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-rw-r--r--src/opt.c113
1 files changed, 40 insertions, 73 deletions
diff --git a/src/opt.c b/src/opt.c
index a989670..1dc985a 100644
--- a/src/opt.c
+++ b/src/opt.c
@@ -284,7 +284,7 @@ static void df_join(struct df_domain *dest, const struct df_domain *src) {
*/
struct bfs_opt {
/** The context we're optimizing. */
- const struct bfs_ctx *ctx;
+ struct bfs_ctx *ctx;
/** Data flow state before this expression is evaluated. */
struct df_domain before;
@@ -330,31 +330,22 @@ static void opt_warning(const struct bfs_opt *opt, const struct bfs_expr *expr,
}
/** Create a constant expression. */
-static struct bfs_expr *opt_const(bool value) {
+static struct bfs_expr *opt_const(const struct bfs_opt *opt, bool value) {
static bfs_eval_fn *fns[] = {eval_false, eval_true};
static char *fake_args[] = {"-false", "-true"};
- return bfs_expr_new(fns[value], 1, &fake_args[value]);
-}
-
-/** Extract a child expression, freeing the outer expression. */
-static struct bfs_expr *extract_child_expr(struct bfs_expr *expr, struct bfs_expr **child) {
- struct bfs_expr *ret = *child;
- *child = NULL;
- bfs_expr_free(expr);
- return ret;
+ return bfs_expr_new(opt->ctx, fns[value], 1, &fake_args[value]);
}
/**
* Negate an expression.
*/
-static struct bfs_expr *negate_expr(struct bfs_expr *rhs, char **argv) {
+static struct bfs_expr *negate_expr(const struct bfs_opt *opt, struct bfs_expr *rhs, char **argv) {
if (rhs->eval_fn == eval_not) {
- return extract_child_expr(rhs, &rhs->rhs);
+ return rhs->rhs;
}
- struct bfs_expr *expr = bfs_expr_new(eval_not, 1, argv);
+ struct bfs_expr *expr = bfs_expr_new(opt->ctx, eval_not, 1, argv);
if (!expr) {
- bfs_expr_free(rhs);
return NULL;
}
@@ -373,7 +364,7 @@ static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_e
static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *expr, char **argv) {
bool debug = opt_debug(opt, 1, "De Morgan's laws: %pe ", expr);
- struct bfs_expr *parent = negate_expr(expr, argv);
+ struct bfs_expr *parent = negate_expr(opt, expr, argv);
if (!parent) {
return NULL;
}
@@ -393,10 +384,9 @@ static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *ex
expr->argv = &fake_and_arg;
}
- expr->lhs = negate_expr(expr->lhs, argv);
- expr->rhs = negate_expr(expr->rhs, argv);
+ expr->lhs = negate_expr(opt, expr->lhs, argv);
+ expr->rhs = negate_expr(opt, expr->rhs, argv);
if (!expr->lhs || !expr->rhs) {
- bfs_expr_free(parent);
return NULL;
}
@@ -411,7 +401,6 @@ static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *ex
expr->rhs = optimize_not_expr(opt, expr->rhs);
}
if (!expr->lhs || !expr->rhs) {
- bfs_expr_free(parent);
return NULL;
}
@@ -426,7 +415,6 @@ static struct bfs_expr *de_morgan(const struct bfs_opt *opt, struct bfs_expr *ex
parent = expr;
}
if (!expr) {
- bfs_expr_free(parent);
return NULL;
}
@@ -450,16 +438,15 @@ static struct bfs_expr *optimize_not_expr(const struct bfs_opt *opt, struct bfs_
int optlevel = opt->ctx->optlevel;
if (optlevel >= 1) {
if (rhs->eval_fn == eval_true || rhs->eval_fn == eval_false) {
- struct bfs_expr *ret = opt_const(rhs->eval_fn == eval_false);
+ struct bfs_expr *ret = opt_const(opt, rhs->eval_fn == eval_false);
opt_debug(opt, 1, "constant propagation: %pe <==> %pe\n", expr, ret);
- bfs_expr_free(expr);
return ret;
} else if (rhs->eval_fn == eval_not) {
opt_debug(opt, 1, "double negation: %pe <==> %pe\n", expr, rhs->rhs);
- return extract_child_expr(expr, &rhs->rhs);
+ return rhs->rhs;
} else if (bfs_expr_never_returns(rhs)) {
opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, rhs);
- return extract_child_expr(expr, &expr->rhs);
+ return expr->rhs;
} else if ((rhs->eval_fn == eval_and || rhs->eval_fn == eval_or)
&& (rhs->lhs->eval_fn == eval_not || rhs->rhs->eval_fn == eval_not)) {
return de_morgan(opt, expr, expr->argv);
@@ -480,17 +467,13 @@ static struct bfs_expr *optimize_not_expr_recursive(struct bfs_opt *opt, struct
struct bfs_opt rhs_state = *opt;
expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
if (!expr->rhs) {
- goto fail;
+ return NULL;
}
opt->after_true = rhs_state.after_false;
