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nvptx: Add '__builtin_alloca(0)' test cases [PR65181]

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Documenting the status quo.  This specific behavior relates to a 1994 change
(Subversion r7229, Git commit 15fc002672).
That one, however, isn't to blame here: we'd otherwise of course run into
nvptx' 'sorry, unimplemented: target cannot support alloca'.

	PR target/65181
	gcc/testsuite/
	* gcc.target/nvptx/__builtin_alloca_0-1-O0.c: New.
	* gcc.target/nvptx/__builtin_alloca_0-1-O1.c: Likewise.
This commit is contained in:
Thomas Schwinge 2024-12-12 23:26:14 +01:00
parent 36eee5a74e
commit 678c3f06fc
2 changed files with 70 additions and 0 deletions
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37
gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O0.c Normal file
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/* Document what we run into for '__builtin_alloca(0)'. */
/* { dg-do compile }
TODO We can't 'assemble' this -- it's invalid PTX code. */
/* { dg-options {-O0 -mno-soft-stack} } */
/* { dg-additional-options -save-temps } */
/* { dg-final { check-function-bodies {** } {} } } */
void sink(void *);
void f(void)
{
sink(__builtin_alloca(0));
}
/*
** f:
** .visible .func f
** {
** \.reg\.u64 (%r[0-9]+);
** \.reg\.u64 (%r[0-9]+);
** mov\.u64 \1, %stack;
** mov\.u64 \2, \1;
** {
** \.param\.u64 %out_arg1;
** st\.param\.u64 \[%out_arg1\], \2;
** call sink, \(%out_arg1\);
** }
** ret;
*/
/* '%stack' is 'VIRTUAL_STACK_DYNAMIC_REGNUM', 'virtual_stack_dynamic_rtx'.
For '__builtin_alloca (0)', we get to
'gcc/explow.cc:allocate_dynamic_stack_space', where 'addr' gets set to
'virtual_stack_dynamic_rtx', 'size == const0_rtx', therefore 'return addr;',
which gets us '%stack' -- undefined (TODO).
{ dg-final { scan-assembler-not {%stack} { xfail *-*-* } } } */

33
gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O1.c Normal file
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/* Document what we run into for '__builtin_alloca(0)'. */
/* { dg-do compile }
TODO We can't 'assemble' this -- it's invalid PTX code. */
/* { dg-options {-O1 -mno-soft-stack} } */
/* { dg-additional-options -save-temps } */
/* { dg-final { check-function-bodies {** } {} } } */
void sink(void *);
void f(void)
{
sink(__builtin_alloca(0));
}
/*
** f:
** .visible .func f
** {
** {
** \.param\.u64 %out_arg1;
** st\.param\.u64 \[%out_arg1\], %stack;
** call sink, \(%out_arg1\);
** }
** ret;
*/
/* '%stack' is 'VIRTUAL_STACK_DYNAMIC_REGNUM', 'virtual_stack_dynamic_rtx'.
For '__builtin_alloca (0)', we get to
'gcc/explow.cc:allocate_dynamic_stack_space', where 'addr' gets set to
'virtual_stack_dynamic_rtx', 'size == const0_rtx', therefore 'return addr;',
which gets us '%stack' -- undefined (TODO).
{ dg-final { scan-assembler-not {%stack} { xfail *-*-* } } } */