diff options
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/expr.c | 32 |
2 files changed, 25 insertions, 12 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index f10d68b2527..adca8881442 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2007-08-24 Richard Guenther <rguenther@suse.de> + + * expr.c (get_inner_reference): Do computation of bitoffset + from offset in a way we can detect overflow reliably. + 2007-08-24 Jie Zhang <jie.zhang@analog.com> * crtstuff.c (USE_PT_GNU_EH_FRAME): Don't define for uClibc. diff --git a/gcc/expr.c b/gcc/expr.c index dc6615abac0..a3b8132709f 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -5782,7 +5782,6 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize, enum machine_mode mode = VOIDmode; tree offset = size_zero_node; tree bit_offset = bitsize_zero_node; - tree tem; /* First get the mode, signedness, and size. We do this from just the outermost expression. */ @@ -5825,6 +5824,8 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize, *pbitsize = tree_low_cst (size_tree, 1); } + *pmode = mode; + /* Compute cumulative bit-offset for nested component-refs and array-refs, and find the ultimate containing object. */ while (1) @@ -5909,18 +5910,25 @@ get_inner_reference (tree exp, HOST_WIDE_INT *pbitsize, done: /* If OFFSET is constant, see if we can return the whole thing as a - constant bit position. Otherwise, split it up. */ - if (host_integerp (offset, 0) - && 0 != (tem = size_binop (MULT_EXPR, - fold_convert (bitsizetype, offset), - bitsize_unit_node)) - && 0 != (tem = size_binop (PLUS_EXPR, tem, bit_offset)) - && host_integerp (tem, 0)) - *pbitpos = tree_low_cst (tem, 0), *poffset = 0; - else - *pbitpos = tree_low_cst (bit_offset, 0), *poffset = offset; + constant bit position. Make sure to handle overflow during + this conversion. */ + if (host_integerp (offset, 0)) + { + double_int tem = double_int_mul (tree_to_double_int (offset), + uhwi_to_double_int (BITS_PER_UNIT)); + tem = double_int_add (tem, tree_to_double_int (bit_offset)); + if (double_int_fits_in_shwi_p (tem)) + { + *pbitpos = double_int_to_shwi (tem); + *poffset = NULL_TREE; + return exp; + } + } + + /* Otherwise, split it up. */ + *pbitpos = tree_low_cst (bit_offset, 0); + *poffset = offset; - *pmode = mode; return exp; } |