[Qemu-devel] [PATCH 14/35] tcg-s390: Rearrange register allocation order.

[Richard Henderson]

Try to avoid conflicting with the outgoing function call arguments.

Signed-off-by: Richard Henderson <address@hidden>
---
 tcg/s390/tcg-target.c |   23 +++++++++++++----------
 1 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/tcg/s390/tcg-target.c b/tcg/s390/tcg-target.c
index 95ea3c8..3944cb1 100644
--- a/tcg/s390/tcg-target.c
+++ b/tcg/s390/tcg-target.c
@@ -149,22 +149,25 @@ static const char * const 
tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
 };
 #endif
 
+/* Since R6 is a potential argument register, choose it last of the
+   call-saved registers.  Likewise prefer the call-clobbered registers
+   in reverse order to maximize the chance of avoiding the arguments.  */
 static const int tcg_target_reg_alloc_order[] = {
-    TCG_REG_R6,
-    TCG_REG_R7,
-    TCG_REG_R8,
-    TCG_REG_R9,
-    TCG_REG_R10,
-    TCG_REG_R11,
-    TCG_REG_R12,
     TCG_REG_R13,
+    TCG_REG_R12,
+    TCG_REG_R11,
+    TCG_REG_R10,
+    TCG_REG_R9,
+    TCG_REG_R8,
+    TCG_REG_R7,
+    TCG_REG_R6,
     TCG_REG_R14,
     TCG_REG_R0,
     TCG_REG_R1,
-    TCG_REG_R2,
-    TCG_REG_R3,
-    TCG_REG_R4,
     TCG_REG_R5,
+    TCG_REG_R4,
+    TCG_REG_R3,
+    TCG_REG_R2,
 };
 
 static const int tcg_target_call_iarg_regs[] = {
-- 
1.7.0.1