The following patch fixes a problem with allocating the same stack slots
to conflicting pseudos. The problem exists only for AVR LRA port.
The patch was successfully bootstrapped and tested on x86-64 and aarch64.
commit c024867d1aa9d465e0236fc9d45d8e1d4bb6bd30
Author: Vladimir N. Makarov <vmaka...@redhat.com>
Date: Thu Aug 17 11:57:45 2023 -0400
[LRA]: When assigning stack slots to pseudos previously assigned to fp
consider other spilled pseudos
The previous LRA patch can assign slot of conflicting pseudos to
pseudos spilled after prohibiting fp->sp elimination. This patch
fixes this problem.
gcc/ChangeLog:
* lra-spills.cc (assign_stack_slot_num_and_sort_pseudos): Moving
slots_num initialization from here ...
(lra_spill): ... to here before the 1st call of
assign_stack_slot_num_and_sort_pseudos. Add the 2nd call after
fp->sp elimination.
diff --git a/gcc/lra-spills.cc b/gcc/lra-spills.cc
index 7e1d35b5e4e..a663a1931e3 100644
--- a/gcc/lra-spills.cc
+++ b/gcc/lra-spills.cc
@@ -363,7 +363,6 @@ assign_stack_slot_num_and_sort_pseudos (int *pseudo_regnos,
int n)
{
int i, j, regno;
- slots_num = 0;
/* Assign stack slot numbers to spilled pseudos, use smaller numbers
for most frequently used pseudos. */
for (i = 0; i < n; i++)
@@ -628,6 +627,7 @@ lra_spill (void)
/* Sort regnos according their usage frequencies. */
qsort (pseudo_regnos, n, sizeof (int), regno_freq_compare);
n = assign_spill_hard_regs (pseudo_regnos, n);
+ slots_num = 0;
assign_stack_slot_num_and_sort_pseudos (pseudo_regnos, n);
for (i = 0; i < n; i++)
if (pseudo_slots[pseudo_regnos[i]].mem == NULL_RTX)
@@ -635,6 +635,7 @@ lra_spill (void)
if ((n2 = lra_update_fp2sp_elimination (pseudo_regnos)) > 0)
{
/* Assign stack slots to spilled pseudos assigned to fp. */
+ assign_stack_slot_num_and_sort_pseudos (pseudo_regnos, n2);
for (i = 0; i < n2; i++)
if (pseudo_slots[pseudo_regnos[i]].mem == NULL_RTX)
assign_mem_slot (pseudo_regnos[i]);