The one for the prologue mflr did not have any value set, which means
use the SET that is in the insn pattern. This works fine, except when
some late pass decides to replace the SET_SRC -- this changes the
meaning of the REG_CFA_REGISTER! Such passes should not do these
things, but let's be more explicit here, for extra robustness. It
could be argued that this defaulting is a design misfeature (it does
not save much space either, etc.)
Bootstrapped and tested on powerpc64-linux {-m32,-m64}. I'll commit
this together with the rest of the series.
Segher
2018-05-08 Segher Boessenkool <seg...@kernel.crashing.org>
PR rtl-optimization/85645
* config/rs6000/rs6000.c (rs6000_emit_prologue_components): Put a SET
in the REG_CFA_REGISTER note for LR, don't leave it empty.
---
gcc/config/rs6000/rs6000.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c
index 1b2bb12..6118423 100644
--- a/gcc/config/rs6000/rs6000.c
+++ b/gcc/config/rs6000/rs6000.c
@@ -26151,10 +26151,11 @@ rs6000_emit_prologue_components (sbitmap components)
/* Prologue for LR. */
if (bitmap_bit_p (components, 0))
{
+ rtx lr = gen_rtx_REG (reg_mode, LR_REGNO);
rtx reg = gen_rtx_REG (reg_mode, 0);
- rtx_insn *insn = emit_move_insn (reg, gen_rtx_REG (reg_mode, LR_REGNO));
+ rtx_insn *insn = emit_move_insn (reg, lr);
RTX_FRAME_RELATED_P (insn) = 1;
- add_reg_note (insn, REG_CFA_REGISTER, NULL);
+ add_reg_note (insn, REG_CFA_REGISTER, gen_rtx_SET (reg, lr));
int offset = info->lr_save_offset;
if (info->push_p)
@@ -26162,7 +26163,6 @@ rs6000_emit_prologue_components (sbitmap components)
insn = emit_insn (gen_frame_store (reg, ptr_reg, offset));
RTX_FRAME_RELATED_P (insn) = 1;
- rtx lr = gen_rtx_REG (reg_mode, LR_REGNO);
rtx mem = copy_rtx (SET_DEST (single_set (insn)));
add_reg_note (insn, REG_CFA_OFFSET, gen_rtx_SET (mem, lr));
}
--
1.8.3.1
