diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index deb8780b8d5..050d45c6069 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3103,6 +3103,46 @@ distribute_bit_expr (enum tree_code code, tree type, tree arg0, tree arg1) return fold_build2 (TREE_CODE (arg0), type, common, fold_build2 (code, type, left, right)); } + +/* Knowing that ARG0 and ARG1 are both RDIV_EXPRs, simplify a binary operation + with code CODE. This optimization is unsafe. */ +static tree +distribute_real_division (enum tree_code code, tree type, tree arg0, tree arg1) +{ + bool mul0 = TREE_CODE (arg0) == MULT_EXPR; + bool mul1 = TREE_CODE (arg1) == MULT_EXPR; + + /* (A / C) +- (B / C) -> (A +- B) / C. */ + if (mul0 == mul1 + && operand_equal_p (TREE_OPERAND (arg0, 1), + TREE_OPERAND (arg1, 1), 0)) + return fold_build2 (mul0 ? MULT_EXPR : RDIV_EXPR, type, + fold_build2 (code, type, + TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0)), + TREE_OPERAND (arg0, 1)); + + /* (A / C1) +- (A / C2) -> A * (1 / C1 +- 1 / C2). */ + if (operand_equal_p (TREE_OPERAND (arg0, 0), + TREE_OPERAND (arg1, 0), 0) + && TREE_CODE (TREE_OPERAND (arg0, 1)) == REAL_CST + && TREE_CODE (TREE_OPERAND (arg1, 1)) == REAL_CST) + { + REAL_VALUE_TYPE r0, r1; + r0 = TREE_REAL_CST (TREE_OPERAND (arg0, 1)); + r1 = TREE_REAL_CST (TREE_OPERAND (arg1, 1)); + if (!mul0) + real_arithmetic (&r0, RDIV_EXPR, &dconst1, &r0); + if (!mul1) + real_arithmetic (&r1, RDIV_EXPR, &dconst1, &r1); + real_arithmetic (&r0, code, &r0, &r1); + return fold_build2 (MULT_EXPR, type, + TREE_OPERAND (arg0, 0), + build_real (type, r0)); + } + + return NULL_TREE; +} /* Return a BIT_FIELD_REF of type TYPE to refer to BITSIZE bits of INNER starting at BITPOS. The field is unsigned if UNSIGNEDP is nonzero. */ @@ -7528,6 +7568,12 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) fold_convert (type, tem)); } + if (flag_unsafe_math_optimizations + && (TREE_CODE (arg0) == RDIV_EXPR || TREE_CODE (arg0) == MULT_EXPR) + && (TREE_CODE (arg1) == RDIV_EXPR || TREE_CODE (arg1) == MULT_EXPR) + && (tem = distribute_real_division (code, type, arg0, arg1))) + return tem; + /* Convert x+x into x*2.0. */ if (operand_equal_p (arg0, arg1, 0) && SCALAR_FLOAT_TYPE_P (type)) @@ -7925,6 +7971,12 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) return fold_convert (type, fold (tem)); } + if (flag_unsafe_math_optimizations + && (TREE_CODE (arg0) == RDIV_EXPR || TREE_CODE (arg0) == MULT_EXPR) + && (TREE_CODE (arg1) == RDIV_EXPR || TREE_CODE (arg1) == MULT_EXPR) + && (tem = distribute_real_division (code, type, arg0, arg1))) + return tem; + if (TREE_CODE (arg0) == MULT_EXPR && TREE_CODE (arg1) == MULT_EXPR && (!FLOAT_TYPE_P (type) || flag_unsafe_math_optimizations)) |