On 2026/05/09 18:58, Max Filippov wrote:
I see that code generated with this change for the call0 ABI
clobbers callee-saved registers.
It seems I misunderstood how `validate_change()` works.
Also, this has raised a new concern, so I will post another patch later.
--- >8 ---
No functional changes.
gcc/ChangeLog:
* config/xtensa/xtensa.cc
(xtensa_can_eliminate_callee_saved_reg_p):
Change the arguments that return values from being passed by pointer
to C++ reference.
(xtensa_expand_prologue):
Adjust the call to xtensa_can_eliminate_callee_saved_reg_p() to
match the above changes.
---
gcc/config/xtensa/xtensa.cc | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
index 212086e4e4c..82c0f38f304 100644
--- a/gcc/config/xtensa/xtensa.cc
+++ b/gcc/config/xtensa/xtensa.cc
@@ -3614,17 +3614,16 @@ xtensa_emit_adjust_stack_ptr (HOST_WIDE_INT offset, int
flags)
static bool
xtensa_can_eliminate_callee_saved_reg_p (unsigned int regno,
- rtx_insn **p_insnS,
- rtx_insn **p_insnR)
+ rtx_insn *&insnS, rtx_insn *&insnR)
{
df_ref ref;
- rtx_insn *insn, *insnS = NULL, *insnR = NULL;
+ rtx_insn *insn;
rtx pattern;
if (!optimize || !df || call_used_or_fixed_reg_p (regno))
return false;
- for (ref = DF_REG_DEF_CHAIN (regno);
+ for (insnS = NULL, ref = DF_REG_DEF_CHAIN (regno);
ref; ref = DF_REF_NEXT_REG (ref))
if (DF_REF_CLASS (ref) != DF_REF_REGULAR
|| DEBUG_INSN_P (insn = DF_REF_INSN (ref)))
@@ -3644,7 +3643,7 @@ xtensa_can_eliminate_callee_saved_reg_p (unsigned int
regno,
else
return false;
- for (ref = DF_REG_USE_CHAIN (regno);
+ for (insnR = NULL, ref = DF_REG_USE_CHAIN (regno);
ref; ref = DF_REF_NEXT_REG (ref))
if (DF_REF_CLASS (ref) != DF_REF_REGULAR
|| DEBUG_INSN_P (insn = DF_REF_INSN (ref)))
@@ -3664,12 +3663,7 @@ xtensa_can_eliminate_callee_saved_reg_p (unsigned int
regno,
else
return false;
- if (!insnS || !insnR)
- return false;
-
- *p_insnS = insnS, *p_insnR = insnR;
-
- return true;
+ return insnS && insnR;
}
/* minimum frame = reg save area (4 words) plus static chain (1 word)
@@ -3772,7 +3766,7 @@ xtensa_expand_prologue (void)
if (!large_stack_needed
&& xtensa_can_eliminate_callee_saved_reg_p (regno,
- &insnS, &insnR))
+ insnS, insnR))
{
if (frame_pointer_needed)
mem = replace_rtx (mem, stack_pointer_rtx,
--
2.39.5
