tcg: Add INDEX_op_trunc_shr_i32

Let the backend do something special for truncation.
Signed-off-by: NRichard Henderson <rth@twiddle.net>

tcg/README

@@ -314,6 +314,11 @@ This operation would be equivalent to
 
   dest = (t1 & ~0x0f00) | ((t2 << 8) & 0x0f00)
 
+* trunc_shr_i32 t0, t1, pos
+
+For 64-bit hosts only, right shift the 64-bit input T1 by POS and
+truncate to 32-bit output T0.  Depending on the host, this may be
+a simple mov/shift, or may require additional canonicalization.
 
 ********* Conditional moves
 

tcg/aarch64/tcg-target.h

@@ -68,6 +68,7 @@ typedef enum {
 #define TCG_TARGET_HAS_muls2_i32        0
 #define TCG_TARGET_HAS_muluh_i32        0
 #define TCG_TARGET_HAS_mulsh_i32        0
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 
 #define TCG_TARGET_HAS_div_i64          1
 #define TCG_TARGET_HAS_rem_i64          1

tcg/i386/tcg-target.h

@@ -99,6 +99,7 @@ extern bool have_bmi1;
 #define TCG_TARGET_HAS_mulsh_i32        0
 
 #if TCG_TARGET_REG_BITS == 64
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 #define TCG_TARGET_HAS_div2_i64         1
 #define TCG_TARGET_HAS_rot_i64          1
 #define TCG_TARGET_HAS_ext8s_i64        1

tcg/ia64/tcg-target.h

@@ -152,6 +152,7 @@ typedef enum {
 #define TCG_TARGET_HAS_muluh_i64        0
 #define TCG_TARGET_HAS_mulsh_i32        0
 #define TCG_TARGET_HAS_mulsh_i64        0
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 
 #define TCG_TARGET_HAS_new_ldst         1
 

tcg/optimize.c

@@ -228,6 +228,7 @@ static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
     case INDEX_op_shr_i32:
         return (uint32_t)x >> (y & 31);
 
+    case INDEX_op_trunc_shr_i32:
     case INDEX_op_shr_i64:
         return (uint64_t)x >> (y & 63);
 
@@ -830,6 +831,10 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
             }
             break;
 
+        case INDEX_op_trunc_shr_i32:
+            mask = (uint64_t)temps[args[1]].mask >> args[2];
+            break;
+
         CASE_OP_32_64(shl):
             if (temps[args[2]].state == TCG_TEMP_CONST) {
                 tmp = temps[args[2]].val & (TCG_TARGET_REG_BITS - 1);
@@ -1021,6 +1026,17 @@ static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
             }
             goto do_default;
 
+        case INDEX_op_trunc_shr_i32:
+            if (temps[args[1]].state == TCG_TEMP_CONST) {
+                s->gen_opc_buf[op_index] = op_to_movi(op);
+                tmp = do_constant_folding(op, temps[args[1]].val, args[2]);
+                tcg_opt_gen_movi(gen_args, args[0], tmp);
+                gen_args += 2;
+                args += 3;
+                break;
+            }
+            goto do_default;
+
         CASE_OP_32_64(add):
         CASE_OP_32_64(sub):
         CASE_OP_32_64(mul):

tcg/ppc64/tcg-target.h

@@ -96,6 +96,7 @@ typedef enum {
 #define TCG_TARGET_HAS_muls2_i32        0
 #define TCG_TARGET_HAS_muluh_i32        0
 #define TCG_TARGET_HAS_mulsh_i32        0
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 
 #define TCG_TARGET_HAS_div_i64          1
 #define TCG_TARGET_HAS_rem_i64          0

tcg/s390/tcg-target.h

@@ -69,6 +69,7 @@ typedef enum TCGReg {
 #define TCG_TARGET_HAS_muls2_i32        0
 #define TCG_TARGET_HAS_muluh_i32        0
 #define TCG_TARGET_HAS_mulsh_i32        0
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 
 #define TCG_TARGET_HAS_div2_i64         1
 #define TCG_TARGET_HAS_rot_i64          1

tcg/sparc/tcg-target.h

@@ -117,6 +117,7 @@ typedef enum {
 #define TCG_TARGET_HAS_mulsh_i32        0
 
 #if TCG_TARGET_REG_BITS == 64
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 #define TCG_TARGET_HAS_div_i64          1
 #define TCG_TARGET_HAS_rem_i64          0
 #define TCG_TARGET_HAS_rot_i64          0

tcg/tcg-op.h

@@ -1624,9 +1624,20 @@ static inline void tcg_gen_ext32u_i64(TCGv_i64 ret, TCGv_i64 arg)
     tcg_gen_movi_i32(TCGV_HIGH(ret), 0);
 }
 
-static inline void tcg_gen_trunc_i64_i32(TCGv_i32 ret, TCGv_i64 arg)
+static inline void tcg_gen_trunc_shr_i64_i32(TCGv_i32 ret, TCGv_i64 arg,
+                                             unsigned int count)
 {
-    tcg_gen_mov_i32(ret, TCGV_LOW(arg));
+    tcg_debug_assert(count < 64);
+    if (count >= 32) {
+        tcg_gen_shri_i32(ret, TCGV_HIGH(arg), count - 32);
+    } else if (count == 0) {
+        tcg_gen_mov_i32(ret, TCGV_LOW(arg));
+    } else {
+        TCGv_i64 t = tcg_temp_new_i64();
+        tcg_gen_shri_i64(t, arg, count);
+        tcg_gen_mov_i32(ret, TCGV_LOW(t));
+        tcg_temp_free_i64(t);
+    }
 }
 
 static inline void tcg_gen_extu_i32_i64(TCGv_i64 ret, TCGv_i32 arg)
@@ -1727,11 +1738,21 @@ static inline void tcg_gen_ext32u_i64(TCGv_i64 ret, TCGv_i64 arg)
     }
 }
 
