzilla ID: 1251

Signed-off-by: David Christensen <drc at linux.vnet.ibm.com>
Tested-by: Thinh Tran <thinhtr at linux.vnet.ibm.com>
---
 config/ppc/meson.build | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/config/ppc/meson.build b/config/ppc/meson.build
index 1cba44011f..160b203cb1 100644
--- a/config/ppc/meson.build
+++ b/config/ppc/meson.build
@@ -105,6 +105,14 @@ else
     endif
 endif
 machine_args = ['-mcpu=' + cpu_instruction_set, '-mtune=' + cpu_instruction_set]
+
+# gcc versions < 11.4 may fail to build for power10, see https://bugs.dpdk.org/show_bug.cgi?id=1251.
+# Explicitly specify a default used in gcc 11.4 and later to workaround the issue
+if (cpu_instruction_set == 'power10' and cc.get_id() == 'gcc' and
+        cc.version().version_compare('<=11.4'))
+    machine_args += '-mno-block-ops-vector-pair'
+endif
+
 dpdk_conf.set('RTE_MACHINE', cpu_instruction_set)
 
 
-- 
2.31.1