This bug is exposed by FRE refactor of r263875. Comparing the fre
dump file shows no obvious change of the segment fault function proves
it to be a target issue.
frame_pointer_needed is set to true in reload pass setup_can_eliminate,
but regs_ever_live[31] is false, pro_and_epilogue uses it without live
check causing CPU2006 465.tonto segment fault of loading from invalid
addresses due to r31 not saved/restored. Thus, add HARD_FRAME_POINTER_REGNUM
live check with frame_pointer_needed_indeed_p when generating pro_and_epilogue
instructions.
Bootstrap and regression tested pass on Power8-LE. Backport to gcc-9
required once approved.
gcc/ChangeLog
2020-04-13 Xiong Hu Luo <luo...@linux.ibm.com>
PR target/91518
* config/rs6000/rs6000-logue.c (frame_pointer_needed_indeed_p):
New function.
(rs6000_emit_prologue_components):
Check with frame_pointer_needed_indeed_p.
(rs6000_emit_epilogue_components): Likewise.
(rs6000_emit_prologue): Likewise.
(rs6000_emit_epilogue): Likewise.
---
gcc/config/rs6000/rs6000-logue.c | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/gcc/config/rs6000/rs6000-logue.c b/gcc/config/rs6000/rs6000-logue.c
index 4cbf228eb79..d17876ac0fb 100644
--- a/gcc/config/rs6000/rs6000-logue.c
+++ b/gcc/config/rs6000/rs6000-logue.c
@@ -2730,14 +2730,22 @@ rs6000_disqualify_components (sbitmap components, edge
e,
}
}
+/* Determine whether HARD_FRAM_POINTER_REGNUM is really needed. */
+static bool
+frame_pointer_needed_indeed_p (void)
+{
+ return frame_pointer_needed
+ && df_regs_ever_live_p (HARD_FRAME_POINTER_REGNUM);
+}
+
/* Implement TARGET_SHRINK_WRAP_EMIT_PROLOGUE_COMPONENTS. */
void
rs6000_emit_prologue_components (sbitmap components)
{
rs6000_stack_t *info = rs6000_stack_info ();
- rtx ptr_reg = gen_rtx_REG (Pmode, frame_pointer_needed
- ? HARD_FRAME_POINTER_REGNUM
- : STACK_POINTER_REGNUM);
+ rtx ptr_reg = gen_rtx_REG (Pmode, frame_pointer_needed_indeed_p ()
+ ? HARD_FRAME_POINTER_REGNUM
+ : STACK_POINTER_REGNUM);
machine_mode reg_mode = Pmode;
int reg_size = TARGET_32BIT ? 4 : 8;
@@ -2815,9 +2823,9 @@ void
rs6000_emit_epilogue_components (sbitmap components)
{
rs6000_stack_t *info = rs6000_stack_info ();
- rtx ptr_reg = gen_rtx_REG (Pmode, frame_pointer_needed
- ? HARD_FRAME_POINTER_REGNUM
- : STACK_POINTER_REGNUM);
+ rtx ptr_reg = gen_rtx_REG (Pmode, frame_pointer_needed_indeed_p ()
+ ? HARD_FRAME_POINTER_REGNUM
+ : STACK_POINTER_REGNUM);
machine_mode reg_mode = Pmode;
int reg_size = TARGET_32BIT ? 4 : 8;
@@ -3658,7 +3666,7 @@ rs6000_emit_prologue (void)
}
/* Set frame pointer, if needed. */
- if (frame_pointer_needed)
+ if (frame_pointer_needed_indeed_p ())
{
insn = emit_move_insn (gen_rtx_REG (Pmode, HARD_FRAME_POINTER_REGNUM),
sp_reg_rtx);
@@ -4534,7 +4542,7 @@ rs6000_emit_epilogue (enum epilogue_type epilogue_type)
}
/* If we have a frame pointer, we can restore the old stack pointer
from it. */
- else if (frame_pointer_needed)
+ else if (frame_pointer_needed_indeed_p ())
{
frame_reg_rtx = sp_reg_rtx;
if (DEFAULT_ABI == ABI_V4)
--
2.21.0.777.g83232e3864
