No need for thread pointer in bare metal toolchain. Use TP register normally.
gcc/
2016-09-29 Claudiu Zissulescu <claz...@synopsys.com>
* config/arc/elf.h (ARGET_ARC_TP_REGNO_DEFAULT): Define.
* config/arc/linux.h (ARGET_ARC_TP_REGNO_DEFAULT): Likewise.
* config/arc/arc.opt (mtp-regno): Use ARGET_ARC_TP_REGNO_DEFAULT.
---
gcc/config/arc/arc.opt | 2 +-
gcc/config/arc/elf.h | 5 +++++
gcc/config/arc/linux.h | 4 ++++
3 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/gcc/config/arc/arc.opt b/gcc/config/arc/arc.opt
index 17af736..6060ded 100644
--- a/gcc/config/arc/arc.opt
+++ b/gcc/config/arc/arc.opt
@@ -469,7 +469,7 @@ EnumValue
Enum(arc_fpu) String(fpud_all) Value(FPU_FPUD_ALL)
mtp-regno=
-Target RejectNegative Joined UInteger Var(arc_tp_regno) Init(25)
+Target RejectNegative Joined UInteger Var(arc_tp_regno)
Init(TARGET_ARC_TP_REGNO_DEFAULT)
Specify thread pointer register number.
mtp-regno=none
diff --git a/gcc/config/arc/elf.h b/gcc/config/arc/elf.h
index d2106c5..a6d6c05 100644
--- a/gcc/config/arc/elf.h
+++ b/gcc/config/arc/elf.h
@@ -53,3 +53,8 @@ along with GCC; see the file COPYING3. If not see
# define MULTILIB_DEFAULTS { "mcpu=" ARC_MULTILIB_CPU_DEFAULT }
# endif
#endif
+
+/* Bare-metal toolchains are not having a thread pointer register
+ set. */
+#undef TARGET_ARC_TP_REGNO_DEFAULT
+#define TARGET_ARC_TP_REGNO_DEFAULT -1
diff --git a/gcc/config/arc/linux.h b/gcc/config/arc/linux.h
index 10c291c..1d10357 100644
--- a/gcc/config/arc/linux.h
+++ b/gcc/config/arc/linux.h
@@ -74,3 +74,7 @@ along with GCC; see the file COPYING3. If not see
/* We do not have any MULTILIB_OPTIONS specified, so there are no
MULTILIB_DEFAULTS. */
#undef MULTILIB_DEFAULTS
+
+/* Linux toolchains are using r25 as TLS register. */
+#undef TARGET_ARC_TP_REGNO_DEFAULT
+#define TARGET_ARC_TP_REGNO_DEFAULT 25
--
1.9.1
