[PATCH v2] RISC-V: Add vector_scalar_shift_operand

[Palmer Dabbelt <palmer@rivosinc.com>]

The vector shift immediates happen to have the same constraints as some
of the CSR-related operands, but it's a different usage.  This adds a
name for them, so I don't get confused again next time.

gcc/ChangeLog:

	* config/riscv/autovec.md (shifts): Use
	  vector_scalar_shift_operand.
	* config/riscv/predicates.md (vector_scalar_shift_operand): New
	  predicate.
---
Still haven't built-tested it, my box is busy.

Changes since v1 <20230511182555.26183-1-palmer@rivosinc.com>:
* Change the name to "vector_scalar_shift_operand", as per Juzhe's
  suggestion.
* Add a missing second ";" in the comment.
---
 gcc/config/riscv/autovec.md    | 2 +-
 gcc/config/riscv/predicates.md | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/gcc/config/riscv/autovec.md b/gcc/config/riscv/autovec.md
index ac0c939d277..4561fcbe957 100644
--- a/gcc/config/riscv/autovec.md
+++ b/gcc/config/riscv/autovec.md
@@ -132,7 +132,7 @@ (define_expand "<optab><mode>3"
   [(set (match_operand:VI 0 "register_operand")
     (any_shift:VI
      (match_operand:VI 1 "register_operand")
-     (match_operand:<VEL> 2 "csr_operand")))]
+     (match_operand:<VEL> 2 "vector_scalar_shift_operand")))]
   "TARGET_VECTOR"
 {
   if (!CONST_SCALAR_INT_P (operands[2]))
diff --git a/gcc/config/riscv/predicates.md b/gcc/config/riscv/predicates.md
index e5adf06fa25..90e6f942c97 100644
--- a/gcc/config/riscv/predicates.md
+++ b/gcc/config/riscv/predicates.md
@@ -43,6 +43,11 @@ (define_predicate "csr_operand"
   (ior (match_operand 0 "const_csr_operand")
        (match_operand 0 "register_operand")))
 
+;; V has 32-bit unsigned immediates.  This happens to be the same constraint as
+;; the csr_operand, but it's not CSR related.
+(define_predicate "vector_scalar_shift_operand"
+  (match_operand 0 "csr_operand"))
+
 (define_predicate "sle_operand"
   (and (match_code "const_int")
        (match_test "SMALL_OPERAND (INTVAL (op) + 1)")))
-- 
2.40.0