qbe

commit c5ea06c1360a7bb93cf1a5303f804855a38a82ef
parent c0f25aeae3ef5d5f4b6bc5678f8d8ce40597d673
Author: Quentin Carbonneaux <quentin@c9x.me>
Date:   Mon, 12 Dec 2022 22:36:34 +0100

treat retc as non-escaping

We may well treat all rets as
non-escaping since stack slots
are destroyed upon funcion
return.

Diffstat:
M
alias.c
 | 
3
++-
M
mem.c
 | 
10
++++++++++

2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/alias.c b/alias.c
@@ -192,6 +192,7 @@ fillalias(Fn *fn)
 				}
 			}
 		}
-		esc(b->jmp.arg, fn);
+		if (b->jmp.type != Jretc)
+			esc(b->jmp.arg, fn);
 	}
 }
diff --git a/mem.c b/mem.c
@@ -302,6 +302,11 @@ coalesce(Fn *fn)
 		assert(t->ndef == 1 && t->def);
 		*t->def = (Ins){.op = Onop};
 		for (u=t->use; u<&t->use[t->nuse]; u++) {
+			if (u->type == UJmp) {
+				b = fn->rpo[u->bid];
+				b->jmp.arg = CON_Z;
+				continue;
+			}
 			assert(u->type == UIns);
 			i = u->u.ins;
 			/* make loads crash */
@@ -357,6 +362,11 @@ coalesce(Fn *fn)
 		assert(t->ndef == 1 && t->def);
 		*t->def = (Ins){.op = Onop};
 		for (u=t->use; u<&t->use[t->nuse]; u++) {
+			if (u->type == UJmp) {
+				b = fn->rpo[u->bid];
+				b->jmp.arg = TMP(s->s->t);
+				continue;
+			}
 			assert(u->type == UIns);
 			arg = u->u.ins->arg;
 			for (n=0; n<2; n++)