-/* Note: we assume the target supports move between 32 and 64 bit
-   registers.  This will probably break MIPS64 targets.  */
-static inline void tcg_gen_trunc_i64_i32(TCGv_i32 ret, TCGv_i64 arg)
+static inline void tcg_gen_trunc_shr_i64_i32(TCGv_i32 ret, TCGv_i64 arg,
+                                             unsigned int count)
 {
-    tcg_gen_mov_i32(ret, MAKE_TCGV_I32(GET_TCGV_I64(arg)));
+    tcg_debug_assert(count < 64);
+    if (TCG_TARGET_HAS_trunc_shr_i32) {
+        tcg_gen_op3i_i32(INDEX_op_trunc_shr_i32, ret,
+                         MAKE_TCGV_I32(GET_TCGV_I64(arg)), count);
+    } else if (count == 0) {
+        tcg_gen_mov_i32(ret, MAKE_TCGV_I32(GET_TCGV_I64(arg)));
+    } else {
+        TCGv_i64 t = tcg_temp_new_i64();
+        tcg_gen_shri_i64(t, arg, count);
+        tcg_gen_mov_i32(ret, MAKE_TCGV_I32(GET_TCGV_I64(t)));
+        tcg_temp_free_i64(t);
+    }
 }
 
 /* Note: we assume the target supports move between 32 and 64 bit
@@ -2275,18 +2296,15 @@ static inline void tcg_gen_concat32_i64(TCGv_i64 dest, TCGv_i64 low,
     tcg_gen_deposit_i64(dest, low, high, 32, 32);
 }
 
+static inline void tcg_gen_trunc_i64_i32(TCGv_i32 ret, TCGv_i64 arg)
+{
+    tcg_gen_trunc_shr_i64_i32(ret, arg, 0);
+}
+
 static inline void tcg_gen_extr_i64_i32(TCGv_i32 lo, TCGv_i32 hi, TCGv_i64 arg)
 {
-#if TCG_TARGET_REG_BITS == 32
-    tcg_gen_mov_i32(lo, TCGV_LOW(arg));
-    tcg_gen_mov_i32(hi, TCGV_HIGH(arg));
-#else
-    TCGv_i64 t0 = tcg_temp_new_i64();
-    tcg_gen_trunc_i64_i32(lo, arg);
-    tcg_gen_shri_i64(t0, arg, 32);
-    tcg_gen_trunc_i64_i32(hi, t0);
-    tcg_temp_free_i64(t0);
-#endif
+    tcg_gen_trunc_shr_i64_i32(lo, arg, 0);
+    tcg_gen_trunc_shr_i64_i32(hi, arg, 32);
 }
 
 static inline void tcg_gen_extr32_i64(TCGv_i64 lo, TCGv_i64 hi, TCGv_i64 arg)

tcg/tcg-opc.h

@@ -147,6 +147,10 @@ DEF(rotl_i64, 1, 2, 0, IMPL64 | IMPL(TCG_TARGET_HAS_rot_i64))
 DEF(rotr_i64, 1, 2, 0, IMPL64 | IMPL(TCG_TARGET_HAS_rot_i64))
 DEF(deposit_i64, 1, 2, 2, IMPL64 | IMPL(TCG_TARGET_HAS_deposit_i64))
 
+DEF(trunc_shr_i32, 1, 1, 1,
+    IMPL(TCG_TARGET_HAS_trunc_shr_i32)
+    | (TCG_TARGET_REG_BITS == 32 ? TCG_OPF_NOT_PRESENT : 0))
+
 DEF(brcond_i64, 0, 2, 2, TCG_OPF_BB_END | IMPL64)
 DEF(ext8s_i64, 1, 1, 0, IMPL64 | IMPL(TCG_TARGET_HAS_ext8s_i64))
 DEF(ext16s_i64, 1, 1, 0, IMPL64 | IMPL(TCG_TARGET_HAS_ext16s_i64))

tcg/tcg.h

@@ -66,6 +66,7 @@ typedef uint64_t TCGRegSet;
 
 #if TCG_TARGET_REG_BITS == 32
 /* Turn some undef macros into false macros.  */
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 #define TCG_TARGET_HAS_div_i64          0
 #define TCG_TARGET_HAS_rem_i64          0
 #define TCG_TARGET_HAS_div2_i64         0

tcg/tci/tcg-target.h

@@ -82,6 +82,7 @@
 #define TCG_TARGET_HAS_mulsh_i32        0
 
 #if TCG_TARGET_REG_BITS == 64
+#define TCG_TARGET_HAS_trunc_shr_i32    0
 #define TCG_TARGET_HAS_bswap16_i64      1
 #define TCG_TARGET_HAS_bswap32_i64      1
 #define TCG_TARGET_HAS_bswap64_i64      1