opt->after_false = rhs_state.after_true;
return optimize_not_expr(opt, expr);
-
-fail:
- bfs_expr_free(expr);
- return NULL;
}
/** Optimize a conjunction. */
@@ -505,18 +488,18 @@ static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_
if (optlevel >= 1) {
if (lhs->eval_fn == eval_true) {
opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, rhs);
- return extract_child_expr(expr, &expr->rhs);
+ return expr->rhs;
} else if (rhs->eval_fn == eval_true) {
opt_debug(opt, 1, "conjunction elimination: %pe <==> %pe\n", expr, lhs);
- return extract_child_expr(expr, &expr->lhs);
+ return expr->lhs;
} else if (lhs->always_false) {
opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
- return extract_child_expr(expr, &expr->lhs);
+ return expr->lhs;
} else if (lhs->always_true && rhs->eval_fn == eval_false) {
bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
- struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
- ret = negate_expr(ret, &fake_not_arg);
+ struct bfs_expr *ret = expr->lhs;
+ ret = negate_expr(opt, ret, &fake_not_arg);
if (debug && ret) {
cfprintf(ctx->cerr, "%pe\n", ret);
}
@@ -524,7 +507,7 @@ static struct bfs_expr *optimize_and_expr(const struct bfs_opt *opt, struct bfs_
} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_false) {
opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
- return extract_child_expr(expr, &expr->rhs);
+ return expr->rhs;
} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
return de_morgan(opt, expr, expr->lhs->argv);
}
@@ -544,14 +527,14 @@ static struct bfs_expr *optimize_and_expr_recursive(struct bfs_opt *opt, struct
struct bfs_opt lhs_state = *opt;
expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
if (!expr->lhs) {
- goto fail;
+ return NULL;
}
struct bfs_opt rhs_state = *opt;
rhs_state.before = lhs_state.after_true;
expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
if (!expr->rhs) {
- goto fail;
+ return NULL;
}
opt->after_true = rhs_state.after_true;
@@ -559,10 +542,6 @@ static struct bfs_expr *optimize_and_expr_recursive(struct bfs_opt *opt, struct
df_join(&opt->after_false, &rhs_state.after_false);
return optimize_and_expr(opt, expr);
-
-fail:
- bfs_expr_free(expr);
- return NULL;
}
/** Optimize a disjunction. */
@@ -578,17 +557,17 @@ static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_e
if (lhs->always_true) {
opt_debug(opt, 1, "short-circuit: %pe <==> %pe\n", expr, lhs);
opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
- return extract_child_expr(expr, &expr->lhs);
+ return expr->lhs;
} else if (lhs->eval_fn == eval_false) {
opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, rhs);
- return extract_child_expr(expr, &expr->rhs);
+ return expr->rhs;
} else if (rhs->eval_fn == eval_false) {
opt_debug(opt, 1, "disjunctive syllogism: %pe <==> %pe\n", expr, lhs);
- return extract_child_expr(expr, &expr->lhs);
+ return expr->lhs;
} else if (lhs->always_false && rhs->eval_fn == eval_true) {
bool debug = opt_debug(opt, 1, "strength reduction: %pe <==> ", expr);
- struct bfs_expr *ret = extract_child_expr(expr, &expr->lhs);
- ret = negate_expr(ret, &fake_not_arg);
+ struct bfs_expr *ret = expr->lhs;
+ ret = negate_expr(opt, ret, &fake_not_arg);
if (debug && ret) {
cfprintf(ctx->cerr, "%pe\n", ret);
}
@@ -596,7 +575,7 @@ static struct bfs_expr *optimize_or_expr(const struct bfs_opt *opt, struct bfs_e
} else if (optlevel >= 2 && lhs->pure && rhs->eval_fn == eval_true) {
opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
- return extract_child_expr(expr, &expr->rhs);
+ return expr->rhs;
} else if (lhs->eval_fn == eval_not && rhs->eval_fn == eval_not) {
return de_morgan(opt, expr, expr->lhs->argv);
}
@@ -616,14 +595,14 @@ static struct bfs_expr *optimize_or_expr_recursive(struct bfs_opt *opt, struct b
struct bfs_opt lhs_state = *opt;
expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
if (!expr->lhs) {
- goto fail;
+ return NULL;
}
struct bfs_opt rhs_state = *opt;
rhs_state.before = lhs_state.after_false;
expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
if (!expr->rhs) {
- goto fail;
+ return NULL;
}
opt->after_false = rhs_state.after_false;
