My earlier change for making the compiler prefer
POP {PC}
over
LDR PC, [SP], #4
had a slightly unexpected consequence in that we now also call
arm_emit_multi_reg_pop to handle single register pops when the
register is not PC. This exposed a latent bug in this function where
the dwarf unwinding notes on the single-register POP were not being
set correctly.
gcc/
PR target/118089
* config/arm/arm.cc (arm_emit_multi_reg_pop): Add a CFA adjust
note to single-register POP instructions.
---
gcc/config/arm/arm.cc | 51 +++++++++++++++++++++++--------------------
1 file changed, 27 insertions(+), 24 deletions(-)
diff --git a/gcc/config/arm/arm.cc b/gcc/config/arm/arm.cc
index 7e2082101d8..503401544cb 100644
--- a/gcc/config/arm/arm.cc
+++ b/gcc/config/arm/arm.cc
@@ -22563,7 +22563,8 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
/* The parallel needs to hold num_regs SETs
and one SET for the stack update. */
- par = gen_rtx_PARALLEL (VOIDmode, rtvec_alloc (num_regs + emit_update +
offset_adj));
+ par = gen_rtx_PARALLEL (VOIDmode,
+ rtvec_alloc (num_regs + emit_update + offset_adj));
if (return_in_pc)
XVECEXP (par, 0, 0) = ret_rtx;
@@ -22571,11 +22572,11 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
if (emit_update)
{
/* Increment the stack pointer, based on there being
- num_regs 4-byte registers to restore. */
+ num_regs 4-byte registers to restore. */
tmp = gen_rtx_SET (stack_pointer_rtx,
- plus_constant (Pmode,
- stack_pointer_rtx,
- 4 * num_regs));
+ plus_constant (Pmode,
+ stack_pointer_rtx,
+ 4 * num_regs));
RTX_FRAME_RELATED_P (tmp) = 1;
XVECEXP (par, 0, offset_adj) = tmp;
}
@@ -22587,31 +22588,33 @@ arm_emit_multi_reg_pop (unsigned long saved_regs_mask)
rtx dwarf_reg = reg = gen_rtx_REG (SImode, i);
if (arm_current_function_pac_enabled_p () && i == IP_REGNUM)
dwarf_reg = gen_rtx_REG (SImode, RA_AUTH_CODE);
- if ((num_regs == 1) && emit_update && !return_in_pc)
- {
- /* Emit single load with writeback. */
- tmp = gen_frame_mem (SImode,
- gen_rtx_POST_INC (Pmode,
- stack_pointer_rtx));
- tmp = emit_insn (gen_rtx_SET (reg, tmp));
+ if ((num_regs == 1) && emit_update && !return_in_pc)
+ {
+ /* Emit single load with writeback. */
+ tmp = gen_frame_mem (SImode,
+ gen_rtx_POST_INC (Pmode,
+ stack_pointer_rtx));
+ tmp = emit_insn (gen_rtx_SET (reg, tmp));
REG_NOTES (tmp) = alloc_reg_note (REG_CFA_RESTORE, dwarf_reg,
dwarf);
- return;
- }
+ arm_add_cfa_adjust_cfa_note (tmp, UNITS_PER_WORD,
+ stack_pointer_rtx, stack_pointer_rtx);
+ return;
+ }
- tmp = gen_rtx_SET (reg,
- gen_frame_mem
- (SImode,
- plus_constant (Pmode, stack_pointer_rtx, 4 * j)));
- RTX_FRAME_RELATED_P (tmp) = 1;
- XVECEXP (par, 0, j + emit_update + offset_adj) = tmp;
+ tmp = gen_rtx_SET (reg,
+ gen_frame_mem
+ (SImode,
+ plus_constant (Pmode, stack_pointer_rtx, 4 * j)));
+ RTX_FRAME_RELATED_P (tmp) = 1;
+ XVECEXP (par, 0, j + emit_update + offset_adj) = tmp;
- /* We need to maintain a sequence for DWARF info too. As dwarf info
- should not have PC, skip PC. */
- if (i != PC_REGNUM)
+ /* We need to maintain a sequence for DWARF info too. As dwarf info
+ should not have PC, skip PC. */
+ if (i != PC_REGNUM)
dwarf = alloc_reg_note (REG_CFA_RESTORE, dwarf_reg, dwarf);
- j++;
+ j++;
}
if (return_in_pc)
--
2.34.1
