Re: [ARM/FDPIC v2 07/21] [ARM] FDPIC: Avoid saving/restoring r9 on stack since it is RO

[Kyrill Tkachov]

Hi Christophe,

On 13/07/18 17:11, christophe.l...@st.com wrote:

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

2018-XX-XX  Christophe Lyon  <christophe.l...@st.com>
        Mickaël Guêné <mickael.gu...@st.com>

        gcc/
        * config/arm/arm.c (arm_compute_save_reg0_reg12_mask): Handle
        FDPIC.
        (thumb1_compute_save_core_reg_mask): Likewise.

Change-Id: Ib534cf91704cdc740867b46a8fe45fda27894562

diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index 44c3b08..c9f391b 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -19486,7 +19486,7 @@ arm_compute_save_reg0_reg12_mask (void)

       /* Also save the pic base register if necessary.  */
       if (flag_pic
-         && !TARGET_SINGLE_PIC_BASE
+         && !TARGET_SINGLE_PIC_BASE && !TARGET_FDPIC
           && arm_pic_register != INVALID_REGNUM
           && crtl->uses_pic_offset_table)
         save_reg_mask |= 1 << PIC_OFFSET_TABLE_REGNUM;
@@ -19520,7 +19520,7 @@ 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
+         && !TARGET_SINGLE_PIC_BASE && !TARGET_FDPIC
           && arm_pic_register != INVALID_REGNUM
           && (df_regs_ever_live_p (PIC_OFFSET_TABLE_REGNUM)
               || crtl->uses_pic_offset_table))
@@ -19689,7 +19689,7 @@ thumb1_compute_save_core_reg_mask (void)
     mask |= 1 << HARD_FRAME_POINTER_REGNUM;

   if (flag_pic
-      && !TARGET_SINGLE_PIC_BASE
+      && !TARGET_SINGLE_PIC_BASE && !TARGET_FDPIC
       && arm_pic_register != INVALID_REGNUM
       && crtl->uses_pic_offset_table)
     mask |= 1 << PIC_OFFSET_TABLE_REGNUM;

Is this change necessary? FDPIC is only supported for Armv7 onwards, so the 
Thumb1 path shouldn't be called?

Thanks,
Kyrill

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2.6.3