[v4,27/27] tcg/s390x: Avoid the constant pool in tcg_out_movi

Commit Message

Richard Henderson Dec. 9, 2022, 2:05 a.m. UTC

Load constants in no more than two insns, which turns
out to be faster than using the constant pool.

Suggested-by: Ilya Leoshkevich <[e-mail]>
Signed-off-by: Richard Henderson <[e-mail]>
---
 tcg/s390x/tcg-target.c.inc | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

Comments

Ilya Leoshkevich Dec. 13, 2022, 4:31 p.m. UTC | #1

On Thu, Dec 08, 2022 at 08:05:30PM -0600, Richard Henderson wrote:
> Load constants in no more than two insns, which turns
> out to be faster than using the constant pool.
> 
> Suggested-by: Ilya Leoshkevich <[e-mail]>
> Signed-off-by: Richard Henderson <[e-mail]>
> ---
>  tcg/s390x/tcg-target.c.inc | 23 +++++++++++++++++------
>  1 file changed, 17 insertions(+), 6 deletions(-)

Thanks!

Reviewed-by: Ilya Leoshkevich <[e-mail]>

Patch

diff --git a/tcg/s390x/tcg-target.c.inc b/tcg/s390x/tcg-target.c.inc
index b72c43e4aa..2b38fd991d 100644
--- a/tcg/s390x/tcg-target.c.inc
+++ b/tcg/s390x/tcg-target.c.inc
@@ -877,6 +877,9 @@  static bool tcg_out_mov(TCGContext *s, TCGType type, TCGReg dst, TCGReg src)
 static const S390Opcode li_insns[4] = {
     RI_LLILL, RI_LLILH, RI_LLIHL, RI_LLIHH
 };
+static const S390Opcode oi_insns[4] = {
+    RI_OILL, RI_OILH, RI_OIHL, RI_OIHH
+};
 static const S390Opcode lif_insns[2] = {
     RIL_LLILF, RIL_LLIHF,
 };
@@ -928,9 +931,20 @@  static void tcg_out_movi(TCGContext *s, TCGType type,
         return;
     }
 
-    /* Otherwise, stuff it in the constant pool.  */
-    tcg_out_insn(s, RIL, LGRL, ret, 0);
-    new_pool_label(s, sval, R_390_PC32DBL, s->code_ptr - 2, 2);
+    /* Otherwise, load it by parts. */
+    i = is_const_p16((uint32_t)uval);
+    if (i >= 0) {
+        tcg_out_insn_RI(s, li_insns[i], ret, uval >> (i * 16));
+    } else {
+        tcg_out_insn(s, RIL, LLILF, ret, uval);
+    }
+    uval >>= 32;
+    i = is_const_p16(uval);
+    if (i >= 0) {
+        tcg_out_insn_RI(s, oi_insns[i + 2], ret, uval >> (i * 16));
+    } else {
+        tcg_out_insn(s, RIL, OIHF, ret, uval);
+    }
 }
 
 /* Emit a load/store type instruction.  Inputs are:
@@ -1160,9 +1174,6 @@  static void tgen_andi(TCGContext *s, TCGType type, TCGReg dest, uint64_t val)
 
 static void tgen_ori(TCGContext *s, TCGReg dest, uint64_t val)
 {
-    static const S390Opcode oi_insns[4] = {
-        RI_OILL, RI_OILH, RI_OIHL, RI_OIHH
-    };
     static const S390Opcode oif_insns[2] = {
         RIL_OILF, RIL_OIHF
     };