[PATCH 1/2] tcg: Improve expansion of deposit of constant

[Richard Henderson]

The extract2 expansion is too difficult for the optimizer to
simplify.  If we have an immediate input, use and+or instead,
skipping the and if the field becomes all 1's.

Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
 tcg/tcg-op.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
index 393dbcd01c..2ef4b866e2 100644
--- a/tcg/tcg-op.c
+++ b/tcg/tcg-op.c
@@ -602,6 +602,7 @@ void tcg_gen_deposit_i32(TCGv_i32 ret, TCGv_i32 arg1, 
TCGv_i32 arg2,
 {
     uint32_t mask;
     TCGv_i32 t1;
+    TCGTemp *ts;
 
     tcg_debug_assert(ofs < 32);
     tcg_debug_assert(len > 0);
@@ -617,6 +618,19 @@ void tcg_gen_deposit_i32(TCGv_i32 ret, TCGv_i32 arg1, 
TCGv_i32 arg2,
         return;
     }
 
+    /* Deposit of a constant into a value. */
+    ts = tcgv_i32_temp(arg2);
+    if (ts->kind == TEMP_CONST) {
+        uint32_t mask0 = deposit32(-1, ofs, len, 0);
+        uint32_t maski = deposit32(0, ofs, len, ts->val);
+
+        if (mask0 != ~maski) {
+            tcg_gen_andi_i32(ret, arg1, mask0);
+        }
+        tcg_gen_ori_i32(ret, ret, maski);
+        return;
+    }
+
     t1 = tcg_temp_ebb_new_i32();
 
     if (TCG_TARGET_HAS_extract2_i32) {
@@ -2217,6 +2231,7 @@ void tcg_gen_deposit_i64(TCGv_i64 ret, TCGv_i64 arg1, 
TCGv_i64 arg2,
 {
     uint64_t mask;
     TCGv_i64 t1;
+    TCGTemp *ts;
 
     tcg_debug_assert(ofs < 64);
     tcg_debug_assert(len > 0);
@@ -2232,6 +2247,19 @@ void tcg_gen_deposit_i64(TCGv_i64 ret, TCGv_i64 arg1, 
TCGv_i64 arg2,
         return;
     }
 
+    /* Deposit of a constant into a value. */
+    ts = tcgv_i64_temp(arg2);
+    if (ts->kind == TEMP_CONST) {
+        uint64_t mask0 = deposit64(-1, ofs, len, 0);
+        uint64_t maski = deposit64(0, ofs, len, ts->val);
+
+        if (mask0 != ~maski) {
+            tcg_gen_andi_i64(ret, arg1, mask0);
+        }
+        tcg_gen_ori_i64(ret, ret, maski);
+        return;
+    }
+
     if (TCG_TARGET_REG_BITS == 32) {
         if (ofs >= 32) {
             tcg_gen_deposit_i32(TCGV_HIGH(ret), TCGV_HIGH(arg1),
-- 
2.34.1