[19/28] tcg: Make use of bswap flags in tcg_gen_qemu_st_*

Commit Message

Richard Henderson June 14, 2021, 8:37 a.m. UTC

By removing TCG_BSWAP_IZ we indicate that the input is
not zero-extended, and thus can remove an explicit extend.
By removing TCG_BSWAP_OZ, we allow the implementation to
leave high bits set, which will be ignored by the store.

Signed-off-by: Richard Henderson <[e-mail]>
---
 tcg/tcg-op.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

Comments

Peter Maydell June 21, 2021, 3:05 p.m. UTC | #1

On Mon, 14 Jun 2021 at 09:51, Richard Henderson
<[e-mail]> wrote:
>
> By removing TCG_BSWAP_IZ we indicate that the input is
> not zero-extended, and thus can remove an explicit extend.
> By removing TCG_BSWAP_OZ, we allow the implementation to
> leave high bits set, which will be ignored by the store.
>
> Signed-off-by: Richard Henderson <[e-mail]>

Reviewed-by: Peter Maydell <[e-mail]>

thanks
-- PMM

Patch

diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index 702da7afb7..5dbcd1b0cf 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -2915,8 +2915,7 @@  void tcg_gen_qemu_st_i32(TCGv_i32 val, TCGv addr, TCGArg idx, MemOp memop)
         swap = tcg_temp_new_i32();
         switch (memop & MO_SIZE) {
         case MO_16:
-            tcg_gen_ext16u_i32(swap, val);
-            tcg_gen_bswap16_i32(swap, swap, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
+            tcg_gen_bswap16_i32(swap, val, 0);
             break;
         case MO_32:
             tcg_gen_bswap32_i32(swap, val);
@@ -3013,12 +3012,10 @@  void tcg_gen_qemu_st_i64(TCGv_i64 val, TCGv addr, TCGArg idx, MemOp memop)
         swap = tcg_temp_new_i64();
         switch (memop & MO_SIZE) {
         case MO_16:
-            tcg_gen_ext16u_i64(swap, val);
-            tcg_gen_bswap16_i64(swap, swap, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
+            tcg_gen_bswap16_i64(swap, val, 0);
             break;
         case MO_32:
-            tcg_gen_ext32u_i64(swap, val);
-            tcg_gen_bswap32_i64(swap, swap, TCG_BSWAP_IZ | TCG_BSWAP_OZ);
+            tcg_gen_bswap32_i64(swap, val, 0);
             break;
         case MO_64:
             tcg_gen_bswap64_i64(swap, val);