When propagating a multi-word register into an access with a smaller
mode the can_change_mode backend hook is already consulted for the
original register. This however is also required for the intermediate
copy in copy_regno which might use a different register class.
Bootstrapped on x86_64 and s390x. No testsuite regressions.
Ok for mainline?
gcc/ChangeLog:
PR rtl-optimization/101260
* regcprop.cc (maybe_mode_change): Invoke mode_change_ok also for
copy_regno.
---
gcc/regcprop.cc | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/gcc/regcprop.cc b/gcc/regcprop.cc
index 1a9bcf0a1ad..8e966f2b5ac 100644
--- a/gcc/regcprop.cc
+++ b/gcc/regcprop.cc
@@ -426,7 +426,8 @@ maybe_mode_change (machine_mode orig_mode, machine_mode
copy_mode,
if (orig_mode == new_mode)
return gen_raw_REG (new_mode, regno);
- else if (mode_change_ok (orig_mode, new_mode, regno))
+ else if (mode_change_ok (orig_mode, new_mode, regno)
+ && mode_change_ok (copy_mode, new_mode, copy_regno))
{
int copy_nregs = hard_regno_nregs (copy_regno, copy_mode);
int use_nregs = hard_regno_nregs (copy_regno, new_mode);
--
2.34.1