@@ -631,10 +610,6 @@ static struct bfs_expr *optimize_or_expr_recursive(struct bfs_opt *opt, struct b
df_join(&opt->after_true, &rhs_state.after_true);
return optimize_or_expr(opt, expr);
-
-fail:
- bfs_expr_free(expr);
- return NULL;
}
/** Optimize an expression in an ignored-result context. */
@@ -646,23 +621,22 @@ static struct bfs_expr *ignore_result(const struct bfs_opt *opt, struct bfs_expr
if (expr->eval_fn == eval_not) {
opt_debug(opt, 1, "ignored result: %pe --> %pe\n", expr, expr->rhs);
opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
- expr = extract_child_expr(expr, &expr->rhs);
+ expr = expr->rhs;
} else if (optlevel >= 2
&& (expr->eval_fn == eval_and || expr->eval_fn == eval_or || expr->eval_fn == eval_comma)
&& expr->rhs->pure) {
opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, expr->lhs);
opt_warning(opt, expr->rhs, "The result of this expression is ignored.\n\n");
- expr = extract_child_expr(expr, &expr->lhs);
+ expr = expr->lhs;
} else {
break;
}
}
if (optlevel >= 2 && expr->pure && expr->eval_fn != eval_false) {
- struct bfs_expr *ret = opt_const(false);
+ struct bfs_expr *ret = opt_const(opt, false);
opt_debug(opt, 2, "ignored result: %pe --> %pe\n", expr, ret);
opt_warning(opt, expr, "The result of this expression is ignored.\n\n");
- bfs_expr_free(expr);
return ret;
}
}
@@ -684,15 +658,15 @@ static struct bfs_expr *optimize_comma_expr(const struct bfs_opt *opt, struct bf
if (bfs_expr_never_returns(lhs)) {
opt_debug(opt, 1, "reachability: %pe <==> %pe\n", expr, lhs);
opt_warning(opt, expr->rhs, "This expression is unreachable.\n\n");
- return extract_child_expr(expr, &expr->lhs);
+ return expr->lhs;
} else if ((lhs->always_true && rhs->eval_fn == eval_true)
|| (lhs->always_false && rhs->eval_fn == eval_false)) {
opt_debug(opt, 1, "redundancy elimination: %pe <==> %pe\n", expr, lhs);
- return extract_child_expr(expr, &expr->lhs);
+ return expr->lhs;
} else if (optlevel >= 2 && lhs->pure) {
opt_debug(opt, 2, "purity: %pe <==> %pe\n", expr, rhs);
opt_warning(opt, expr->lhs, "The result of this expression is ignored.\n\n");
- return extract_child_expr(expr, &expr->rhs);
+ return expr->rhs;
}
}
@@ -710,7 +684,7 @@ static struct bfs_expr *optimize_comma_expr_recursive(struct bfs_opt *opt, struc
struct bfs_opt lhs_state = *opt;
expr->lhs = optimize_expr_recursive(&lhs_state, expr->lhs);
if (!expr->lhs) {
- goto fail;
+ return NULL;
}
struct bfs_opt rhs_state = *opt;
@@ -719,14 +693,10 @@ static struct bfs_expr *optimize_comma_expr_recursive(struct bfs_opt *opt, struc
expr->rhs = optimize_expr_recursive(&rhs_state, expr->rhs);
if (!expr->rhs) {
- goto fail;
+ return NULL;
}
return optimize_comma_expr(opt, expr);
-
-fail:
- bfs_expr_free(expr);
- return NULL;
}
/** Optimize an icmp-style ([+-]N) expression. */
@@ -1213,10 +1183,9 @@ static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_
opt->after_false = opt->before;
if (optlevel >= 2 && df_is_bottom(&opt->before)) {
- struct bfs_expr *ret = opt_const(false);
+ struct bfs_expr *ret = opt_const(opt, false);
opt_debug(opt, 2, "reachability: %pe --> %pe\n", expr, ret);
opt_warning(opt, expr, "This expression is unreachable.\n\n");
- bfs_expr_free(expr);
return ret;
}
@@ -1257,10 +1226,9 @@ static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_
if (df_is_bottom(&opt->after_true)) {
if (expr->pure) {
- struct bfs_expr *ret = opt_const(false);
+ struct bfs_expr *ret = opt_const(opt, false);
opt_warning(opt, expr, "This expression is always false.\n\n");
opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
- bfs_expr_free(expr);
return ret;
} else {
expr->always_false = true;
@@ -1268,10 +1236,9 @@ static struct bfs_expr *optimize_expr_recursive(struct bfs_opt *opt, struct bfs_
}
} else if (df_is_bottom(&opt->after_false)) {
if (expr->pure) {
- struct bfs_expr *ret = opt_const(true);
+ struct bfs_expr *ret = opt_const(opt, true);
opt_debug(opt, 2, "data flow: %pe --> %pe\n", expr, ret);
opt_warning(opt, expr, "This expression is always true.\n\n");
- bfs_expr_free(expr);
return ret;
} else {
expr->always_true = true;
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 17:18:20 +0000