Viewing file:  ranger-threader-5.c (2.21 KB) -rw-r--r--
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// { dg-do compile }
// { dg-options "-fgimple -O2 -fdump-tree-thread1-details" }
/* This tests that we can thread BB4->BB999 coming in through the
following path:
latch many insns
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V V
6 -> 7 -> 3 -> 4 -> 999
The ranger based threader cannot thread this because BB4 has too
many instructions so it gives up looking back. However, if we were
able to looking further, we would notice that a profitable path
passing through the loop latch (BB7) exists.
That is, 3->4->N in isolation is not profitable, but 6->7->3->4->N is.
It is not clear whether handling this case in the backwards
threader is profitable, as it would increase the search space
considerably. The test is being added to note a regression from
the old backward threader code.
This test has been distilled from libphobos/src/std/net/isemail.d.
The ranger threader stops at the 3->4 subpath with: "did not thread
around loop and would copy too many statements". */
extern void bar();
extern int random();
int __GIMPLE (ssa,startwith("thread1"))
foo (int key)
{
int context;
int _1454;
__BB(2):
goto __BB3;
// Loop header.
__BB(3):
context_448 = __PHI (__BB2: 0, __BB7: context_450);
if (key_5(D) > 0)
goto __BB999;
else
goto __BB4;
__BB(4):
bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar();
bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar();
bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar();
bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar();
bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar();
bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar(); bar();
switch (context_448) {default: L5; case 0: L999; }
__BB(5):
L5:
goto __BB6;
__BB(6):
context_450 = __PHI (__BB5: 0);
_1454 = random ();
if (_1454 > 0)
goto __BB999;
else
goto __BB7;
// Loop latch.
__BB(7):
goto __BB3;
__BB(999):
L999:
return 5;
}
// { dg-final { scan-tree-dump-times "Registering.*jump thread.*incoming edge; \\(6, 7\\) \\(7, 3\\) \\(3, 4\\) \\(4, 999\\) nocopy" 1 "thread1" { xfail *-*-* } } }
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