[PATCH] Fix typos in riscv register save/restore.

[Jim Wilson <jimw at sifive dot com>]

This patch fixes a few typos with computing registers to save/restore in
prologue/epilogue.  This fixes the github riscv/riscv-gcc issue #111.  The
typos are harmless, as these registers are call clobbered, but this was a
problem for one person modifying gcc for academic reasons, and hence the
typos need to be fixed.

Tested with a gcc make check, there were no regressions.  Committed.

	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.
---
 gcc/config/riscv/riscv.c | 6 +++---
 gcc/config/riscv/riscv.h | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index 5547d68..c7283d0 100644
--- a/gcc/config/riscv/riscv.c
+++ b/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);
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index fe09e84..feada72 100644
--- a/gcc/config/riscv/riscv.h
+++ b/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						\
-- 
2.7.4