On Tue, Sep 6, 2022 at 9:59 AM Jakub Jelinek <[email protected]> wrote: > > On Tue, Sep 06, 2022 at 09:49:55AM +0200, Aldy Hernandez wrote: > > On Tue, Sep 6, 2022 at 9:44 AM Jakub Jelinek <[email protected]> wrote: > > > > > > On Tue, Sep 06, 2022 at 09:40:59AM +0200, Aldy Hernandez wrote: > > > > if (x <= Inf) > > > > > > This will be [-Inf, Inf] !NAN on the true side and > > > NAN (either sign) on the false side indeed. > > > > > > > if (x < -Inf) > > > > > > will be NAN (either sign) on the true side and > > > [-Inf, Inf] !NAN on the false side. > > > > Sweet, that's exactly what I thought, thus the patch. > > > > Furthermore, for !HONOR_NANS I would expect the NAN sides above to be > > UNDEFINED/unreachable. That is, the false side of x <= Inf when > > !HONOR_NANS is unreachable. > > In practice, there is no real format that has NaNs and doesn't have Infs > or vice versa and similarly we have just one switch to cover both Infinities > and NaNs, so either both are supported, or neither of them, or both > are supported but neither of them should appear in a valid program > (-ffinite-math-only on most floating point formats). > So the answer in that case is a little bit fuzzy because one shouldn't > compare against infinity in that case (or for !MODE_HAS_INFINITIES even > can't). But sure, if NaNs aren't possible or can't appear and you compare > x <= Largest_possible_float, then it is always true and so UNDEFINED on the > false edge.
OK, let's leave it as undefined to be consistent. Come to think of it, perhaps we could represent the endpoints (varying, [x, +INF], etc) as the min/max representable values for the type (for !HONOR_NANS). I don't think it would make a big difference, but we might get better results for some corner cases. Question...for !HONOR_NANS or !HONOR_INFINITIES or whatever, say the range for the domain is [-MIN, +MAX] for the min and max representable numbers. What happens for MAX+1? Is that undefined? I wonder what real.cc does for that. Attached is the final version of the patch I'm pushing. Tested (+mpfr tests) on x86-64 Linux. Aldy
From fd52ffb9997becafa31c5109b50fe274da12aed8 Mon Sep 17 00:00:00 2001 From: Aldy Hernandez <[email protected]> Date: Tue, 6 Sep 2022 08:20:54 +0200 Subject: [PATCH] Handle > INF and < INF correctly in range-op-float.cc The gfortran.dg/minlocval*.f90 tests are generating conditionals past the infinities. For example: if (x <= +Inf) foo (x); else bar (x); It seems to me that the only possible value for x on the false side is either NAN or undefined (for !HONOR_NANS). gcc/ChangeLog: * range-op-float.cc (build_le): Handle NANs and going past infinity. (build_lt): Same. (build_ge): Same. (build_gt): Same. (foperator_lt::op1_range): Avoid adjustments to range if build_* returned false. (foperator_lt::op2_range): Same. (foperator_le::op1_range): Same. (foperator_le::op2_range): Same. (foperator_gt::op1_range): Same. (foperator_gt::op2_range): Same. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/vrp-float-inf-1.c: New test. --- gcc/range-op-float.cc | 99 ++++++++++++++----- .../gcc.dg/tree-ssa/vrp-float-inf-1.c | 15 +++ 2 files changed, 90 insertions(+), 24 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc index 050f07a9867..5fbbaa1fb36 100644 --- a/gcc/range-op-float.cc +++ b/gcc/range-op-float.cc @@ -224,36 +224,79 @@ frange_drop_ninf (frange &r, tree type) // (X <= VAL) produces the range of [-INF, VAL]. -static void +static bool build_le (frange &r, tree type, const REAL_VALUE_TYPE &val) { + if (real_isnan (&val)) + { + r.set_undefined (); + return false; + } r.set (type, dconstninf, val); + return true; } // (X < VAL) produces the range of [-INF, VAL). -static void +static bool build_lt (frange &r, tree type, const