This fixes a typo in combine_reg_notes in the load/store pair fusion
pass. As it stands, the calls to filter_notes store any
REG_FRAME_RELATED_EXPR to fr_expr with the following association:
- i2 -> fr_expr[0]
- i1 -> fr_expr[1]
but then the checks inside the following if statement expect the
opposite (more natural) association, i.e.:
- i2 -> fr_expr[1]
- i1 -> fr_expr[0]
this patch fixes the oversight by swapping the fr_expr indices in the
calls to filter_notes.
In hindsight it would probably have been less confusing / error-prone to
have combine_reg_notes take an array of two insns, then we wouldn't have
to mix 1-based and 0-based indexing as well as remembering to call
filter_notes in reverse program order. This however is a minimal fix
for backporting purposes.
Many thanks to Matthew for spotting this typo and pointing it out to me.
Bootstrapped/regtested on aarch64-linux-gnu, OK for trunk and the 14
branch after the 14.1 release?
Thanks,
Alex
gcc/ChangeLog:
PR target/114936
* config/aarch64/aarch64-ldp-fusion.cc (combine_reg_notes):
Ensure insn iN has its REG_FRAME_RELATED_EXPR (if any) stored in
FR_EXPR[N-1], thus matching the correspondence expected by the
copy_rtx calls.
diff --git a/gcc/config/aarch64/aarch64-ldp-fusion.cc
b/gcc/config/aarch64/aarch64-ldp-fusion.cc
index 0bc225dae7b..12ef305d8d3 100644
--- a/gcc/config/aarch64/aarch64-ldp-fusion.cc
+++ b/gcc/config/aarch64/aarch64-ldp-fusion.cc
@@ -1085,9 +1085,9 @@ combine_reg_notes (insn_info *i1, insn_info *i2, bool
load_p)
bool found_eh_region = false;
rtx result = NULL_RTX;
result = filter_notes (REG_NOTES (i2->rtl ()), result,
- &found_eh_region, fr_expr);
- result = filter_notes (REG_NOTES (i1->rtl ()), result,
&found_eh_region, fr_expr + 1);
+ result = filter_notes (REG_NOTES (i1->rtl ()), result,
+ &found_eh_region, fr_expr);
if (!load_p)
{
