Document that MCExpr::Mod is actually remainder.

Document that MCExpr::Div, Mod, and the comparison operators are all
signed operators.

Document that the comparison operators' results are target-dependent.

Document that the behavior of shr is target-dependent.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95619 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Dan Gohman 2010-02-08 23:58:47 +00:00
parent 8609fda0f7
commit 036c130e90
2 changed files with 14 additions and 10 deletions

View File

@ -202,20 +202,24 @@ public:
enum Opcode {
Add, ///< Addition.
And, ///< Bitwise and.
Div, ///< Division.
Div, ///< Signed division.
EQ, ///< Equality comparison.
GT, ///< Greater than comparison.
GTE, ///< Greater than or equal comparison.
GT, ///< Signed greater than comparison (result is either 0 or some
///< target-specific non-zero value)
GTE, ///< Signed greater than or equal comparison (result is either 0 or
///< some target-specific non-zero value).
LAnd, ///< Logical and.
LOr, ///< Logical or.
LT, ///< Less than comparison.
LTE, ///< Less than or equal comparison.
Mod, ///< Modulus.
LT, ///< Signed less than comparison (result is either 0 or
///< some target-specific non-zero value).
LTE, ///< Signed less than or equal comparison (result is either 0 or
///< some target-specific non-zero value).
Mod, ///< Signed remainder.
Mul, ///< Multiplication.
NE, ///< Inequality comparison.
Or, ///< Bitwise or.
Shl, ///< Bitwise shift left.
Shr, ///< Bitwise shift right.
Shl, ///< Shift left.
Shr, ///< Shift right (arithmetic or logical, depending on target)
Sub, ///< Subtraction.
Xor ///< Bitwise exclusive or.
};

View File

@ -252,8 +252,8 @@ bool MCExpr::EvaluateAsRelocatable(MCValue &Res) const {
}
// FIXME: We need target hooks for the evaluation. It may be limited in
// width, and gas defines the result of comparisons differently from Apple
// as (the result is sign extended).
// width, and gas defines the result of comparisons and right shifts
// differently from Apple as.
int64_t LHS = LHSValue.getConstant(), RHS = RHSValue.getConstant();
int64_t Result = 0;
switch (ABE->getOpcode()) {