[gcc r12-4848] RISC-V: Fix build errors with shNadd/shNadd.uw patterns in zba cost model

[Maciej W. Rozycki <macro@gcc.gnu.org>]

https://gcc.gnu.org/g:c33a5cc9e7f1475108892abb147f9382ecbaec12

commit r12-4848-gc33a5cc9e7f1475108892abb147f9382ecbaec12
Author: Maciej W. Rozycki <macro@embecosm.com>
Date:   Tue Nov 2 16:05:00 2021 +0000

    RISC-V: Fix build errors with shNadd/shNadd.uw patterns in zba cost model
    
    Fix a build regression from commit 04a9b554ba1a ("RISC-V: Cost model
    for zba extension."):
    
    .../gcc/config/riscv/riscv.c: In function 'bool riscv_rtx_costs(rtx, machine_mode, int, int, int*, bool)':
    .../gcc/config/riscv/riscv.c:2018:11: error: 'and' of mutually exclusive equal-tests is always 0 [-Werror]
     2018 |           && IN_RANGE (INTVAL (XEXP (XEXP (x, 0), 0)), 1, 3))
          |           ^~
    .../gcc/config/riscv/riscv.c:2047:17: error: unused variable 'ashift_lhs' [-Werror=unused-variable]
     2047 |             rtx ashift_lhs = XEXP (and_lhs, 0);
          |                 ^~~~~~~~~~
    
    by correcting a CONST_INT_P check referring the wrong operand and
    getting rid of the unused variable.
    
            gcc/
            * config/riscv/riscv.c (riscv_rtx_costs): Correct a CONST_INT_P
            check and remove an unused local variable with shNadd/shNadd.uw
            pattern handling.

Diff:
---
 gcc/config/riscv/riscv.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index 6aef3d3a6cf..5387bfc18aa 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -2014,8 +2014,8 @@ riscv_rtx_costs (rtx x, machine_mode mode, int outer_code, int opno ATTRIBUTE_UN
 	      (TARGET_64BIT && (mode == DImode)))
 	  && (GET_CODE (XEXP (x, 0)) == ASHIFT)
 	  && REG_P (XEXP (XEXP (x, 0), 0))
-	  && CONST_INT_P (XEXP (XEXP (x, 0), 0))
-	  && IN_RANGE (INTVAL (XEXP (XEXP (x, 0), 0)), 1, 3))
+	  && CONST_INT_P (XEXP (XEXP (x, 0), 1))
+	  && IN_RANGE (INTVAL (XEXP (XEXP (x, 0), 1)), 1, 3))
 	{
 	  *total = COSTS_N_INSNS (1);
 	  return true;
@@ -2044,7 +2044,6 @@ riscv_rtx_costs (rtx x, machine_mode mode, int outer_code, int opno ATTRIBUTE_UN
 	    if (!CONST_INT_P (and_rhs))
 	      break;
 
-	    rtx ashift_lhs = XEXP (and_lhs, 0);
 	    rtx ashift_rhs = XEXP (and_lhs, 1);
 
 	    if (!CONST_INT_P (ashift_rhs)