If the OP_COMPUTEDGOTO's source pseudo is defined by an OP_SETVAL
with a label, then this label is the only possible destination of
the computed goto which can then be transformed into a simple branch.
So, convert such computed goto into a simple OP_BR which may then
participate in other flow simplifications.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
simplify.c | 30 ++++++++++++++++++++++++++++++
validation/optim/cgoto01.c | 24 ++++++++++++++++++++++++
2 files changed, 54 insertions(+)
create mode 100644 validation/optim/cgoto01.c
diff --git a/simplify.c b/simplify.c
index e58fb6cf3941..08022c97437a 100644
--- a/simplify.c
+++ b/simplify.c
@@ -2112,6 +2112,34 @@ found:
return REPEAT_CSE;
}
+static int simplify_cgoto(struct instruction *insn)
+{
+ struct basic_block *target, *bb = insn->bb;
+ struct instruction *def;
+ struct multijmp *jmp;
+
+ switch (DEF_OPCODE(def, insn->cond)) {
+ case OP_SETVAL:
+ if (def->val->type != EXPR_LABEL)
+ break;
+ target = def->val->symbol->bb_target;
+ if (!target->ep)
+ return 0;
+ FOR_EACH_PTR(insn->multijmp_list, jmp) {
+ if (jmp->target == target)
+ continue;
+ remove_bb_from_list(&jmp->target->parents, bb, 1);
+ remove_bb_from_list(&bb->children, jmp->target, 1);
+ MARK_CURRENT_DELETED(jmp);
+ } END_FOR_EACH_PTR(jmp);
+ kill_use(&insn->cond);
+ insn->opcode = OP_BR;
+ insn->bb_true = target;
+ return REPEAT_CSE|REPEAT_CFG_CLEANUP;
+ }
+ return 0;
+}
+
int simplify_instruction(struct instruction *insn)
{
unsigned flags;
@@ -2190,6 +2218,8 @@ int simplify_instruction(struct instruction *insn)
return simplify_branch(insn);
case OP_SWITCH:
return simplify_switch(insn);
+ case OP_COMPUTEDGOTO:
+ return simplify_cgoto(insn);
case OP_RANGE:
return simplify_range(insn);
case OP_FADD:
diff --git a/validation/optim/cgoto01.c b/validation/optim/cgoto01.c
new file mode 100644
index 000000000000..94b2c2c429db
--- /dev/null
+++ b/validation/optim/cgoto01.c
@@ -0,0 +1,24 @@
+void abort(void) __attribute__((__noreturn__));
+
+int foo(int a)
+{
+ void *label;
+
+ if (a == a)
+ label = &&L1;
+ else
+ label = &&L2;
+ goto *label;
+L1: return 0;
+L2: abort();
+}
+
+/*
+ * check-name: cgoto01
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-excludes: set\\.
+ * check-output-excludes: jmp
+ * check-output-excludes: call
+ */
--
2.29.2
