From c3e686a350915a66b0761fa825fc162ef0010c3e Mon Sep 17 00:00:00 2001 From: Eric Botcazou Date: Thu, 5 Jan 2012 22:21:29 +0000 Subject: [PATCH] re PR tree-optimization/51315 (unaligned memory accesses generated with -ftree-sra) PR tree-optimization/51315 * tree-sra.c (tree_non_aligned_mem_for_access_p): New predicate. (build_accesses_from_assign): Use it instead of tree_non_aligned_mem_p. From-SVN: r182932 --- gcc/ChangeLog | 6 +++++ gcc/testsuite/ChangeLog | 5 ++++ .../gcc.c-torture/execute/20120105-1.c | 24 ++++++++++++++++++ gcc/tree-sra.c | 25 ++++++++++++++++--- 4 files changed, 56 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.c-torture/execute/20120105-1.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 206e9ceb4934..9d2648d8dea3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2012-01-05 Eric Botcazou + + PR tree-optimization/51315 + * tree-sra.c (tree_non_aligned_mem_for_access_p): New predicate. + (build_accesses_from_assign): Use it instead of tree_non_aligned_mem_p. + 2012-01-05 Uros Bizjak PR target/51681 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 3821d7c3be6d..5fdcd1189d39 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ + +2012-01-05 Eric Botcazou + + * gcc.c-torture/execute/20120104-1.c: New test. + 2012-01-05 Paul Thomas PR fortran/PR48946 diff --git a/gcc/testsuite/gcc.c-torture/execute/20120105-1.c b/gcc/testsuite/gcc.c-torture/execute/20120105-1.c new file mode 100644 index 000000000000..115ba1509d49 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/20120105-1.c @@ -0,0 +1,24 @@ +struct __attribute__((packed)) S +{ + int a, b, c; +}; + +static int __attribute__ ((noinline,noclone)) +extract(const char *p) +{ + struct S s; + __builtin_memcpy (&s, p, sizeof(struct S)); + return s.a; +} + +volatile int i; + +int main (void) +{ + char p[sizeof(struct S) + 1]; + + __builtin_memset (p, 0, sizeof(struct S) + 1); + i = extract (p + 1); + + return 0; +} diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c index accbc1ebaf4a..600f4d776d1a 100644 --- a/gcc/tree-sra.c +++ b/gcc/tree-sra.c @@ -1095,6 +1095,25 @@ tree_non_aligned_mem_p (tree exp, unsigned int align) return false; } +/* Return true if EXP is a memory reference less aligned than what the access + ACC would require. This is invoked only on strict-alignment targets. */ + +static bool +tree_non_aligned_mem_for_access_p (tree exp, struct access *acc) +{ + unsigned int acc_align; + + /* The alignment of the access is that of its expression. However, it may + have been artificially increased, e.g. by a local alignment promotion, + so we cap it to the alignment of the type of the base, on the grounds + that valid sub-accesses cannot be more aligned than that. */ + acc_align = get_object_alignment (acc->expr); + if (acc->base && acc_align > TYPE_ALIGN (TREE_TYPE (acc->base))) + acc_align = TYPE_ALIGN (TREE_TYPE (acc->base)); + + return tree_non_aligned_mem_p (exp, acc_align); +} + /* Scan expressions occuring in STMT, create access structures for all accesses to candidates for scalarization and remove those candidates which occur in statements or expressions that prevent them from being split apart. Return @@ -1123,8 +1142,7 @@ build_accesses_from_assign (gimple stmt) if (lacc) { lacc->grp_assignment_write = 1; - if (STRICT_ALIGNMENT - && tree_non_aligned_mem_p (rhs, get_object_alignment (lhs))) + if (STRICT_ALIGNMENT && tree_non_aligned_mem_for_access_p (rhs, lacc)) lacc->grp_unscalarizable_region = 1; } @@ -1134,8 +1152,7 @@ build_accesses_from_assign (gimple stmt) if (should_scalarize_away_bitmap && !gimple_has_volatile_ops (stmt) && !is_gimple_reg_type (racc->type)) bitmap_set_bit (should_scalarize_away_bitmap, DECL_UID (racc->base)); - if (STRICT_ALIGNMENT - && tree_non_aligned_mem_p (lhs, get_object_alignment (rhs))) + if (STRICT_ALIGNMENT && tree_non_aligned_mem_for_access_p (lhs, racc)) racc->grp_unscalarizable_region = 1; }