On Thu, Jul 9, 2015 at 4:04 AM, Uros Bizjak <ubiz...@gmail.com> wrote:
> On Thu, Jul 9, 2015 at 12:54 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
>> Indirect sibcall with register arguments is OK when there is register
>> available for argument passing.
>>
>> OK for trunk if there is no regression?
>>
>>
>> H.J.
>> ---
>> gcc/
>>
>> PR target/66819
>> * config/i386/i386.c (ix86_function_ok_for_sibcall): Allow
>> indirect sibcall with register arguments if register available
>> for argument passing.
>> (init_cumulative_args): Set cfun->machine->arg_reg_available_p
>> to cum->nregs != 0.
>> (function_arg_advance_32): Set cfun->machine->arg_reg_available_p
>> to 0 when setting cum->nregs = 0.
>> * config/i386/i386.h (machine_function): Add arg_reg_available_p.
>>
>> gcc/testsuite/
>>
>> PR target/66819
>> * gcc.target/i386/pr66819-1.c: New test.
>> * gcc.target/i386/pr66819-2.c: Likewise.
>> * gcc.target/i386/pr66819-3.c: Likewise.
>> * gcc.target/i386/pr66819-4.c: Likewise.
>> * gcc.target/i386/pr66819-5.c: Likewise.
>> ---
>> gcc/config/i386/i386.c | 15 +++++++++------
>> gcc/config/i386/i386.h | 3 +++
>> gcc/testsuite/gcc.target/i386/pr66819-1.c | 8 ++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-2.c | 8 ++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-3.c | 10 ++++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-4.c | 12 ++++++++++++
>> gcc/testsuite/gcc.target/i386/pr66819-5.c | 10 ++++++++++
>> 7 files changed, 60 insertions(+), 6 deletions(-)
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-1.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-2.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-3.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-4.c
>> create mode 100644 gcc/testsuite/gcc.target/i386/pr66819-5.c
>>
>> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>> index 54ee6f3..85e59a8 100644
>> --- a/gcc/config/i386/i386.c
>> +++ b/gcc/config/i386/i386.c
>> @@ -5628,12 +5628,12 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
>> if (!decl
>> || (TARGET_DLLIMPORT_DECL_ATTRIBUTES && DECL_DLLIMPORT_P (decl)))
>> {
>> - if (ix86_function_regparm (type, NULL) >= 3)
>> - {
>> - /* ??? Need to count the actual number of registers to be used,
>> - not the possible number of registers. Fix later. */
>> - return false;
>> - }
>> + /* FIXME: The symbol indirect call doesn't need a
>> + call-clobbered register. But we don't know if
>> + this is a symbol indirect call or not here. */
>> + if (ix86_function_regparm (type, NULL) >= 3
>> + && !cfun->machine->arg_reg_available_p)
>> + return false;
>> }
>> }
>
> Why can't we directly look at nregs != 0 in the above code? AFAICS,
> nregs accurately tracks number of available argument registers.
>
I tried it first. But nregs isn't accessible from ix86_function_ok_for_sibcall.
--
H.J.
