tcg: Introduce tcg_out_movext2

This is common code in most qemu_{ld,st} slow paths, moving two
registers when there may be overlap between sources and destinations.
At present, this is only used by 32-bit hosts for 64-bit data,
but will shortly be used for more than that.

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

1 files changed, 8 insertions, 11 deletions

diff --git a/tcg/i386/tcg-target.c.inc b/tcg/i386/tcg-target.c.inc
index c8e2bf537f..caf91a3151 100644
--- a/tcg/i386/tcg-target.c.inc
+++ b/tcg/i386/tcg-target.c.inc
@@ -1914,7 +1914,6 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
 {
     MemOpIdx oi = l->oi;
     MemOp opc = get_memop(oi);
-    TCGReg data_reg;
     tcg_insn_unit **label_ptr = &l->label_ptr[0];
 
     /* resolve label address */
@@ -1951,18 +1950,16 @@ static bool tcg_out_qemu_ld_slow_path(TCGContext *s, TCGLabelQemuLdst *l)
 
     tcg_out_branch(s, 1, qemu_ld_helpers[opc & (MO_BSWAP | MO_SIZE)]);
 
-    data_reg = l->datalo_reg;
     if (TCG_TARGET_REG_BITS == 32 && (opc & MO_SIZE) == MO_64) {
-        if (data_reg == TCG_REG_EDX) {
-            /* xchg %edx, %eax */
-            tcg_out_opc(s, OPC_XCHG_ax_r32 + TCG_REG_EDX, 0, 0, 0);
-            tcg_out_mov(s, TCG_TYPE_I32, l->datahi_reg, TCG_REG_EAX);
-        } else {
-            tcg_out_mov(s, TCG_TYPE_I32, data_reg, TCG_REG_EAX);
-            tcg_out_mov(s, TCG_TYPE_I32, l->datahi_reg, TCG_REG_EDX);
-        }
+        TCGMovExtend ext[2] = {
+            { .dst = l->datalo_reg, .dst_type = TCG_TYPE_I32,
+              .src = TCG_REG_EAX, .src_type = TCG_TYPE_I32, .src_ext = MO_UL },
+            { .dst = l->datahi_reg, .dst_type = TCG_TYPE_I32,
+              .src = TCG_REG_EDX, .src_type = TCG_TYPE_I32, .src_ext = MO_UL },
+        };
+        tcg_out_movext2(s, &ext[0], &ext[1], -1);
     } else {
-        tcg_out_movext(s, l->type, data_reg,
+        tcg_out_movext(s, l->type, l->datalo_reg,
                        TCG_TYPE_REG, opc & MO_SSIZE, TCG_REG_EAX);
     }