[RFC PATCH 3/4] tcg/ppc: Optimize memory ordering generation with lwsync

[Nicholas Piggin]

lwsync orders more than just LD_LD, importantly it matches x86 and
s390 default memory ordering.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/cpu.h         | 2 ++
 tcg/ppc/tcg-target.c.inc | 2 +-
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index c2b6c987c0..0b0e9761cd 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -28,6 +28,8 @@
 
 #define TCG_GUEST_DEFAULT_MO 0
 
+#define PPC_LWSYNC_MO (TCG_MO_LD_LD | TCG_MO_LD_ST | TCG_MO_ST_ST)
+
 #define TARGET_PAGE_BITS_64K 16
 #define TARGET_PAGE_BITS_16M 24
 
diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index 3ff845d063..b87fc2383e 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -1834,7 +1834,7 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0)
 {
     uint32_t insn = HWSYNC;
     a0 &= TCG_MO_ALL;
-    if (a0 == TCG_MO_LD_LD) {
+    if ((a0 & PPC_LWSYNC_MO) == a0) {
         insn = LWSYNC;
     }
     tcg_out32(s, insn);
-- 
2.35.1