diff options
| author | Linus Torvalds <torvalds@penguin.transmeta.com> | 2003-04-04 12:34:56 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-07 21:00:10 -0700 |
| commit | 44682172e79f96503bf99b7f33cba8cae8a860da (patch) | |
| tree | e444e60b04561ddaf296033b8edccc914c152935 | |
| parent | d97165e1fe7d89c35040c852d455262a95475f4d (diff) | |
| download | sparse-dev-44682172e79f96503bf99b7f33cba8cae8a860da.tar.gz | |
Simplify some constant integer operations. Better to
do it early and have a smaller tree to work on than to
do it late and carry all the crap around until then.
| -rw-r--r-- | evaluate.c | 29 |
1 files changed, 27 insertions, 2 deletions
@@ -198,11 +198,35 @@ static struct symbol * compatible_integer_binop(struct expression *expr, struct return NULL; } +/* + * CAREFUL! We need to get the size and sign of the + * result right! + */ +static void simplify_int_binop(struct expression *expr) +{ + struct expression *left = expr->left, *right = expr->right; + unsigned long long v, l, r, mask; + + if (left->type != EXPR_VALUE || right->type != EXPR_VALUE) + return; + l = left->value; r = right->value; + switch (expr->op) { + case '+': v = l+r; break; + case '-': v = l-r; break; + default: return; + } + mask = 1ULL << (expr->ctype->bit_size-1); + mask = mask | (mask-1); + expr->value = v & mask; + expr->type = EXPR_VALUE; +} + static struct symbol *evaluate_int_binop(struct expression *expr) { struct symbol *ctype = compatible_integer_binop(expr, &expr->left, &expr->right); if (ctype) { expr->ctype = ctype; + simplify_int_binop(expr); return ctype; } return bad_expr_type(expr); @@ -253,10 +277,12 @@ static struct symbol *evaluate_ptr_add(struct expression *expr, struct expressio mul->ctype = size_t_ctype; mul->left = i; mul->right = val; + simplify_int_binop(mul); /* Leave 'add->op' as 'expr->op' - either '+' or '-' */ add->left = ptr; add->right = mul; + simplify_int_binop(add); } return expr->ctype; @@ -695,12 +721,10 @@ static struct symbol *evaluate_dereference(struct expression *expr) examine_symbol_type(ctype); -#if 1 /* Simplify: *&(expr) => (expr) */ if (op->type == EXPR_PREOP && op->op == '&') { *expr = *op->unop; } -#endif expr->ctype = ctype; return ctype; @@ -839,6 +863,7 @@ static struct symbol *evaluate_member_dereference(struct expression *expr) add->right = alloc_expression(expr->pos, EXPR_VALUE); add->right->ctype = &int_ctype; add->right->value = offset; + simplify_int_binop(add); } ctype = member->ctype.base_type; |