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| author | Richard Kenner <kenner@gcc.gnu.org> | 1996-03-25 18:48:05 -0500 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1996-03-25 18:48:05 -0500 |
| commit | 65d8b1ce9fbf4b70cd210d04caf700b1506f617f (patch) | |
| tree | fb1889b8ae488c5f7395eb8d4437982b7231fd95 /gcc | |
| parent | fda924283fc7d63021aa52553b6ffe10b586d42d (diff) | |
| download | gcc-65d8b1ce9fbf4b70cd210d04caf700b1506f617f.zip gcc-65d8b1ce9fbf4b70cd210d04caf700b1506f617f.tar.gz gcc-65d8b1ce9fbf4b70cd210d04caf700b1506f617f.tar.bz2 | |
(fold, case BIT_IOR_EXPR): Recognize rotates with variable count.
From-SVN: r11614
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/fold-const.c | 60 |
1 files changed, 44 insertions, 16 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 5901325..2f08ead 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3901,6 +3901,9 @@ fold (expr) case BIT_IOR_EXPR: bit_ior: + { + register enum tree_code code0, code1; + if (integer_all_onesp (arg1)) return omit_one_operand (type, arg1, arg0); if (integer_zerop (arg1)) @@ -3909,28 +3912,53 @@ fold (expr) if (t1 != NULL_TREE) return t1; - /* (a << C1) | (a >> C2) if A is unsigned and C1+C2 is the size of A + /* (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. */ - if ((TREE_CODE (arg0) == RSHIFT_EXPR - || TREE_CODE (arg0) == LSHIFT_EXPR) - && (TREE_CODE (arg1) == RSHIFT_EXPR - || TREE_CODE (arg1) == LSHIFT_EXPR) - && TREE_CODE (arg0) != TREE_CODE (arg1) + code0 = TREE_CODE (arg0); + code1 = TREE_CODE (arg1); + if (((code0 == RSHIFT_EXPR && code1 == LSHIFT_EXPR) + || (code1 == RSHIFT_EXPR && code0 == LSHIFT_EXPR)) && operand_equal_p (TREE_OPERAND (arg0, 0), TREE_OPERAND (arg1,0), 0) - && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0))) - && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST - && TREE_CODE (TREE_OPERAND (arg1, 1)) == INTEGER_CST - && TREE_INT_CST_HIGH (TREE_OPERAND (arg0, 1)) == 0 - && TREE_INT_CST_HIGH (TREE_OPERAND (arg1, 1)) == 0 - && ((TREE_INT_CST_LOW (TREE_OPERAND (arg0, 1)) - + TREE_INT_CST_LOW (TREE_OPERAND (arg1, 1))) + && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg0, 0)))) + { + register tree tree01, tree11; + register enum tree_code code01, code11; + + tree01 = TREE_OPERAND (arg0, 1); + tree11 = TREE_OPERAND (arg1, 1); + code01 = TREE_CODE (tree01); + code11 = TREE_CODE (tree11); + if (code01 == INTEGER_CST + && code11 == INTEGER_CST + && TREE_INT_CST_HIGH (tree01) == 0 + && TREE_INT_CST_HIGH (tree11) == 0 + && ((TREE_INT_CST_LOW (tree01) + TREE_INT_CST_LOW (tree11)) == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))))) - return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0), - TREE_CODE (arg0) == LSHIFT_EXPR - ? TREE_OPERAND (arg0, 1) : TREE_OPERAND (arg1, 1)); + return build (LROTATE_EXPR, type, TREE_OPERAND (arg0, 0), + code0 == LSHIFT_EXPR ? tree01 : tree11); + else if (code11 == MINUS_EXPR + && TREE_CODE (TREE_OPERAND (tree11, 0)) == INTEGER_CST + && TREE_INT_CST_HIGH (TREE_OPERAND (tree11, 0)) == 0 + && TREE_INT_CST_LOW (TREE_OPERAND (tree11, 0)) + == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))) + && operand_equal_p (tree01, TREE_OPERAND (tree11, 1), 0)) + return build (code0 == LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR, + type, TREE_OPERAND (arg0, 0), tree01); + else if (code01 == MINUS_EXPR + && TREE_CODE (TREE_OPERAND (tree01, 0)) == INTEGER_CST + && TREE_INT_CST_HIGH (TREE_OPERAND (tree01, 0)) == 0 + && TREE_INT_CST_LOW (TREE_OPERAND (tree01, 0)) + == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg0, 0))) + && operand_equal_p (tree11, TREE_OPERAND (tree01, 1), 0)) + return build (code0 != LSHIFT_EXPR ? LROTATE_EXPR : RROTATE_EXPR, + type, TREE_OPERAND (arg0, 0), tree11); + } goto associate; + } case BIT_XOR_EXPR: if (integer_zerop (arg1)) |