tcg/tci: Reserve r13 for a temporary

We're about to adjust the offset range on host memory ops,
and the format of branches.  Both will require a temporary.

Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/tci/tcg-target.c.inc

@@ -820,6 +820,7 @@ static void tcg_target_init(TCGContext *s)
         MAKE_64BIT_MASK(TCG_REG_R0, 64 / TCG_TARGET_REG_BITS);
 
     s->reserved_regs = 0;
+    tcg_regset_set_reg(s->reserved_regs, TCG_REG_TMP);
     tcg_regset_set_reg(s->reserved_regs, TCG_REG_CALL_STACK);
 
     /* The call arguments come first, followed by the temp storage. */

tcg/tci/tcg-target.h

@@ -156,6 +156,7 @@ typedef enum {
     TCG_REG_R14,
     TCG_REG_R15,
 
+    TCG_REG_TMP = TCG_REG_R13,
     TCG_AREG0 = TCG_REG_R14,
     TCG_REG_CALL_STACK = TCG_REG_R15,
 } TCGReg;