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From: Alexandre Oliva <aoliva@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/aoliva/heads/testme)] harden-conditionals: detach values before compares Date: Thu, 8 Jun 2023 10:42:22 +0000 (GMT) [thread overview] Message-ID: <20230608104222.9053A385700D@sourceware.org> (raw) https://gcc.gnu.org/g:848936fda2abec8bb78a4b96d1437990421fcae5 commit 848936fda2abec8bb78a4b96d1437990421fcae5 Author: Alexandre Oliva <oliva@adacore.com> Date: Thu Apr 27 02:43:48 2023 -0300 harden-conditionals: detach values before compares The optimization barriers inserted after compares enable GCC to derive information about the values from e.g. the taken paths, or the absence of exceptions. Move them before the original compares, so that the reversed compares test copies of the original operands, without further optimizations. for gcc/ChangeLog * gimple-harden-conditionals.cc (insert_edge_check_and_trap): Move detach value calls... (pass_harden_conditional_branches::execute): ... here. (pass_harden_compares::execute): Detach values before compares. for gcc/testsuite/ChangeLog * c-c++-common/torture/harden-cond-comp.c: New. Diff: --- gcc/testsuite/c-c++-common/torture/harden-cond-comp.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/gcc/testsuite/c-c++-common/torture/harden-cond-comp.c b/gcc/testsuite/c-c++-common/torture/harden-cond-comp.c index dcf364ee993..5aad890a1d3 100644 --- a/gcc/testsuite/c-c++-common/torture/harden-cond-comp.c +++ b/gcc/testsuite/c-c++-common/torture/harden-cond-comp.c @@ -1,11 +1,11 @@ /* { dg-do compile } */ /* { dg-options "-fharden-conditional-branches -fharden-compares -fdump-tree-hardcbr -fdump-tree-hardcmp -ffat-lto-objects" } */ -int f(int i, int j, int k, int l) { +int f(int i, int j) { if (i == 0) - return (j != 0) + l; + return j != 0; else - return (i * j != 0) * k; + return i * j != 0; } /* { dg-final { scan-tree-dump-times "Splitting edge" 2 "hardcbr" } } */
next reply other threads:[~2023-06-08 10:42 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-06-08 10:42 Alexandre Oliva [this message] -- strict thread matches above, loose matches on Subject: below -- 2023-06-09 6:16 Alexandre Oliva 2023-04-27 7:07 Alexandre Oliva 2023-04-27 5:59 Alexandre Oliva
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