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| author | Richard Biener <rguenther@suse.de> | 2024-02-14 12:33:13 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2024-02-14 15:50:48 +0100 |
| commit | ad7a365aaccecd23ea287c7faaab9c7bd50b944a (patch) | |
| tree | 70797be9537cd3d35a476a732a804cb2fa797f78 /gcc/bitmap.cc | |
| parent | a032c319cb9cf5348d71f008f311bcf95f3dac40 (diff) | |
| download | gcc-ad7a365aaccecd23ea287c7faaab9c7bd50b944a.zip gcc-ad7a365aaccecd23ea287c7faaab9c7bd50b944a.tar.gz gcc-ad7a365aaccecd23ea287c7faaab9c7bd50b944a.tar.bz2 | |
tree-optimization/113910 - huge compile time during PTA
For the testcase in PR113910 we spend a lot of time in PTA comparing
bitmaps for looking up equivalence class members. This points to
the very weak bitmap_hash function which effectively hashes set
and a subset of not set bits.
The major problem with it is that it simply truncates the
BITMAP_WORD sized intermediate hash to hashval_t which is
unsigned int, effectively not hashing half of the bits.
This reduces the compile-time for the testcase from tens of minutes
to 42 seconds and PTA time from 99% to 46%.
PR tree-optimization/113910
* bitmap.cc (bitmap_hash): Mix the full element "hash" to
the hashval_t hash.
Diffstat (limited to 'gcc/bitmap.cc')
| -rw-r--r-- | gcc/bitmap.cc | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/gcc/bitmap.cc b/gcc/bitmap.cc index 6cf326b..459e32c 100644 --- a/gcc/bitmap.cc +++ b/gcc/bitmap.cc @@ -2706,7 +2706,7 @@ bitmap_hash (const_bitmap head) for (ix = 0; ix != BITMAP_ELEMENT_WORDS; ix++) hash ^= ptr->bits[ix]; } - return (hashval_t)hash; + return iterative_hash (&hash, sizeof (hash), 0); } |