bc: remove redundant JUMP generation when parsing 'while'

function                                             old     new   delta
zbc_parse_stmt_possibly_auto                        2065    2025     -40
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-40)             Total: -40 bytes
   text	   data	    bss	    dec	    hex	filename
 982035	    485	   7296	 989816	  f1a78	busybox_old
 981995	    485	   7296	 989776	  f1a50	busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 32 insertions, 11 deletions

diff --git a/miscutils/bc.c b/miscutils/bc.c
index 925950d78..af57b3d6c 100644
--- a/miscutils/bc.c
+++ b/miscutils/bc.c
@@ -4175,7 +4175,7 @@ static BC_STATUS zbc_parse_while(BcParse *p)
         BcStatus s;
         BcInstPtr ip;
         size_t *label;
-        size_t n;
+        size_t cond_idx;
 
         s = zbc_lex_next(&p->l);
         if (s) RETURN_STATUS(s);
@@ -4183,10 +4183,10 @@ static BC_STATUS zbc_parse_while(BcParse *p)
         s = zbc_lex_next(&p->l);
         if (s) RETURN_STATUS(s);
 
-        ip.idx = p->func->labels.len;
+        cond_idx = p->func->labels.len;
 
         bc_vec_push(&p->func->labels, &p->func->code.len);
-        bc_vec_push(&p->conds, &ip.idx);
+        bc_vec_push(&p->conds, &cond_idx);
 
         ip.idx = p->func->labels.len;
         ip.func = 1;
@@ -4209,15 +4209,9 @@ static BC_STATUS zbc_parse_while(BcParse *p)
         s = zbc_parse_stmt_fail_if_bare_NLINE(p, false, "while");
         if (s) RETURN_STATUS(s);
 
-        n = *((size_t *) bc_vec_top(&p->conds));
-        bc_parse_push(p, BC_INST_JUMP);
-        bc_parse_pushIndex(p, n);
-
-        label = bc_vec_top(&p->conds);
-
-        dbg_lex("%s:%d BC_INST_JUMP to %d", __func__, __LINE__, *label);
+        dbg_lex("%s:%d BC_INST_JUMP to %d", __func__, __LINE__, cond_idx);
         bc_parse_push(p, BC_INST_JUMP);
-        bc_parse_pushIndex(p, *label);
+        bc_parse_pushIndex(p, cond_idx);
 
         label = bc_vec_item(&p->func->labels, ip.idx);
         dbg_lex("%s:%d rewriting label: %d -> %d", __func__, __LINE__, *label, p->func->code.len);
diff --git a/testsuite/bc.tests b/testsuite/bc.tests
index 987461ebb..0690e9c6f 100755
--- a/testsuite/bc.tests
+++ b/testsuite/bc.tests
@@ -107,6 +107,33 @@ if(1) {
 99
 "
 
+testing "bc continue in if" \
+        "bc" \
+        "\
+11
+21
+11
+31
+99
+" \
+        "" "\
+i=2
+while(i--) {
+        11
+        if(i) {
+                21
+                continue
+                22
+        } else {
+                31
+                continue
+                32
+        }
+        12
+}
+99
+"
+
 tar xJf bc_large.tar.xz
 
 for f in bc*.bc; do