diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 58 |
1 files changed, 28 insertions, 30 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 57ba334f3b6..a775f2713c1 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -9217,7 +9217,7 @@ fold_comparison (location_t loc, enum tree_code code, tree type, /* Transform comparisons of the form X +- C1 CMP Y +- C2 to X CMP Y +- C2 +- C1 for signed X, Y. This is valid if the resulting offset is smaller in absolute value than the - original one. */ + original one and has the same sign. */ if (TYPE_OVERFLOW_UNDEFINED (TREE_TYPE (arg0)) && (TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) && (TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST @@ -9236,32 +9236,35 @@ fold_comparison (location_t loc, enum tree_code code, tree type, "a comparison"); /* Put the constant on the side where it doesn't overflow and is - of lower absolute value than before. */ + of lower absolute value and of same sign than before. */ cst = int_const_binop (TREE_CODE (arg0) == TREE_CODE (arg1) ? MINUS_EXPR : PLUS_EXPR, const2, const1); if (!TREE_OVERFLOW (cst) - && tree_int_cst_compare (const2, cst) == tree_int_cst_sgn (const2)) + && tree_int_cst_compare (const2, cst) == tree_int_cst_sgn (const2) + && tree_int_cst_sgn (cst) == tree_int_cst_sgn (const2)) { fold_overflow_warning (warnmsg, WARN_STRICT_OVERFLOW_COMPARISON); return fold_build2_loc (loc, code, type, - variable1, - fold_build2_loc (loc, - TREE_CODE (arg1), TREE_TYPE (arg1), - variable2, cst)); + variable1, + fold_build2_loc (loc, TREE_CODE (arg1), + TREE_TYPE (arg1), + variable2, cst)); } cst = int_const_binop (TREE_CODE (arg0) == TREE_CODE (arg1) ? MINUS_EXPR : PLUS_EXPR, const1, const2); if (!TREE_OVERFLOW (cst) - && tree_int_cst_compare (const1, cst) == tree_int_cst_sgn (const1)) + && tree_int_cst_compare (const1, cst) == tree_int_cst_sgn (const1) + && tree_int_cst_sgn (cst) == tree_int_cst_sgn (const1)) { fold_overflow_warning (warnmsg, WARN_STRICT_OVERFLOW_COMPARISON); return fold_build2_loc (loc, code, type, - fold_build2_loc (loc, TREE_CODE (arg0), TREE_TYPE (arg0), - variable1, cst), - variable2); + fold_build2_loc (loc, TREE_CODE (arg0), + TREE_TYPE (arg0), + variable1, cst), + variable2); } } @@ -11222,7 +11225,6 @@ fold_binary_loc (location_t loc, { double_int c1, c2, c3, msk; int width = TYPE_PRECISION (type), w; - bool try_simplify = true; c1 = tree_to_double_int (TREE_OPERAND (arg0, 1)); c2 = tree_to_double_int (arg1); @@ -11259,20 +11261,7 @@ fold_binary_loc (location_t loc, } } - /* If X is a tree of the form (Y * K1) & K2, this might conflict - with that optimization from the BIT_AND_EXPR optimizations. - This could end up in an infinite recursion. */ - if (TREE_CODE (TREE_OPERAND (arg0, 0)) == MULT_EXPR - && TREE_CODE (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1)) - == INTEGER_CST) - { - tree t = TREE_OPERAND (TREE_OPERAND (arg0, 0), 1); - double_int masked = mask_with_tz (type, c3, tree_to_double_int (t)); - - try_simplify = (masked != c1); - } - - if (try_simplify && c3 != c1) + if (c3 != c1) return fold_build2_loc (loc, BIT_IOR_EXPR, type, fold_build2_loc (loc, BIT_AND_EXPR, type, TREE_OPERAND (arg0, 0), @@ -11662,16 +11651,25 @@ fold_binary_loc (location_t loc, && TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST) { + double_int darg1 = tree_to_double_int (arg1); double_int masked - = mask_with_tz (type, tree_to_double_int (arg1), + = mask_with_tz (type, darg1, tree_to_double_int (TREE_OPERAND (arg0, 1))); if (masked.is_zero ()) return omit_two_operands_loc (loc, type, build_zero_cst (type), arg0, arg1); - else if (masked != tree_to_double_int (arg1)) - return fold_build2_loc (loc, code, type, op0, - double_int_to_tree (type, masked)); + else if (masked != darg1) + { + /* Avoid the transform if arg1 is a mask of some + mode which allows further optimizations. */ + int pop = darg1.popcount (); + if (!(pop >= BITS_PER_UNIT + && exact_log2 (pop) != -1 + && double_int::mask (pop) == darg1)) + return fold_build2_loc (loc, code, type, op0, + double_int_to_tree (type, masked)); + } } /* For constants M and N, if M == (1LL << cst) - 1 && (N & M) == M, |