Fix typos in riscv register save/restore.

	gcc/
	* config/riscv/riscv.c (riscv_for_each_saved_reg): Use GP_REG_LAST
	instead of GP_REG_LAST-1.
	(riscv_adjust_libcall_cfi_prologue): Likewise.
	(riscv_adjust_libcall_cri_epilogue): Likewise.
	* config/riscv/riscv.h (CALL_USED_REGISTERS): Change a6 to t6 in
	comment.

From-SVN: r255389

gcc/ChangeLog

+2017-12-04  Jim Wilson  <jimw@sifive.com>
+
+	* config/riscv/riscv.c (riscv_for_each_saved_reg): Use GP_REG_LAST
+	instead of GP_REG_LAST-1.
+	(riscv_adjust_libcall_cfi_prologue): Likewise.
+	(riscv_adjust_libcall_cri_epilogue): Likewise.
+	* config/riscv/riscv.h (CALL_USED_REGISTERS): Change a6 to t6 in
+	comment.
+
 2017-12-04  Luis Machado  <luis.machado@linaro.org>
 
 	* ipa-pure-const.c (check_decl): Add missing newline.

gcc/config/riscv/riscv.c

@@ -3336,7 +3336,7 @@ riscv_for_each_saved_reg (HOST_WIDE_INT sp_offset, riscv_save_restore_fn fn)
 
   /* Save the link register and s-registers. */
   offset = cfun->machine->frame.gp_sp_offset - sp_offset;
-  for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST-1; regno++)
+  for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST; regno++)
     if (BITSET_P (cfun->machine->frame.mask, regno - GP_REG_FIRST))
       {
 	riscv_save_restore_reg (word_mode, regno, offset, fn);
@@ -3424,7 +3424,7 @@ riscv_adjust_libcall_cfi_prologue ()
   int saved_size = cfun->machine->frame.save_libcall_adjustment;
   int offset;
 
-  for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST-1; regno++)
+  for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST; regno++)
     if (BITSET_P (cfun->machine->frame.mask, regno - GP_REG_FIRST))
       {
 	/* The save order is ra, s0, s1, s2 to s11.  */
@@ -3552,7 +3552,7 @@ riscv_adjust_libcall_cfi_epilogue ()
   dwarf = alloc_reg_note (REG_CFA_ADJUST_CFA, adjust_sp_rtx,
 			  dwarf);
 
-  for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST-1; regno++)
+  for (int regno = GP_REG_FIRST; regno <= GP_REG_LAST; regno++)
     if (BITSET_P (cfun->machine->frame.mask, regno - GP_REG_FIRST))
       {
 	reg = gen_rtx_REG (SImode, regno);

gcc/config/riscv/riscv.h

@@ -233,7 +233,7 @@ along with GCC; see the file COPYING3.  If not see
   1, 1									\
 }
 
-/* a0-a7, t0-a6, fa0-fa7, and ft0-ft11 are volatile across calls.
+/* a0-a7, t0-t6, fa0-fa7, and ft0-ft11 are volatile across calls.
    The call RTLs themselves clobber ra.  */
 
 #define CALL_USED_REGISTERS						\