public inbox for gcc-cvs@sourceware.org help / color / mirror / Atom feed
From: Jakub Jelinek <jakub@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-5397] frange: Fix up foperator_{, not_}equal::fold_range for signed zeros [PR108540] Date: Thu, 26 Jan 2023 16:28:32 +0000 (GMT) [thread overview] Message-ID: <20230126162832.C3CDE3858C83@sourceware.org> (raw) https://gcc.gnu.org/g:09176201ec6a21c25b1edb07f19f83be22a123f9 commit r13-5397-g09176201ec6a21c25b1edb07f19f83be22a123f9 Author: Jakub Jelinek <jakub@redhat.com> Date: Thu Jan 26 17:21:22 2023 +0100 frange: Fix up foperator_{,not_}equal::fold_range for signed zeros [PR108540] The following testcases are miscompiled, because threader sees some SSA_NAME would have -0.0 value and when computing range of SSA_NAME == 0.0 foperator_equal::fold_range sees one operand has [-0.0, -0.0] singleton range, the other [0.0, 0.0], they aren't equal (frange operator== uses real_identical etc. rather than real comparisons) and so it thinks they compare unequal. With signed zeros -0.0 == 0.0 is true though, so we need to special case the both ranges singleton code. Similarly, if we see op1 range being say [-42.0, -0.0] and op2 range [0.0, 42.0], we'd check that the intersection of the two ranges is empty (that is correct) and fold the result of == between such operands to [0, 0] which is wrong, because -0.0 == 0.0, it needs to be [0, 1]. Similarly for foperator_not_equal::fold_range. 2023-01-26 Jakub Jelinek <jakub@redhat.com> PR tree-optimization/108540 * range-op-float.cc (foperator_equal::fold_range): If both op1 and op2 are singletons, use range_true even if op1 != op2 when one range is [-0.0, -0.0] and another [0.0, 0.0]. Similarly, even if intersection of the ranges is empty and one has zero low bound and another zero high bound, use range_true_and_false rather than range_false. (foperator_not_equal::fold_range): If both op1 and op2 are singletons, use range_false even if op1 != op2 when one range is [-0.0, -0.0] and another [0.0, 0.0]. Similarly, even if intersection of the ranges is empty and one has zero low bound and another zero high bound, use range_true_and_false rather than range_true. * gcc.c-torture/execute/ieee/pr108540-1.c: New test. * gcc.c-torture/execute/ieee/pr108540-2.c: New test. Diff: --- gcc/range-op-float.cc | 40 +++++++++-- .../gcc.c-torture/execute/ieee/pr108540-1.c | 84 ++++++++++++++++++++++ .../gcc.c-torture/execute/ieee/pr108540-2.c | 23 ++++++ 3 files changed, 142 insertions(+), 5 deletions(-) diff --git a/gcc/range-op-float.cc b/gcc/range-op-float.cc index 74ac4658378..2db83aeb2fc 100644 --- a/gcc/range-op-float.cc +++ b/gcc/range-op-float.cc @@ -607,6 +607,10 @@ foperator_equal::fold_range (irange &r, tree type, { if (op1 == op2) r = range_true (type); + // If one operand is -0.0 and other 0.0, they are still equal. + else if (real_iszero (&op1.lower_bound ()) + && real_iszero (&op2.lower_bound ())) + r = range_true (type); else r = range_false (type); } @@ -617,7 +621,18 @@ foperator_equal::fold_range (irange &r, tree type, frange tmp = op1; tmp.intersect (op2); if (tmp.undefined_p ()) - r = range_false (type); + { + // If one range is [whatever, -0.0] and another + // [0.0, whatever2], we don't know anything either, + // because -0.0 == 0.0. + if ((real_iszero (&op1.upper_bound ()) + && real_iszero (&op2.lower_bound ())) + || (real_iszero (&op1.lower_bound ()) + && real_iszero (&op2.upper_bound ()))) + r = range_true_and_false (type); + else + r = range_false (type); + } else r = range_true_and_false (type); } @@ -708,10 +723,14 @@ foperator_not_equal::fold_range (irange &r, tree type, // consist of a single value, and then compare them. else if (op1.singleton_p () && op2.singleton_p ()) { - if (op1 != op2) - r = range_true (type); - else + if (op1 == op2) r = range_false (type); + // If one operand is -0.0 and other 0.0, they are still equal. + else if (real_iszero (&op1.lower_bound ()) + && real_iszero (&op2.lower_bound ())) + r = range_false (type); + else + r = range_true (type); } else if (!maybe_isnan (op1, op2)) { @@ -720,7 +739,18 @@ foperator_not_equal::fold_range (irange &r, tree type, frange tmp = op1; tmp.intersect (op2); if (tmp.undefined_p ()) - r = range_true (type); + { + // If one range is [whatever, -0.0] and another + // [0.0, whatever2], we don't know anything either, + // because -0.0 == 0.0. + if ((real_iszero (&op1.upper_bound ()) + && real_iszero (&op2.lower_bound ())) + || (real_iszero (&op1.lower_bound ()) + && real_iszero (&op2.upper_bound ()))) + r = range_true_and_false (type); + else + r = range_true (type); + } else r = range_true_and_false (type); } diff --git a/gcc/testsuite/gcc.c-torture/execute/ieee/pr108540-1.c b/gcc/testsuite/gcc.c-torture/execute/ieee/pr108540-1.c new file mode 100644 index 00000000000..ebd4c502ee5 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/ieee/pr108540-1.c @@ -0,0 +1,84 @@ +/* PR tree-optimization/108540 */ + +__attribute__((noipa)) void +bar (const char *cp, unsigned long size, char sign, int dsgn) +{ + if (__builtin_strcmp (cp, "ZERO") != 0 || size != 4 || sign != '-' || dsgn != 1) + __builtin_abort (); +} + +__attribute__((noipa)) void +foo (int x, int ch, double d) +{ + const char *cp = ""; + unsigned long size = 0; + char sign = '\0'; + switch (x) + { + case 42: + if (__builtin_isinf (d)) + { + if (d < 0) + sign = '-'; + cp = "Inf"; + size = 3; + break; + } + if (__builtin_isnan (d)) + { + cp = "NaN"; + size = 3; + break; + } + if (d < 0) + { + d = -d; + sign = '-'; + } + else if (d == 0.0 && __builtin_signbit (d)) + sign = '-'; + else + sign = '\0'; + if (ch == 'a' || ch == 'A') + { + union U { long long l; double d; } u; + int dsgn; + u.d = d; + if (u.l < 0) + { + dsgn = 1; + u.l &= 0x7fffffffffffffffLL; + } + else + dsgn = 0; + if (__builtin_isinf (d)) + { + cp = "INF"; + size = 3; + } + else if (__builtin_isnan (d)) + { + cp = "NAN"; + size = 3; + } + else if (d == 0) + { + cp = "ZERO"; + size = 4; + } + else + { + cp = "WRONG"; + size = 5; + } + bar (cp, size, sign, dsgn); + } + } +} + +int +main () +{ + foo (42, 'a', -0.0); + return 0; +} diff --git a/gcc/testsuite/gcc.c-torture/execute/ieee/pr108540-2.c b/gcc/testsuite/gcc.c-torture/execute/ieee/pr108540-2.c new file mode 100644 index 00000000000..f1b13c9060a --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/ieee/pr108540-2.c @@ -0,0 +1,23 @@ +/* PR tree-optimization/108540 */ + +__attribute__((noipa)) int +foo (int x, double d) +{ + if (x == 42) + d = -0.0; + if (d == 0.0) + return 42; + return 12; +} + +int +main () +{ + if (foo (42, 5.0) != 42 + || foo (42, 0.0) != 42 + || foo (42, -0.0) != 42 + || foo (10, 5.0) != 12 + || foo (10, 0.0) != 42 + || foo (10, -0.0) != 42) + __builtin_abort (); +}
reply other threads:[~2023-01-26 16:28 UTC|newest] Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20230126162832.C3CDE3858C83@sourceware.org \ --to=jakub@gcc.gnu.org \ --cc=gcc-cvs@gcc.gnu.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).