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finite_loop_p tweak

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We have finite_p flag in loop structure.  finite_loop_p already know to
use it, but we also may set the flag when we prove loop to be finite by
SCEV analysis to avoid duplicated work.

Bootstrapped/regtested x86_64-linux, OK?

gcc/ChangeLog:

	* tree-ssa-loop-niter.cc (finite_loop_p): Reorder to do cheap
	tests first; update finite_p flag.
This commit is contained in:
Jan Hubicka 2023-07-21 13:57:34 +02:00
parent 15ec8d5ab5
commit 3038d59852
1 changed files with 26 additions and 19 deletions
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45
gcc/tree-ssa-loop-niter.cc
View file

@ -3338,24 +3338,6 @@ finite_loop_p (class loop *loop)
widest_int nit;
int flags;
flags = flags_from_decl_or_type (current_function_decl);
if ((flags & (ECF_CONST|ECF_PURE)) && !(flags & ECF_LOOPING_CONST_OR_PURE))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found loop %i to be finite: it is within pure or const function.\n",
loop->num);
return true;
}
if (loop->any_upper_bound
|| max_loop_iterations (loop, &nit))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found loop %i to be finite: upper bound found.\n",
loop->num);
return true;
}
if (loop->finite_p)
{
unsigned i;
@ -3368,11 +3350,36 @@ finite_loop_p (class loop *loop)
{
if (dump_file)
fprintf (dump_file, "Assume loop %i to be finite: it has an exit "
"and -ffinite-loops is on.\n", loop->num);
"and -ffinite-loops is on or loop was "
"previously finite.\n",
loop->num);
return true;
}
}
flags = flags_from_decl_or_type (current_function_decl);
if ((flags & (ECF_CONST|ECF_PURE)) && !(flags & ECF_LOOPING_CONST_OR_PURE))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file,
"Found loop %i to be finite: it is within "
"pure or const function.\n",
loop->num);
loop->finite_p = true;
return true;
}
if (loop->any_upper_bound
/* Loop with no normal exit will not pass max_loop_iterations. */
|| (!loop->finite_p && max_loop_iterations (loop, &nit)))
{
if (dump_file && (dump_flags & TDF_DETAILS))
fprintf (dump_file, "Found loop %i to be finite: upper bound found.\n",
loop->num);
loop->finite_p = true;
return true;
}
return false;
}