[gcc r15-133] RISC-V: miscll comment fixes [NFC]

[Vineet Gupta <vineetg@gcc.gnu.org>]

https://gcc.gnu.org/g:467ca4a195e26dba77e7f62cc1a3d45a4e541c72

commit r15-133-g467ca4a195e26dba77e7f62cc1a3d45a4e541c72
Author: Vineet Gupta <vineetg@rivosinc.com>
Date:   Tue Mar 1 03:45:19 2022 -0800

    RISC-V: miscll comment fixes [NFC]
    
    gcc/ChangeLog:
            * config/riscv/riscv.cc: Comment updates.
            * config/riscv/riscv.h: Ditto.
    
    Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>

Diff:
---
 gcc/config/riscv/riscv.cc | 6 ++++--
 gcc/config/riscv/riscv.h  | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 8ed9df8126a..44945d47fd6 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -1258,7 +1258,9 @@ riscv_legitimate_constant_p (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
   return riscv_const_insns (x) > 0;
 }
 
-/* Implement TARGET_CANNOT_FORCE_CONST_MEM.  */
+/* Implement TARGET_CANNOT_FORCE_CONST_MEM.
+   Return true if X cannot (or should not) be spilled to the
+   constant pool.  */
 
 static bool
 riscv_cannot_force_const_mem (machine_mode mode ATTRIBUTE_UNUSED, rtx x)
@@ -8624,7 +8626,7 @@ riscv_modes_tieable_p (machine_mode mode1, machine_mode mode2)
 	       && GET_MODE_CLASS (mode2) == MODE_FLOAT));
 }
 
-/* Implement CLASS_MAX_NREGS.  */
+/* Implement TARGET_CLASS_MAX_NREGS.  */
 
 static unsigned char
 riscv_class_max_nregs (reg_class_t rclass, machine_mode mode)
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 7797e67317a..58d0b09bf7d 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -315,7 +315,7 @@ ASM_MISA_SPEC
 	- FRAME_POINTER_REGNUM
    - 1 vl register
    - 1 vtype register
-   - 30 unused registers for future expansion
+   - 28 unused registers for future expansion
    - 32 vector registers  */
 
 #define FIRST_PSEUDO_REGISTER 128