tcg-mips: Rearrange register allocation

Use FP (also known as S8) as a normal call-saved register.

Include T0 in the allocation order and call-clobbered list
even though it's currently used as a TCG temporary.

Put the argument registers at the end of the allocation order.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>

diff --git a/tcg/mips/tcg-target.c b/tcg/mips/tcg-target.c
index 4c31027..16b8f7f 100644 (file)
--- a/tcg/mips/tcg-target.c
+++ b/tcg/mips/tcg-target.c
@@ -67,13 +67,14 @@ static const char * const tcg_target_reg_names[TCG_TARGET_NB_REGS] = {
     "k1",
     "gp",
     "sp",
-    "fp",
+    "s8",
     "ra",
 };
 #endif
 
 /* check if we really need so many registers :P */
 static const TCGReg tcg_target_reg_alloc_order[] = {
+    /* Call saved registers.  */
     TCG_REG_S0,
     TCG_REG_S1,
     TCG_REG_S2,
@@ -82,6 +83,10 @@ static const TCGReg tcg_target_reg_alloc_order[] = {
     TCG_REG_S5,
     TCG_REG_S6,
     TCG_REG_S7,
+    TCG_REG_S8,
+
+    /* Call clobbered registers.  */
+    TCG_REG_T0,
     TCG_REG_T1,
     TCG_REG_T2,
     TCG_REG_T3,
@@ -91,12 +96,14 @@ static const TCGReg tcg_target_reg_alloc_order[] = {
     TCG_REG_T7,
     TCG_REG_T8,
     TCG_REG_T9,
-    TCG_REG_A0,
-    TCG_REG_A1,
-    TCG_REG_A2,
-    TCG_REG_A3,
+    TCG_REG_V1,
     TCG_REG_V0,
-    TCG_REG_V1
+
+    /* Argument registers, opposite order of allocation.  */
+    TCG_REG_A3,
+    TCG_REG_A2,
+    TCG_REG_A1,
+    TCG_REG_A0,
 };
 
 static const TCGReg tcg_target_call_iarg_regs[4] = {
@@ -1646,7 +1653,7 @@ static int tcg_target_callee_save_regs[] = {
     TCG_REG_S5,
     TCG_REG_S6,
     TCG_REG_S7,
-    TCG_REG_FP,
+    TCG_REG_S8,
     TCG_REG_RA,       /* should be last for ABI compliance */
 };
 
@@ -1778,6 +1785,7 @@ static void tcg_target_init(TCGContext *s)
                    (1 << TCG_REG_A1) |
                    (1 << TCG_REG_A2) |
                    (1 << TCG_REG_A3) |
+                   (1 << TCG_REG_T0) |
                    (1 << TCG_REG_T1) |
                    (1 << TCG_REG_T2) |
                    (1 << TCG_REG_T3) |

diff --git a/tcg/mips/tcg-target.h b/tcg/mips/tcg-target.h
index 7509fa1..c959d1c 100644 (file)
--- a/tcg/mips/tcg-target.h
+++ b/tcg/mips/tcg-target.h
@@ -60,8 +60,11 @@ typedef enum {
     TCG_REG_K1,
     TCG_REG_GP,
     TCG_REG_SP,
-    TCG_REG_FP,
+    TCG_REG_S8,
     TCG_REG_RA,
+
+    TCG_REG_CALL_STACK = TCG_REG_SP,
+    TCG_AREG0 = TCG_REG_S0,
 } TCGReg;
 
 #define TCG_CT_CONST_ZERO 0x100
@@ -69,7 +72,6 @@ typedef enum {
 #define TCG_CT_CONST_S16  0x400
 
 /* used for function call generation */
-#define TCG_REG_CALL_STACK TCG_REG_SP
 #define TCG_TARGET_STACK_ALIGN 8
 #define TCG_TARGET_CALL_STACK_OFFSET 16
 #define TCG_TARGET_CALL_ALIGN_ARGS 1
@@ -127,8 +129,6 @@ extern bool use_mips32r2_instructions;
 #define TCG_TARGET_HAS_ext8u_i32        0 /* andi rt, rs, 0xff   */
 #define TCG_TARGET_HAS_ext16u_i32       0 /* andi rt, rs, 0xffff */
 
-#define TCG_AREG0 TCG_REG_S0
-
 #ifdef __OpenBSD__
 #include <machine/sysarch.h>
 #else