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| author | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2010-08-05 19:41:31 +0000 |
|---|---|---|
| committer | rth <rth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2010-08-05 19:41:31 +0000 |
| commit | 7e8d812e44fdbe205c18f462aa3977960d174728 (patch) | |
| tree | ebb0bcbba694540435097fb9c41ec0f70c57ab41 /gcc/simplify-rtx.c | |
| parent | df83cdc0a66a54c7ac5454a2063432a8ada5de9a (diff) | |
| download | gcc-7e8d812e44fdbe205c18f462aa3977960d174728.tar.gz | |
Replace exact_log2(x & -x) in favor of more direct computation.
* toplev.h (ctz_hwi, clz_hwi, ffs_hwi): New.
(floor_log2): Use clz_hwi.
(exact_log2): Use ctz_hwi.
* toplev.c (ctz_hwi, clz_hwi, ffs_hwi): New.
* builtins.c (fold_builtin_bitop): Use them.
* simplify-rtx.c (simplify_const_unary_operation): Likewise.
* combine.c (get_pos_from_mask): Use ctz_hwi.
* double-int.c (double_int_ctz): Likewise.
* explow.c (force_reg): Likewise.
* tree.h (SET_DECL_OFFSET_ALIGN): Use ffs_hwi.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@162920 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 23 |
1 files changed, 9 insertions, 14 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 86de77e1406..a7a91e5d50f 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -1197,10 +1197,8 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode, break; case FFS: - /* Don't use ffs here. Instead, get low order bit and then its - number. If arg0 is zero, this will return 0, as desired. */ arg0 &= GET_MODE_MASK (mode); - val = exact_log2 (arg0 & (- arg0)) + 1; + val = ffs_hwi (arg0); break; case CLZ: @@ -1221,7 +1219,7 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode, val = GET_MODE_BITSIZE (mode); } else - val = exact_log2 (arg0 & -arg0); + val = ctz_hwi (arg0); break; case POPCOUNT: @@ -1351,15 +1349,12 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode, case FFS: hv = 0; - if (l1 == 0) - { - if (h1 == 0) - lv = 0; - else - lv = HOST_BITS_PER_WIDE_INT + exact_log2 (h1 & -h1) + 1; - } + if (l1 != 0) + lv = ffs_hwi (l1); + else if (h1 != 0) + lv = HOST_BITS_PER_WIDE_INT + ffs_hwi (h1); else - lv = exact_log2 (l1 & -l1) + 1; + lv = 0; break; case CLZ: @@ -1376,9 +1371,9 @@ simplify_const_unary_operation (enum rtx_code code, enum machine_mode mode, case CTZ: hv = 0; if (l1 != 0) - lv = exact_log2 (l1 & -l1); + lv = ctz_hwi (l1); else if (h1 != 0) - lv = HOST_BITS_PER_WIDE_INT + exact_log2 (h1 & -h1); + lv = HOST_BITS_PER_WIDE_INT + ctz_hwi (h1); else if (! CTZ_DEFINED_VALUE_AT_ZERO (mode, lv)) lv = GET_MODE_BITSIZE (mode); break; |