[ARM/FDPIC v6 07/24] [ARM] FDPIC: Avoid saving/restoring r9 on stack since it is read-only

[Christophe Lyon <christophe.lyon@st.com>]

From: Christophe Lyon <christophe.lyon@linaro.org>

2019-XX-XX  Christophe Lyon  <christophe.lyon@st.com>
	Mickaël Guêné <mickael.guene@st.com>

	gcc/
	* config/arm/arm.h (PIC_REGISTER_MAY_NEED_SAVING): New helper.
	* config/arm/arm.c (arm_compute_save_reg0_reg12_mask): Handle
	FDPIC.

Change-Id: I0f3b2023ab2a2a0433dfe081dac6bbb194b7a76c

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index c34aab8..6ff3001 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -19571,9 +19571,7 @@ arm_compute_save_reg0_reg12_mask (void)
 	  save_reg_mask |= (1 << reg);
 
       /* Also save the pic base register if necessary.  */
-      if (flag_pic
-	  && !TARGET_SINGLE_PIC_BASE
-	  && arm_pic_register != INVALID_REGNUM
+      if (PIC_REGISTER_MAY_NEED_SAVING
 	  && crtl->uses_pic_offset_table)
 	save_reg_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;
     }
@@ -19605,9 +19603,7 @@ arm_compute_save_reg0_reg12_mask (void)
 
       /* If we aren't loading the PIC register,
 	 don't stack it even though it may be live.  */
-      if (flag_pic
-	  && !TARGET_SINGLE_PIC_BASE
-	  && arm_pic_register != INVALID_REGNUM
+      if (PIC_REGISTER_MAY_NEED_SAVING
 	  && (df_regs_ever_live_p (PIC_OFFSET_TABLE_REGNUM)
 	      || crtl->uses_pic_offset_table))
 	save_reg_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index e404e2c..490d22d 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -1960,6 +1960,13 @@ extern unsigned arm_pic_register;
 		   || label_mentioned_p (get_pool_constant (X)))))	\
 	 || tls_mentioned_p (X))
 
+/* We may want to save the PIC register if it is a dedicated one.  */
+#define PIC_REGISTER_MAY_NEED_SAVING			\
+  (flag_pic						\
+   && !TARGET_SINGLE_PIC_BASE				\
+   && !TARGET_FDPIC					\
+   && arm_pic_register != INVALID_REGNUM)
+
 /* We need to know when we are making a constant pool; this determines
    whether data needs to be in the GOT or can be referenced via a GOT
    offset.  */
-- 
2.6.3