tcg: Optimize spills of constants

While we can store constants via constrants on INDEX_op_st_i32 et al,
we weren't able to spill constants to backing store.

Add a new backend interface, tcg_out_sti, which may store the constant
(and is allowed to fail).  Rearrange the temp_* helpers so that we only
attempt to directly store a constant when the temp is becoming dead/free.

Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 10 insertions, 0 deletions

diff --git a/tcg/sparc/tcg-target.inc.c b/tcg/sparc/tcg-target.inc.c
index 9938a50..8e98172 100644
--- a/tcg/sparc/tcg-target.inc.c
+++ b/tcg/sparc/tcg-target.inc.c
@@ -504,6 +504,16 @@ static inline void tcg_out_st(TCGContext *s, TCGType type, TCGReg arg,
     tcg_out_ldst(s, arg, arg1, arg2, (type == TCG_TYPE_I32 ? STW : STX));
 }
 
+static inline bool tcg_out_sti(TCGContext *s, TCGType type, TCGArg val,
+                               TCGReg base, intptr_t ofs)
+{
+    if (val == 0) {
+        tcg_out_st(s, type, TCG_REG_G0, base, ofs);
+        return true;
+    }
+    return false;
+}
+
 static void tcg_out_ld_ptr(TCGContext *s, TCGReg ret, uintptr_t arg)
 {
     tcg_out_movi(s, TCG_TYPE_PTR, ret, arg & ~0x3ff);