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nvptx: Handle '__builtin_stack_save()' in a well-behaved way for PTX "native" stacks [PR65181]

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PR target/65181
	gcc/
	* config/nvptx/nvptx.md [!TARGET_SOFT_STACK] (save_stack_block):
	'define_expand'.
	gcc/testsuite/
	* gcc.target/nvptx/__builtin_stack_save___builtin_stack_restore-1.c:
	Adjust.
This commit is contained in:
Thomas Schwinge 2024-12-13 15:09:49 +01:00
parent 2116e8d227
commit 1823170805
2 changed files with 23 additions and 12 deletions
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18
gcc/config/nvptx/nvptx.md
View file

@ -1687,12 +1687,28 @@
return nvptx_output_set_softstack (REGNO (operands[0]));
})
(define_expand "save_stack_block"
[(match_operand 0 "register_operand" "")
(match_operand 1 "register_operand" "")]
"!TARGET_SOFT_STACK"
{
/* The concept of a '%stack' pointer doesn't apply like this for
PTX "native" stacks. GCC however occasionally synthesizes
'__builtin_stack_save ()', '__builtin_stack_restore ()', and isn't able to
optimize them all away. Just submit a dummy -- user code shouldn't be
able to observe this. */
emit_move_insn (operands[0], GEN_INT (0xdeadbeef));
DONE;
})
(define_expand "restore_stack_block"
[(match_operand 0 "register_operand" "")
(match_operand 1 "register_operand" "")]
""
{
if (TARGET_SOFT_STACK)
if (!TARGET_SOFT_STACK)
; /* See 'save_stack_block'. */
else
{
emit_move_insn (operands[0], operands[1]);
emit_insn (gen_set_softstack (Pmode, operands[0]));

17
gcc/testsuite/gcc.target/nvptx/__builtin_stack_save___builtin_stack_restore-1.c
View file

@ -1,7 +1,6 @@
/* Document what we do for '__builtin_stack_save()', '__builtin_stack_restore()'. */
/* { dg-do compile }
TODO We can't 'assemble' this -- it's invalid PTX code. */
/* { dg-do assemble } */
/* { dg-options {-O3 -mno-soft-stack} } */
/* { dg-additional-options -save-temps } */
/* { dg-final { check-function-bodies {** } {} } } */
@ -10,8 +9,10 @@ void *p;
void f(void)
{
// 0xdeadbeef
p = __builtin_stack_save();
asm volatile ("" : : : "memory");
// no-op
__builtin_stack_restore(p);
asm volatile ("" : : : "memory");
}
@ -19,14 +20,8 @@ void f(void)
** f:
** \.visible \.func f
** {
** st\.global\.u64 \[p\], %stack;
** \.reg\.u64 (%r[0-9]+);
** mov\.u64 \1, 3735928559;
** st\.global\.u64 \[p\], \1;
** ret;
*/
/* The concept of a '%stack' pointer doesn't apply like this for
'-mno-soft-stack': PTX "native" stacks (TODO).
{ dg-final { scan-assembler-not {%stack} { xfail *-*-* } } } */
/* As these are an internal-use built-in function, we don't bother with
emitting proper error diagnostics. */