The code from the first chunk is optimised away when using -O > 0

Index: openjpeg-1.5.1/libopenjpeg/j2k.c
===================================================================
--- openjpeg-1.5.1.orig/libopenjpeg/j2k.c	2013-01-01 01:01:01.000000000 +0000
+++ openjpeg-1.5.1/libopenjpeg/j2k.c	2013-01-01 01:01:01.000000000 +0000
@@ -470,7 +470,7 @@ static void j2k_read_siz(opj_j2k_t *j2k)
 
 	image->comps = (opj_image_comp_t*) opj_calloc(image->numcomps, sizeof(opj_image_comp_t));
 	for (i = 0; i < image->numcomps; i++) {
-		int tmp, w, h;
+		int tmp/*, w, h*/;
 		tmp = cio_read(cio, 1);		/* Ssiz_i */
 		image->comps[i].prec = (tmp & 0x7f) + 1;
 		image->comps[i].sgnd = tmp >> 7;
@@ -507,8 +507,8 @@ static void j2k_read_siz(opj_j2k_t *j2k)
 #endif /* USE_JPWL */
 
 		/* TODO: unused ? */
-		w = int_ceildiv(image->x1 - image->x0, image->comps[i].dx);
-		h = int_ceildiv(image->y1 - image->y0, image->comps[i].dy);
+/*		w = int_ceildiv(image->x1 - image->x0, image->comps[i].dx);
+		h = int_ceildiv(image->y1 - image->y0, image->comps[i].dy);*/
 
 		image->comps[i].resno_decoded = 0;	/* number of resolution decoded */
 		image->comps[i].factor = cp->reduce; /* reducing factor per component */
Index: openjpeg-1.5.1/libopenjpeg/j2k.c
===================================================================
--- openjpeg-1.5.1.orig/libopenjpeg/j2k.c	2013-01-01 01:01:01.000000000 +0000
+++ openjpeg-1.5.1/libopenjpeg/j2k.c	2013-01-01 01:01:01.000000000 +0000
@@ -505,6 +505,14 @@ static void j2k_read_siz(opj_j2k_t *j2k)
 			
 		}
 #endif /* USE_JPWL */
+		{
+			if (!(image->comps[i].dx * image->comps[i].dy)) {
+				opj_event_msg(j2k->cinfo, EVT_ERROR,
+					"JPWL: bad XRsiz_%d/YRsiz_%d (%d x %d)\n",
+					i, i, image->comps[i].dx, image->comps[i].dy);
+					return;
+			}
+		}
 
 		/* TODO: unused ? */
 /*		w = int_ceildiv(image->x1 - image->x0, image->comps[i].dx);