backend: fix memory leak from not calling deluses() after replcuses in some places

4 files changed, 11 insertions, 12 deletions

diff --git a/src/ir.c b/src/ir.c
index f34cfaf..c32ff4d 100644
--- a/src/ir.c
+++ b/src/ir.c
@@ -541,9 +541,9 @@ void
 replcuses(Ref from, Ref to)
 {
    assert(from.t == RTMP);
-   for (IRUse *use = instruse[from.i], *next; use; use = next) {
+   for (IRUse *use, *next = instruse[from.i]; (use = next);) {
       Ref *u;
-      int n, j;
+      int n;
       next = use->next;
       if (use->u == from.i) continue;
       if (use->u == USERJUMP) {
@@ -556,15 +556,14 @@ replcuses(Ref from, Ref to)
          n = use->blk->npred;
          if (use->blk->phi.n == 0) continue; /* shouldn't happen */
       } else {
-         u = &instrtab[use->u].l;
-         n = 2;
+         u = instrtab[use->u].oper;
+         n = opnoper[instrtab[use->u].op];
       }
 
-      for (j = 0; j < n; ++j) {
+      for (int j = 0; j < n; ++j) {
          if (u[j].bits == from.bits) {
             u[j].bits = to.bits;
             adduse(use->blk, use->u, to);
-            next = use;
             break;
          }
       }
diff --git a/src/ir_simpl.c b/src/ir_simpl.c
index 1a3eb76..4395c7d 100644
--- a/src/ir_simpl.c
+++ b/src/ir_simpl.c
@@ -91,6 +91,7 @@ doins(Instr *ins, Block *blk, int *curi)
       if (r.bits) {
          *ins = mkinstr0(Onop,0);
          replcuses(mkref(RTMP, ins - instrtab), r);
+         deluses(ins - instrtab);
          return 1;
       }
    }
@@ -103,6 +104,7 @@ doins(Instr *ins, Block *blk, int *curi)
          Ref it = ins->l;
          *ins = mkinstr0(Onop,0);
          replcuses(mkref(RTMP, ins - instrtab), it);
+         deluses(ins - instrtab);
          return 1;
       }
       break;
@@ -243,7 +245,7 @@ simpl(Function *fn)
          int phi = blk->phi.p[i];
          /* delete trivial phis */
          Ref *args = phitab.p[instrtab[phi].l.i],
-               same = *args;
+             same = *args;
          if (same.t == RTMP && instrtab[same.i].op == Ophi) goto Next;
          if (blk->npred > 1) for (int j = 1; j < blk->npred; ++j) {
             if (args[j].bits != same.bits) goto Next;
diff --git a/src/ir_ssa.c b/src/ir_ssa.c
index a1d960f..77474b5 100644
--- a/src/ir_ssa.c
+++ b/src/ir_ssa.c
@@ -14,11 +14,8 @@ copyopt(Function *fn)
          for (int j = 1; j < blk->npred; ++j) {
             if (arg[j].bits != arg->bits) goto Next;
          }
-         /* being conservative here because phis could have circular dependencies? */
-         if (arg->t != RTMP || instrtab[arg->i].op != Ophi) {
-            replcuses(mkref(RTMP, phi), *arg);
-            delphi(blk, i--);
-         }
+         replcuses(mkref(RTMP, phi), *arg);
+         delphi(blk, i--);
       Next:;
       }
       for (int i = 0; i < blk->ins.n; ++i) {
diff --git a/src/ir_stack.c b/src/ir_stack.c
index a9acc61..e77e114 100644
--- a/src/ir_stack.c
+++ b/src/ir_stack.c
@@ -20,6 +20,7 @@ lowerstack(Function *fn)
             if (fn->stksiz > (1<<20)-1) error(NULL, "'%s' stack frame too big", fn->name);
             *ins = mkinstr0(Onop,0);
             replcuses(mkref(RTMP, t), mkref(RSTACK, fn->stksiz-siz));
+            deluses(t);
          }
       }
    } while ((blk = blk->lnext) != fn->entry);