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| author | Jakub Jelinek <jakub@redhat.com> | 2014-09-24 11:14:17 +0200 |
|---|---|---|
| committer | Jakub Jelinek <jakub@gcc.gnu.org> | 2014-09-24 11:14:17 +0200 |
| commit | acf816a3aca64e21ba98cedff112919313fdf6ce (patch) | |
| tree | 746bddba6f5c3ef46034c2673ec3a1f5543519bd /gcc/asan.c | |
| parent | aa29ea0cd4054b64d9dbc9adba3bfd2db2a86be1 (diff) | |
| download | gcc-acf816a3aca64e21ba98cedff112919313fdf6ce.zip gcc-acf816a3aca64e21ba98cedff112919313fdf6ce.tar.gz gcc-acf816a3aca64e21ba98cedff112919313fdf6ce.tar.bz2 | |
re PR sanitizer/63316 (False asan positive)
PR sanitizer/63316
* asan.c (asan_expand_check_ifn): Fix up align >= 8 optimization.
* c-c++-common/asan/pr63316.c: New test.
From-SVN: r215547
Diffstat (limited to 'gcc/asan.c')
| -rw-r--r-- | gcc/asan.c | 29 |
1 files changed, 18 insertions, 11 deletions
@@ -2585,19 +2585,26 @@ asan_expand_check_ifn (gimple_stmt_iterator *iter, bool use_calls) gimple shadow_test = build_assign (NE_EXPR, shadow, 0); gimple_seq seq = NULL; gimple_seq_add_stmt (&seq, shadow_test); - /* Aligned (>= 8 bytes) access do not need & 7. */ + /* Aligned (>= 8 bytes) can test just + (real_size_in_bytes - 1 >= shadow), as base_addr & 7 is known + to be 0. */ if (align < 8) - gimple_seq_add_stmt (&seq, build_assign (BIT_AND_EXPR, - base_addr, 7)); - gimple_seq_add_stmt (&seq, build_type_cast (shadow_type, - gimple_seq_last (seq))); - if (real_size_in_bytes > 1) - gimple_seq_add_stmt (&seq, - build_assign (PLUS_EXPR, gimple_seq_last (seq), - real_size_in_bytes - 1)); - gimple_seq_add_stmt (&seq, build_assign (GE_EXPR, + { + gimple_seq_add_stmt (&seq, build_assign (BIT_AND_EXPR, + base_addr, 7)); + gimple_seq_add_stmt (&seq, + build_type_cast (shadow_type, + gimple_seq_last (seq))); + if (real_size_in_bytes > 1) + gimple_seq_add_stmt (&seq, + build_assign (PLUS_EXPR, gimple_seq_last (seq), - shadow)); + real_size_in_bytes - 1)); + t = gimple_assign_lhs (gimple_seq_last_stmt (seq)); + } + else + t = build_int_cst (shadow_type, real_size_in_bytes - 1); + gimple_seq_add_stmt (&seq, build_assign (GE_EXPR, t, shadow)); gimple_seq_add_stmt (&seq, build_assign (BIT_AND_EXPR, shadow_test, gimple_seq_last (seq))); t = gimple_assign_lhs (gimple_seq_last (seq)); |