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added some optimalizations

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This commit is contained in:
eck
1990-09-06 11:32:51 +00:00
parent 9915ed4bc2
commit 2f0275ba3c
4 changed files with 51 additions and 19 deletions
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41
lang/cem/cemcom.ansi/ch3bin.c
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@@ -27,8 +27,13 @@ extern char *symbol2str();
depending on the constancy of the operands.
*/
#define commutative_binop(expp, oper, expr) mk_binop(expp, oper, expr, 1)
/*
* Although the relational operators are generally not commutative, we can
* switch the arguments if the operator is adapted (e.g. < becomes >)
*/
#define non_commutative_binop(expp, oper, expr) mk_binop(expp, oper, expr, 0)
#define commutative_binop(expp, oper, expr) mk_binop(expp, oper, expr, 1)
#define non_commutative_relop(expp, oper, expr) mk_binop(expp, oper, expr, 1)
ch3bin(expp, oper, expr)
register struct expr **expp;
@@ -182,7 +187,7 @@ ch3bin(expp, oper, expr)
case EQUAL:
case NOTEQUAL:
relbalance(expp, oper, &expr);
non_commutative_binop(expp, oper, expr);
non_commutative_relop(expp, oper, expr);
(*expp)->ex_type = int_type;
break;
@@ -301,6 +306,23 @@ pntminuspnt(expp, oper, expr)
if (int_size != pointer_size) (*expp)->ex_flags |= EX_PTRDIFF;
}
/*
* The function arg_switched() returns the operator that should be used
* when the arguments are switched. This is special for some relational
* operators.
*/
int
arg_switched(oper)
{
switch (oper) {
case '<': return '>';
case '>': return '<';
case LESSEQ: return GREATEREQ;
case GREATEREQ: return LESSEQ;
default: return oper;
}
}
mk_binop(expp, oper, expr, commutative)
struct expr **expp;
register struct expr *expr;
@@ -315,14 +337,13 @@ mk_binop(expp, oper, expr, commutative)
cstbin(expp, oper, expr);
else if (is_fp_cst(expr) && is_fp_cst(ex))
fltcstbin(expp, oper, expr);
else {
*expp = (commutative &&
! (ex->ex_flags & EX_VOLATILE) &&
( expr->ex_depth > ex->ex_depth ||
(expr->ex_flags & EX_SIDEEFFECTS) ||
is_cp_cst(ex)))
? new_oper(ex->ex_type, expr, oper, ex)
: new_oper(ex->ex_type, ex, oper, expr);
else {
*expp = (commutative
&& !(ex->ex_flags & EX_VOLATILE)
&& ( expr->ex_depth > ex->ex_depth
|| is_cp_cst(ex)))
? new_oper(ex->ex_type, expr, arg_switched(oper), ex)
: new_oper(ex->ex_type, ex, oper, expr);
}
}