diff --git a/src/p_setup.c b/src/p_setup.c
index 1884b6de3..b581e16d3 100644
--- a/src/p_setup.c
+++ b/src/p_setup.c
@@ -1807,7 +1807,7 @@ static void P_LoadMapLUT(const virtres_t *virt)
 		P_CreateBlockMap();
 }
 
-static void P_LoadLineDefs2(void)
+static void P_ProcessLinedefsWithSidedefs(void)
 {
 	size_t i = numlines;
 	register line_t *ld = lines;
@@ -1846,67 +1846,69 @@ static void P_LoadLineDefs2(void)
 			break;
 		}
 	}
+}
 
-	// Optimize sidedefs
-	if (M_CheckParm("-compress"))
+static void P_CompressSidedefs(void)
+{
+	side_t *newsides;
+	size_t numnewsides = 0;
+	size_t z;
+	size_t i;
+
+	for (i = 0; i < numsides; i++)
 	{
-		side_t *newsides;
-		size_t numnewsides = 0;
-		size_t z;
+		size_t j, k;
+		line_t *ld;
 
-		for (i = 0; i < numsides; i++)
+		if (!sides[i].sector)
+			continue;
+
+		for (k = numlines, ld = lines; k--; ld++)
 		{
-			size_t j, k;
-			if (sides[i].sector == NULL)
+			if (ld->sidenum[0] == i)
+				ld->sidenum[0] = (UINT16)numnewsides;
+
+			if (ld->sidenum[1] == i)
+				ld->sidenum[1] = (UINT16)numnewsides;
+		}
+
+		for (j = i + 1; j < numsides; j++)
+		{
+			if (!sides[j].sector)
 				continue;
 
-			for (k = numlines, ld = lines; k--; ld++)
+			if (!memcmp(&sides[i], &sides[j], sizeof(side_t)))
 			{
-				if (ld->sidenum[0] == i)
-					ld->sidenum[0] = (UINT16)numnewsides;
-
-				if (ld->sidenum[1] == i)
-					ld->sidenum[1] = (UINT16)numnewsides;
-			}
-
-			for (j = i+1; j < numsides; j++)
-			{
-				if (sides[j].sector == NULL)
-					continue;
-
-				if (!memcmp(&sides[i], &sides[j], sizeof(side_t)))
+				// Find the linedefs that belong to this one
+				for (k = numlines, ld = lines; k--; ld++)
 				{
-					// Find the linedefs that belong to this one
-					for (k = numlines, ld = lines; k--; ld++)
-					{
-						if (ld->sidenum[0] == j)
-							ld->sidenum[0] = (UINT16)numnewsides;
+					if (ld->sidenum[0] == j)
+						ld->sidenum[0] = (UINT16)numnewsides;
 
-						if (ld->sidenum[1] == j)
-							ld->sidenum[1] = (UINT16)numnewsides;
-					}
-					sides[j].sector = NULL; // Flag for deletion
+					if (ld->sidenum[1] == j)
+						ld->sidenum[1] = (UINT16)numnewsides;
 				}
+				sides[j].sector = NULL; // Flag for deletion
 			}
-			numnewsides++;
 		}
-
-		// We're loading crap into this block anyhow, so no point in zeroing it out.
-		newsides = Z_Malloc(numnewsides * sizeof(*newsides), PU_LEVEL, NULL);
-
-		// Copy the sides to their new block of memory.
-		for (i = 0, z = 0; i < numsides; i++)
-		{
-			if (sides[i].sector != NULL)
-				M_Memcpy(&newsides[z++], &sides[i], sizeof(side_t));
-		}
-
-		CONS_Debug(DBG_SETUP, "Old sides is %s, new sides is %s\n", sizeu1(numsides), sizeu1(numnewsides));
-
-		Z_Free(sides);
-		sides = newsides;
-		numsides = numnewsides;
+		numnewsides++;
 	}
+
+	// We're loading crap into this block anyhow, so no point in zeroing it out.
+	newsides = Z_Malloc(numnewsides*sizeof(*newsides), PU_LEVEL, NULL);
+
+	// Copy the sides to their new block of memory.
+	for (i = 0, z = 0; i < numsides; i++)
+	{
+		if (sides[i].sector)
+			M_Memcpy(&newsides[z++], &sides[i], sizeof(side_t));
+	}
+
+	CONS_Debug(DBG_SETUP, "P_CompressSidedefs: Old sides is %s, new sides is %s\n", sizeu1(numsides), sizeu1(numnewsides));
+
+	Z_Free(sides);
+	sides = newsides;
+	numsides = numnewsides;
 }
 
 //
@@ -2066,7 +2068,9 @@ static void P_LoadMapFromFile(void)
 	P_LoadMapBSP(virt);
 	P_LoadMapLUT(virt);
 
-	P_LoadLineDefs2();
+	P_ProcessLinedefsWithSidedefs();
+	if (M_CheckParm("-compress"))
+		P_CompressSidedefs();
 	P_GroupLines();
 
 	P_MakeMapMD5(virt, &mapmd5);