REAL_VALUE_TYPE &val) { + if (real_isnan (&val)) + { + r.set_undefined (); + return false; + } + // < -INF is outside the range. + if (real_isinf (&val, 1)) + { + if (HONOR_NANS (type)) + frange_set_nan (r, type); + else + r.set_undefined (); + return false; + } // Hijack LE because we only support closed intervals. build_le (r, type, val); + return true; } // (X >= VAL) produces the range of [VAL, +INF]. -static void +static bool build_ge (frange &r, tree type, const REAL_VALUE_TYPE &val) { + if (real_isnan (&val)) + { + r.set_undefined (); + return false; + } r.set (type, val, dconstinf); + return true; } // (X > VAL) produces the range of (VAL, +INF]. -static void +static bool build_gt (frange &r, tree type, const REAL_VALUE_TYPE &val) { + if (real_isnan (&val)) + { + r.set_undefined (); + return false; + } + // > +INF is outside the range. + if (real_isinf (&val, 0)) + { + if (HONOR_NANS (type)) + frange_set_nan (r, type); + else + r.set_undefined (); + return false; + } + // Hijack GE because we only support closed intervals. build_ge (r, type, val); + return true; } @@ -520,10 +563,12 @@ foperator_lt::op1_range (frange &r, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - build_lt (r, type, op2.upper_bound ()); - r.set_nan (fp_prop::NO); - // x < y implies x is not +INF. - frange_drop_inf (r, type); + if (build_lt (r, type, op2.upper_bound ())) + { + r.set_nan (fp_prop::NO); + // x < y implies x is not +INF. + frange_drop_inf (r, type); + } break; case BRS_FALSE: @@ -546,10 +591,12 @@ foperator_lt::op2_range (frange &r, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - build_gt (r, type, op1.lower_bound ()); - r.set_nan (fp_prop::NO); - // x < y implies y is not -INF. - frange_drop_ninf (r, type); + if (build_gt (r, type, op1.lower_bound ())) + { + r.set_nan (fp_prop::NO); + // x < y implies y is not -INF. + frange_drop_ninf (r, type); + } break; case BRS_FALSE: @@ -618,8 +665,8 @@ foperator_le::op1_range (frange &r, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - build_le (r, type, op2.upper_bound ()); - r.set_nan (fp_prop::NO); + if (build_le (r, type, op2.upper_bound ())) + r.set_nan (fp_prop::NO); break; case BRS_FALSE: @@ -642,8 +689,8 @@ foperator_le::op2_range (frange &r, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - build_ge (r, type, op1.lower_bound ()); - r.set_nan (fp_prop::NO); + if (build_ge (r, type, op1.lower_bound ())) + r.set_nan (fp_prop::NO); break; case BRS_FALSE: @@ -712,10 +759,12 @@ foperator_gt::op1_range (frange &r, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - build_gt (r, type, op2.lower_bound ()); - r.set_nan (fp_prop::NO); - // x > y implies x is not -INF. - frange_drop_ninf (r, type); + if (build_gt (r, type, op2.lower_bound ())) + { + r.set_nan (fp_prop::NO); + // x > y implies x is not -INF. + frange_drop_ninf (r, type); + } break; case BRS_FALSE: @@ -738,10 +787,12 @@ foperator_gt::op2_range (frange &r, switch (get_bool_state (r, lhs, type)) { case BRS_TRUE: - build_lt (r, type, op1.upper_bound ()); - r.set_nan (fp_prop::NO); - // x > y implies y is not +INF. - frange_drop_inf (r, type); + if (build_lt (r, type, op1.upper_bound ())) + { + r.set_nan (fp_prop::NO); + // x > y implies y is not +INF. + frange_drop_inf (r, type); + } break; case BRS_FALSE: diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c new file mode 100644 index 00000000000..1d21cce41e6 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp-float-inf-1.c @@ -0,0 +1,15 @@ +// { dg-do compile } +// { dg-options "-O2 -fdump-tree-evrp-details" } + +void foo (); +void bar (double); + +void funky(double f, double g) +{ + if (f <= __builtin_inf ()) + foo (); + else + bar (f); +} + +// { dg-final { scan-tree-dump-not " Inf, Inf" "evrp" } } -- 2.37.1
