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| author | Jan Hubicka <hubicka@freesoft.cz> | 1999-10-15 07:46:35 +0200 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 1999-10-14 23:46:35 -0600 |
| commit | ccc5fd95b241d216fb93ff30384593c3b2df846e (patch) | |
| tree | 9de0a736cbc85624d4b101760b56c60be85135f5 /gcc/fold-const.c | |
| parent | f959ff1a09bb1ef2580f6ab1862cf1248a0639cd (diff) | |
| download | gcc-ccc5fd95b241d216fb93ff30384593c3b2df846e.zip gcc-ccc5fd95b241d216fb93ff30384593c3b2df846e.tar.gz gcc-ccc5fd95b241d216fb93ff30384593c3b2df846e.tar.bz2 | |
fold-const.c (fold): Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))).
* fold-const.c (fold): Convert (or (not arg0) (not arg1))
to (not (and (arg0) (arg1))). Similary for and.
From-SVN: r30001
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 5ea6129..f055d23 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -5183,6 +5183,21 @@ fold (expr) if (t1 != NULL_TREE) return t1; + /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))). + + This results in more efficient code for machines without a NAND + instruction. Combine will canonicalize to the first form + which will allow use of NAND instructions provided by the + backend if they exist. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && TREE_CODE (arg1) == BIT_NOT_EXPR) + { + return fold (build1 (BIT_NOT_EXPR, type, + build (BIT_AND_EXPR, type, + TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0)))); + } + /* See if this can be simplified into a rotate first. If that is unsuccessful continue in the association code. */ goto bit_rotate; @@ -5241,6 +5256,22 @@ fold (expr) & (((HOST_WIDE_INT) 1 << prec) - 1)) == 0) return build1 (NOP_EXPR, type, TREE_OPERAND (arg0, 0)); } + + /* Convert (or (not arg0) (not arg1)) to (not (and (arg0) (arg1))). + + This results in more efficient code for machines without a NOR + instruction. Combine will canonicalize to the first form + which will allow use of NOR instructions provided by the + backend if they exist. */ + if (TREE_CODE (arg0) == BIT_NOT_EXPR + && TREE_CODE (arg1) == BIT_NOT_EXPR) + { + return fold (build1 (BIT_NOT_EXPR, type, + build (BIT_IOR_EXPR, type, + TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0)))); + } + goto associate; case BIT_ANDTC_EXPR: |