Hi!
On Tue, Apr 18, 2023 at 03:12:50PM +0200, Aldy Hernandez wrote:
> [I don't know why I keep poking at floats. I must really like the pain.
> Jakub, are you OK with this patch for trunk?]
>
> This is the range-op entry for sin/cos. It is meant to serve as an
> example of what we can do for glibc math functions. It is by no means
> exhaustive, just a stub to restrict the return range from sin/cos to
> [-1.0, 1.0] with appropriate smarts of NANs.
>
> As can be seen in the testcase, we see sin() as well as
> __builtin_sin() in the IL, and can resolve the resulting range
> accordingly.
>
> gcc/ChangeLog:
>
> * gimple-range-op.cc (class cfn_sincos): New.
> (gimple_range_op_handler::maybe_builtin_call): Add case for sin/cos.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/range-sincos.c: New test.
Here is an updated version of the patch on top of the
v2: Add targetm.libm_function_max_error
patch with all my comments incorporated into your patch (but still no
handling of sin/cos ranges shorter than 2*M_PI).
So far tested on the new testcase with
RUNTESTFLAGS='--target_board=unix\{,-frounding-math}
tree-ssa.exp=range-sincos.c'
where expectedly without -frounding-math it PASSes and with it fails
(as the hooks return 4ulps in that case for the boundaries).
Ok for trunk if it passes bootstrap/regtest?
I'll defer tweaks to frange_nextafter for ulps or whatever you want to do
with it.
2023-04-27 Aldy Hernandez <[email protected]>
Jakub Jelinek <[email protected]>
* value-range.h (frange_nextafter): Declare.
* gimple-range-op.cc (class cfn_sincos): New.
(op_cfn_sin, op_cfn_cos): New variables.
(gimple_range_op_handler::maybe_builtin_call): Handle
CASE_CFN_{SIN,COS}{,_FN}.
* gcc.dg/tree-ssa/range-sincos.c: New test.
--- gcc/value-range.h.jj 2023-04-27 10:17:46.504485376 +0200
+++ gcc/value-range.h 2023-04-27 12:07:09.891147869 +0200
@@ -1388,4 +1388,7 @@ frange::nan_signbit_p (bool &signbit) co
return true;
}
+void frange_nextafter (enum machine_mode, REAL_VALUE_TYPE &,
+ const REAL_VALUE_TYPE &);
+
#endif // GCC_VALUE_RANGE_H
--- gcc/gimple-range-op.cc.jj 2023-04-22 10:23:26.942812958 +0200
+++ gcc/gimple-range-op.cc 2023-04-27 11:57:09.865879982 +0200
@@ -400,6 +400,89 @@ public:
}
} op_cfn_copysign;
+class cfn_sincos : public range_operator_float
+{
+public:
+ using range_operator_float::fold_range;
+ using range_operator_float::op1_range;
+ cfn_sincos (combined_fn cfn) { m_cfn = cfn; }
+ virtual bool fold_range (frange &r, tree type,
+ const frange &lh, const frange &,
+ relation_trio) const final override
+ {
+ if (lh.undefined_p ())
+ return false;
+ if (lh.known_isnan () || lh.known_isinf ())
+ {
+ r.set_nan (type);
+ return true;
+ }
+ unsigned bulps = targetm.libm_function_max_error (m_cfn, TYPE_MODE (type),
+ true);
+ if (bulps == ~0U)
+ r.set_varying (type);
+ else if (bulps == 0)
+ r.set (type, dconstm1, dconst1);
+ else
+ {
+ REAL_VALUE_TYPE boundmin, boundmax;
+ boundmax = dconst1;
+ while (bulps--)
+ frange_nextafter (TYPE_MODE (type), boundmax, dconstinf);
+ real_arithmetic (&boundmin, NEGATE_EXPR, &boundmax, NULL);
+ r.set (type, boundmin, boundmax);
+ }
+ if (!lh.maybe_isnan () && !lh.maybe_isinf ())
+ r.clear_nan ();
+ return true;
+ }
+ virtual bool op1_range (frange &r, tree type,
+ const frange &lhs, const frange &,
+ relation_trio) const final override
+ {
+ if (lhs.undefined_p ())
+ return false;
+
+ // A known NAN means the input is [-INF,-INF][+INF,+INF] U +-NAN,
+ // which we can't currently represent.
