tcg/mips: Aggressively use the constant pool for n64 calls

Repeated calls to a single helper are common -- especially
the ones for softmmu memory access.  Prefer the constant pool
to longer sequences to increase sharing.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

tcg/mips/tcg-target.c.inc

@@ -1101,9 +1101,19 @@ static void tcg_out_movcond(TCGContext *s, TCGCond cond, TCGReg ret,
 
 static void tcg_out_call_int(TCGContext *s, const tcg_insn_unit *arg, bool tail)
 {
-    /* Note that the ABI requires the called function's address to be
-       loaded into T9, even if a direct branch is in range.  */
-    tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_T9, (uintptr_t)arg);
+    /*
+     * Note that __mips_abicalls requires the called function's address
+     * to be loaded into $25 (t9), even if a direct branch is in range.
+     *
+     * For n64, always drop the pointer into the constant pool.
+     * We can re-use helper addresses often and do not want any
+     * of the longer sequences tcg_out_movi may try.
+     */
+    if (sizeof(uintptr_t) == 8) {
+        tcg_out_movi_pool(s, TCG_REG_T9, (uintptr_t)arg, TCG_REG_TB);
+    } else {
+        tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_T9, (uintptr_t)arg);
+    }
 
     /* But do try a direct branch, allowing the cpu better insn prefetch.  */
     if (tail) {