diff options
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/builtins.c | 50 | ||||
| -rw-r--r-- | gcc/tree.h | 1 |
3 files changed, 43 insertions, 14 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index fd5acdb..d252a5a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2012-01-25 Richard Guenther <rguenther@suse.de> + + * tree.h (get_pointer_alignment_1): Declare. + * builtins.c (get_pointer_alignment_1): New function. + (get_pointer_alignment): Use it. + 2012-01-25 Ramana Radhakrishnan <ramana.radhakrishnan@linaro.org> PR rtl-optimization/48308 diff --git a/gcc/builtins.c b/gcc/builtins.c index 44b8551..d62b419 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -477,37 +477,59 @@ get_object_or_type_alignment (tree exp) return align; } -/* Return the alignment in bits of EXP, a pointer valued expression. - The alignment returned is, by default, the alignment of the thing that - EXP points to. If it is not a POINTER_TYPE, 0 is returned. +/* For a pointer valued expression EXP compute values M and N such that + M divides (EXP - N) and such that N < M. Store N in *BITPOSP and return M. - Otherwise, look at the expression to see if we can do better, i.e., if the - expression is actually pointing at an object whose alignment is tighter. */ + If EXP is not a pointer, 0 is returned. */ unsigned int -get_pointer_alignment (tree exp) +get_pointer_alignment_1 (tree exp, unsigned HOST_WIDE_INT *bitposp) { STRIP_NOPS (exp); if (TREE_CODE (exp) == ADDR_EXPR) - return get_object_alignment (TREE_OPERAND (exp, 0)); + return get_object_alignment_1 (TREE_OPERAND (exp, 0), bitposp); else if (TREE_CODE (exp) == SSA_NAME && POINTER_TYPE_P (TREE_TYPE (exp))) { struct ptr_info_def *pi = SSA_NAME_PTR_INFO (exp); - unsigned align; if (!pi) - return BITS_PER_UNIT; - if (pi->misalign != 0) - align = (pi->misalign & -pi->misalign); - else - align = pi->align; - return align * BITS_PER_UNIT; + { + *bitposp = 0; + return BITS_PER_UNIT; + } + *bitposp = pi->misalign * BITS_PER_UNIT; + return pi->align * BITS_PER_UNIT; } + *bitposp = 0; return POINTER_TYPE_P (TREE_TYPE (exp)) ? BITS_PER_UNIT : 0; } +/* Return the alignment in bits of EXP, a pointer valued expression. + The alignment returned is, by default, the alignment of the thing that + EXP points to. If it is not a POINTER_TYPE, 0 is returned. + + Otherwise, look at the expression to see if we can do better, i.e., if the + expression is actually pointing at an object whose alignment is tighter. */ + +unsigned int +get_pointer_alignment (tree exp) +{ + unsigned HOST_WIDE_INT bitpos = 0; + unsigned int align; + + align = get_pointer_alignment_1 (exp, &bitpos); + + /* align and bitpos now specify known low bits of the pointer. + ptr & (align - 1) == bitpos. */ + + if (bitpos != 0) + align = (bitpos & -bitpos); + + return align; +} + /* Compute the length of a C string. TREE_STRING_LENGTH is not the right way, because it could contain a zero byte in the middle. TREE_STRING_LENGTH is the size of the character array, not the string. @@ -5450,6 +5450,7 @@ extern bool is_builtin_fn (tree); extern unsigned int get_object_alignment_1 (tree, unsigned HOST_WIDE_INT *); extern unsigned int get_object_alignment (tree); extern unsigned int get_object_or_type_alignment (tree); +extern unsigned int get_pointer_alignment_1 (tree, unsigned HOST_WIDE_INT *); extern unsigned int get_pointer_alignment (tree); extern tree fold_call_stmt (gimple, bool); extern tree gimple_fold_builtin_snprintf_chk (gimple, tree, enum built_in_function); |