[RFC PATCH 8/8] RISC-V: Cost model for ZBS extension.

[Kito Cheng]

2021-09-23 Kito Cheng <kito.ch...@sifive.com>

gcc/ChangeLog:

        * config/riscv/riscv.c (riscv_rtx_costs): Handle cost model
        for zbs extension.
---
 gcc/config/riscv/riscv.c | 47 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index 77981d8e818..055111ac30c 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -1851,6 +1851,24 @@ riscv_rtx_costs (rtx x, machine_mode mode, int 
outer_code, int opno ATTRIBUTE_UN
            *total = COSTS_N_INSNS (1);
            return true;
        }
+      /* bclri pattern for zbs.  */
+      if (TARGET_ZBS
+         && not_single_bit_mask_operand (XEXP (x, 1), VOIDmode))
+       {
+         *total = COSTS_N_INSNS (1);
+         return true;
+       }
+      /* bclr pattern for zbs.  */
+      if (TARGET_ZBS
+         && REG_P (XEXP (x, 1))
+         && GET_CODE (XEXP (x, 0)) == ROTATE
+         && CONST_INT_P (XEXP ((XEXP (x, 0)), 0))
+         && INTVAL (XEXP ((XEXP (x, 0)), 0)) == -2)
+       {
+         *total = COSTS_N_INSNS (1);
+         return true;
+       }
+
       gcc_fallthrough ();
     case IOR:
     case XOR:
@@ -1861,6 +1879,18 @@ riscv_rtx_costs (rtx x, machine_mode mode, int 
outer_code, int opno ATTRIBUTE_UN
          *total = riscv_binary_cost (x, 1, 2);
          return true;
        }
+
+      /* bset[i] and binv[i] pattern for zbs.  */
+      if ((GET_CODE (x) == IOR || GET_CODE (x) == XOR)
+         && TARGET_ZBS
+         && ((GET_CODE (XEXP (x, 0)) == ASHIFT
+             && CONST_INT_P (XEXP (XEXP (x, 0), 0)))
+             || single_bit_mask_operand (XEXP (x, 1), VOIDmode)))
+       {
+         *total = COSTS_N_INSNS (1);
+         return true;
+       }
+
       /* Double-word operations use two single-word operations.  */
       *total = riscv_binary_cost (x, 1, 2);
       return false;
@@ -1876,9 +1906,26 @@ riscv_rtx_costs (rtx x, machine_mode mode, int 
outer_code, int opno ATTRIBUTE_UN
          *total = COSTS_N_INSNS (SINGLE_SHIFT_COST);
          return true;
        }
+      /* bext pattern for zbs.  */
+      if (TARGET_ZBS && outer_code == SET
+         && GET_CODE (XEXP (x, 1)) == CONST_INT
+         && INTVAL (XEXP (x, 1)) == 1)
+       {
+         *total = COSTS_N_INSNS (SINGLE_SHIFT_COST);
+         return true;
+       }
       return false;
 
     case ASHIFT:
+      /* bset pattern for zbs.  */
+      if (TARGET_ZBS
+         && CONST_INT_P (XEXP (x, 0))
+         && INTVAL (XEXP (x, 0)) == 1)
+       {
+         *total = COSTS_N_INSNS (1);
+         return true;
+       }
+      gcc_fallthrough ();
     case ASHIFTRT:
     case LSHIFTRT:
       *total = riscv_binary_cost (x, SINGLE_SHIFT_COST,
-- 
2.33.0