diff options
Diffstat (limited to 'gcc/toplev.c')
| -rw-r--r-- | gcc/toplev.c | 50 |
1 files changed, 31 insertions, 19 deletions
diff --git a/gcc/toplev.c b/gcc/toplev.c index 2741be5..e180394 100644 --- a/gcc/toplev.c +++ b/gcc/toplev.c @@ -1248,36 +1248,48 @@ read_integral_parameter (const char *p, const char *pname, const int defval) return atoi (p); } -/* Return the logarithm of X, base 2, considering X unsigned, - if X is a power of 2. Otherwise, returns -1. +/* Given X, an unsigned number, return the largest int Y such that 2**Y <= X. + If X is 0, return -1. - This should be used via the `exact_log2' macro. */ + This should be used via the floor_log2 macro. */ int -exact_log2_wide (unsigned HOST_WIDE_INT x) +floor_log2_wide (unsigned HOST_WIDE_INT x) { - int log = 0; - /* Test for 0 or a power of 2. */ - if (x == 0 || x != (x & -x)) + int t=0; + if (x == 0) return -1; - while ((x >>= 1) != 0) - log++; - return log; + if (sizeof (HOST_WIDE_INT)*8 > 64) + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+64))) + t += 64; + if (sizeof (HOST_WIDE_INT)*8 > 32) + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+32))) + t += 32; + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+16))) + t += 16; + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+8))) + t += 8; + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+4))) + t += 4; + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+2))) + t += 2; + if (x >= (unsigned HOST_WIDE_INT)(1 << (t+1))) + t += 1; + return t; } -/* Given X, an unsigned number, return the largest int Y such that 2**Y <= X. - If X is 0, return -1. +/* Return the logarithm of X, base 2, considering X unsigned, + if X is a power of 2. Otherwise, returns -1. - This should be used via the floor_log2 macro. */ + This should be used via the `exact_log2' macro. */ int -floor_log2_wide (unsigned HOST_WIDE_INT x) +exact_log2_wide (unsigned HOST_WIDE_INT x) { - int log = -1; - while (x != 0) - log++, - x >>= 1; - return log; + /* Test for 0 or a power of 2. */ + if (x == 0 || x != (x & -x)) + return -1; + return floor_log2_wide (x); } /* Handler for fatal signals, such as SIGSEGV. These are transformed |