+ if (lhs.known_isnan ())
+ {
+ r.set_varying (type);
+ return true;
+ }
+
+ // Results outside of [-1.0, +1.0] are impossible.
+ REAL_VALUE_TYPE lb = lhs.lower_bound ();
+ REAL_VALUE_TYPE ub = lhs.upper_bound ();
+ if (real_less (&ub, &dconstm1) || real_less (&dconst1, &lb))
+ {
+ if (!lhs.maybe_isnan ())
+ r.set_undefined ();
+ else
+ /* If lhs could be NAN and finite result is impossible,
+ the range is like lhs.known_isnan () above,
+ [-INF,-INF][+INF,+INF] U +-NAN. */
+ r.set_varying (type);
+ return true;
+ }
+
+ if (!lhs.maybe_isnan ())
+ {
+ // If NAN is not valid result, the input cannot include either
+ // a NAN nor a +-INF.
+ lb = real_min_representable (type);
+ ub = real_max_representable (type);
+ r.set (type, lb, ub, nan_state (false, false));
+ return true;
+ }
+
+ r.set_varying (type);
+ return true;
+ }
+private:
+ combined_fn m_cfn;
+} op_cfn_sin (CFN_SIN), op_cfn_cos (CFN_COS);
+
// Implement range operator for CFN_BUILT_IN_TOUPPER and CFN_BUILT_IN_TOLOWER.
class cfn_toupper_tolower : public range_operator
{
@@ -878,6 +961,20 @@ gimple_range_op_handler::maybe_builtin_c
m_valid = true;
break;
+ CASE_CFN_SIN:
+ CASE_CFN_SIN_FN:
+ m_op1 = gimple_call_arg (call, 0);
+ m_float = &op_cfn_sin;
+ m_valid = true;
+ break;
+
+ CASE_CFN_COS:
+ CASE_CFN_COS_FN:
+ m_op1 = gimple_call_arg (call, 0);
+ m_float = &op_cfn_cos;
+ m_valid = true;
+ break;
+
case CFN_BUILT_IN_TOUPPER:
case CFN_BUILT_IN_TOLOWER:
// Only proceed If the argument is compatible with the LHS.
--- gcc/testsuite/gcc.dg/tree-ssa/range-sincos.c.jj 2023-04-27
10:27:08.135348612 +0200
+++ gcc/testsuite/gcc.dg/tree-ssa/range-sincos.c 2023-04-27
12:14:50.788437504 +0200
@@ -0,0 +1,43 @@
+// { dg-do compile }
+// { dg-options "-O2 -fdump-tree-evrp -fno-thread-jumps" }
+
+#include <math.h>
+
+void use (double);
+void link_error ();
+
+void
+foo (double x)
+{
+ if (__builtin_isnan (x))
+ __builtin_unreachable ();
+ x = sin (x);
+ if (x < -1.0 || x > 1.0)
+ link_error ();
+ use (x);
+}
+
+void
+bar (double x)
+{
+ if (!__builtin_isnan (sin (x)))
+ {
+ if (__builtin_isnan (x))
+ link_error ();
+ if (__builtin_isinf (x))
+ link_error ();
+ }
+}
+
+void
+stool (double x)
+{
+ double res1 = sin (x);
+ double res2 = __builtin_sin (x);
+ if (res1 < -1.0 || res2 < -1.0)
+ link_error ();
+ if (res1 > 1.0 || res2 > 1.0)
+ link_error ();
+}
+
+// { dg-final { scan-tree-dump-not "link_error" "evrp" { target { { *-*-linux*
} && { glibc } } } } }
Jakub
