[git commit] bc: remove redundant JUMP generation when parsing 'while'

[Denys Vlasenko]

commit: https://git.busybox.net/busybox/commit/?id=de24e9d3669e43a5419c7990ad13368ae51ced96
branch: https://git.busybox.net/busybox/commit/?id=refs/heads/master

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 at googlemail.com>
---
 miscutils/bc.c     | 16 +++++-----------
 testsuite/bc.tests | 27 +++++++++++++++++++++++++++
 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