diff options
Diffstat (limited to 'tccgen.c')
| -rw-r--r-- | tccgen.c | 35 |
1 files changed, 25 insertions, 10 deletions
@@ -1476,16 +1476,31 @@ static void gen_opic(int op) c2 = c1; //c = c1, c1 = c2, c2 = c; l2 = l1; //l = l1, l1 = l2, l2 = l; } - /* Filter out NOP operations like x*1, x-0, x&-1... */ - if (c2 && (((op == '*' || op == '/' || op == TOK_UDIV || - op == TOK_PDIV) && - l2 == 1) || - ((op == '+' || op == '-' || op == '|' || op == '^' || - op == TOK_SHL || op == TOK_SHR || op == TOK_SAR) && - l2 == 0) || - (op == '&' && - l2 == -1))) { - /* nothing to do */ + if (!const_wanted && + c1 && ((l1 == 0 && + (op == TOK_SHL || op == TOK_SHR || op == TOK_SAR)) || + (l1 == -1 && op == TOK_SAR))) { + /* treat (0 << x), (0 >> x) and (-1 >> x) as constant */ + vtop--; + } else if (!const_wanted && + c2 && ((l2 == 0 && (op == '&' || op == '*')) || + (l2 == -1 && op == '|') || + (l2 == 0xffffffff && t2 != VT_LLONG && op == '|') || + (l2 == 1 && (op == '%' || op == TOK_UMOD)))) { + /* treat (x & 0), (x * 0), (x | -1) and (x % 1) as constant */ + if (l2 == 1) + vtop->c.ll = 0; + vswap(); + vtop--; + } else if (c2 && (((op == '*' || op == '/' || op == TOK_UDIV || + op == TOK_PDIV) && + l2 == 1) || + ((op == '+' || op == '-' || op == '|' || op == '^' || + op == TOK_SHL || op == TOK_SHR || op == TOK_SAR) && + l2 == 0) || + (op == '&' && + l2 == -1))) { + /* filter out NOP operations like x*1, x-0, x&-1... */ vtop--; } else if (c2 && (op == '*' || op == TOK_PDIV || op == TOK_UDIV)) { /* try to use shifts instead of muls or divs */ |