[PATCH 11/15] tcg/riscv: Do not accept immediate operands for sub

[Richard Henderson <richard.henderson@linaro.org>]

The transformations to neg and add immediate are now done
generically and need not be handled by the backend.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 tcg/riscv/tcg-target-con-set.h |  2 +-
 tcg/riscv/tcg-target-con-str.h |  1 -
 tcg/riscv/tcg-target.c.inc     | 24 ++++--------------------
 3 files changed, 5 insertions(+), 22 deletions(-)

diff --git a/tcg/riscv/tcg-target-con-set.h b/tcg/riscv/tcg-target-con-set.h
index 0f72281a08..13a383aeb1 100644
--- a/tcg/riscv/tcg-target-con-set.h
+++ b/tcg/riscv/tcg-target-con-set.h
@@ -13,9 +13,9 @@ C_O0_I1(r)
 C_O0_I2(rZ, r)
 C_O0_I2(rZ, rZ)
 C_O1_I1(r, r)
+C_O1_I2(r, r, r)
 C_O1_I2(r, r, ri)
 C_O1_I2(r, r, rI)
-C_O1_I2(r, rZ, rN)
 C_O1_I2(r, rZ, rZ)
 C_N1_I2(r, r, rM)
 C_O1_I4(r, r, rI, rM, rM)
diff --git a/tcg/riscv/tcg-target-con-str.h b/tcg/riscv/tcg-target-con-str.h
index 6f1cfb976c..a8d57c0e37 100644
--- a/tcg/riscv/tcg-target-con-str.h
+++ b/tcg/riscv/tcg-target-con-str.h
@@ -15,6 +15,5 @@ REGS('r', ALL_GENERAL_REGS)
  * CONST(letter, TCG_CT_CONST_* bit set)
  */
 CONST('I', TCG_CT_CONST_S12)
-CONST('N', TCG_CT_CONST_N12)
 CONST('M', TCG_CT_CONST_M12)
 CONST('Z', TCG_CT_CONST_ZERO)
diff --git a/tcg/riscv/tcg-target.c.inc b/tcg/riscv/tcg-target.c.inc
index 2b889486e4..6b28f2f85d 100644
--- a/tcg/riscv/tcg-target.c.inc
+++ b/tcg/riscv/tcg-target.c.inc
@@ -136,8 +136,7 @@ static TCGReg tcg_target_call_oarg_reg(TCGCallReturnKind kind, int slot)
 
 #define TCG_CT_CONST_ZERO  0x100
 #define TCG_CT_CONST_S12   0x200
-#define TCG_CT_CONST_N12   0x400
-#define TCG_CT_CONST_M12   0x800
+#define TCG_CT_CONST_M12   0x400
 
 #define ALL_GENERAL_REGS   MAKE_64BIT_MASK(0, 32)
 
@@ -160,13 +159,6 @@ static bool tcg_target_const_match(int64_t val, int ct,
     if ((ct & TCG_CT_CONST_S12) && val >= -0x800 && val <= 0x7ff) {
         return 1;
     }
-    /*
-     * Sign extended from 12 bits, negated: [-0x7ff, 0x800].
-     * Used for subtraction, where a constant must be handled by ADDI.
-     */
-    if ((ct & TCG_CT_CONST_N12) && val >= -0x7ff && val <= 0x800) {
-        return 1;
-    }
     /*
      * Sign extended from 12 bits, +/- matching: [-0x7ff, 0x7ff].
      * Used by addsub2 and movcond, which may need the negative value,
@@ -1559,18 +1551,10 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
         break;
 
     case INDEX_op_sub_i32:
-        if (c2) {
-            tcg_out_opc_imm(s, OPC_ADDIW, a0, a1, -a2);
-        } else {
-            tcg_out_opc_reg(s, OPC_SUBW, a0, a1, a2);
-        }
+        tcg_out_opc_reg(s, OPC_SUBW, a0, a1, a2);
         break;
     case INDEX_op_sub_i64:
-        if (c2) {
-            tcg_out_opc_imm(s, OPC_ADDI, a0, a1, -a2);
-        } else {
-            tcg_out_opc_reg(s, OPC_SUB, a0, a1, a2);
-        }
+        tcg_out_opc_reg(s, OPC_SUB, a0, a1, a2);
         break;
 
     case INDEX_op_and_i32:
@@ -1945,7 +1929,7 @@ static TCGConstraintSetIndex tcg_target_op_def(TCGOpcode op)
 
     case INDEX_op_sub_i32:
     case INDEX_op_sub_i64:
-        return C_O1_I2(r, rZ, rN);
+        return C_O1_I2(r, r, r);
 
     case INDEX_op_andc_i32:
     case INDEX_op_andc_i64:
-- 
2.34.1