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| author | Jeffrey A Law <law@cygnus.com> | 1999-10-14 08:54:16 +0000 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1999-10-14 02:54:16 -0600 |
| commit | 03e0a65f6e0a4bd3e292e1e6a8328a591ec86f58 (patch) | |
| tree | 9dd5fa34a653eaeb4a14a807b4d0914591d2c07b /gcc | |
| parent | 0918eca0642ecac8d0617d4db57ec90d79eeda42 (diff) | |
| download | gcc-03e0a65f6e0a4bd3e292e1e6a8328a591ec86f58.zip gcc-03e0a65f6e0a4bd3e292e1e6a8328a591ec86f58.tar.gz gcc-03e0a65f6e0a4bd3e292e1e6a8328a591ec86f58.tar.bz2 | |
* fold-const.c (fold): Detect rotates built from BIT_XOR_EXPRs.
From-SVN: r29966
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/fold-const.c | 8 |
2 files changed, 11 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 14cae90..04652a7 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +Thu Oct 14 02:54:13 1999 Jeffrey A Law (law@cygnus.com) + + * fold-const.c (fold): Detect rotates built from BIT_XOR_EXPRs. + Thu Oct 14 02:18:19 1999 Marc Espie <espie@cvs.openbsd.org> * combine.c (simplify_logical): Recognize xor pattern that encodes diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 54eeb45..8327419 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -5097,11 +5097,15 @@ fold (expr) if (t1 != NULL_TREE) return t1; + bit_rotate: /* (A << C1) | (A >> C2) if A is unsigned and C1+C2 is the size of A is a rotate of A by C1 bits. */ /* (A << B) | (A >> (Z - B)) if A is unsigned and Z is the size of A is a rotate of A by B bits. */ + /* Both transformations noted above also apply to when the inner + operation is an XOR. */ + code0 = TREE_CODE (arg0); code1 = TREE_CODE (arg1); if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR) @@ -5170,7 +5174,9 @@ fold (expr) return non_lvalue (convert (type, arg0)); if (integer_all_onesp (arg1)) return fold (build1 (BIT_NOT_EXPR, type, arg0)); - goto associate; + /* See if this can be simplified into a rotate first. If that + is unsuccessful we will jump to the association code. */ + goto bit_rotate; case BIT_AND_EXPR: bit_and: |