diff --git a/Makefile b/Makefile
index 2670f87..ba5fd3a 100644
--- a/Makefile
+++ b/Makefile
@@ -95,6 +95,6 @@ uninstall:
 	fi
 
 profile:
-	perf stat -r 20 -e L1-dcache-loads,L1-dcache-load-misses,L1-dcache-stores -e cycles bp -f plain -g bp -p Grammar grammars/bp.bp >/dev/null
+	perf stat -r 100 -e L1-dcache-loads,L1-dcache-load-misses,L1-dcache-stores -e cycles bp -f plain -g bp -p Grammar grammars/bp.bp >/dev/null
 
 .PHONY: all clean install install-lib uninstall leaktest splint test tutorial lua profile
diff --git a/match.c b/match.c
index 6c55fbc..0ff6243 100644
--- a/match.c
+++ b/match.c
@@ -364,11 +364,11 @@ static match_t *match(match_ctx_t *ctx, const char *str, pat_t *pat)
         // a special case, but if a pattern invokes itself at a later
         // point, it can be handled with normal recursion.
         // See: left-recursion.md for more details.
-        if (str == pat->args.leftrec.at) {
-            pat->args.leftrec.visited = true;
-            return clone_match(pat->args.leftrec.match);
+        if (str == pat->args.leftrec->at) {
+            pat->args.leftrec->visited = true;
+            return clone_match(pat->args.leftrec->match);
         } else {
-            return match(pat->args.leftrec.ctx, str, pat->args.leftrec.fallback);
+            return match(pat->args.leftrec->ctx, str, pat->args.leftrec->fallback);
         }
     }
     case BP_ANYCHAR: {
@@ -678,7 +678,7 @@ static match_t *match(match_ctx_t *ctx, const char *str, pat_t *pat)
             .type = BP_LEFTRECURSION,
             .start = ref->start, .end = ref->end,
             .min_matchlen = 0, .max_matchlen = -1,
-            .args.leftrec = {
+            .args.leftrec = &(leftrec_info_t){
                 .match = NULL,
                 .visited = false,
                 .at = str,
@@ -702,10 +702,10 @@ static match_t *match(match_ctx_t *ctx, const char *str, pat_t *pat)
 
         match_t *m = match(&ctx2, str, ref);
         // If left recursion was involved, keep retrying while forward progress can be made:
-        if (m && rec_op.args.leftrec.visited) {
+        if (m && rec_op.args.leftrec->visited) {
             while (1) {
                 const char *prev = m->end;
-                rec_op.args.leftrec.match = m;
+                rec_op.args.leftrec->match = m;
                 ctx2.cache = &(cache_t){0};
                 match_t *m2 = match(&ctx2, str, ref);
                 cache_destroy(&ctx2);
diff --git a/pattern.c b/pattern.c
index 9620c5d..9eee45a 100644
--- a/pattern.c
+++ b/pattern.c
@@ -723,7 +723,7 @@ void delete_pat(pat_t **at_pat, bool recursive)
             delete_pat(&pat->args.pat, true);
             break;
         case BP_LEFTRECURSION:
-            delete_pat(&pat->args.leftrec.fallback, true);
+            delete_pat(&pat->args.leftrec->fallback, true);
             break;
         default: break;
         }
diff --git a/pattern.h b/pattern.h
index 7569849..a36885e 100644
--- a/pattern.h
+++ b/pattern.h
@@ -5,6 +5,7 @@
 #define PATTERN__H
 
 #include <stdbool.h>
+#include <stdint.h>
 #include <sys/types.h>
 
 #define UNBOUNDED(pat) ((pat)->max_matchlen == -1)
@@ -47,27 +48,28 @@ enum pattype_e {
 typedef struct pat_s {
     struct pat_s *next, **home;
     enum pattype_e type;
+    uint32_t id;
     const char *start, *end;
     // The bounds of the match length (used for backtracking)
-    size_t min_matchlen;
-    ssize_t max_matchlen; // -1 means unbounded length
+    uint32_t min_matchlen;
+    int32_t max_matchlen; // -1 means unbounded length
     union {
         const char *string;
         struct {
             const char *name;
-            size_t len;
+            uint32_t len;
         } ref;
         struct {
             const char *name;
-            size_t namelen;
+            uint32_t namelen;
             struct pat_s *meaning, *next_def;
         } def;
         struct {
             unsigned char low, high;
         } range;
         struct {
-            size_t min;
-            ssize_t max;
+            uint32_t min;
+            int32_t max;
             struct pat_s *sep, *repeat_pat;
         } repetitions;
         // TODO: use a linked list instead of a binary tree
@@ -77,29 +79,30 @@ typedef struct pat_s {
         struct {
             struct pat_s *pat;
             const char *text;
-            size_t len;
+            uint32_t len;
         } replace;
         struct {
             struct pat_s *capture_pat;
             const char *name;
-            size_t namelen;
+            uint16_t namelen;
             bool backreffable;
         } capture;
-        struct {
-            struct match_s *match;
-            const char *at;
-            struct pat_s *fallback;
-            void *ctx;
-            bool visited;
-        } leftrec;
+        struct leftrec_info_s *leftrec;
         struct {
             const char *start, *end, *msg;
         } error;
         struct pat_s *pat;
     } args;
-    size_t id;
 } pat_t;
 
+typedef struct leftrec_info_s {
+    struct match_s *match;
+    const char *at;
+    struct pat_s *fallback;
+    void *ctx;
+    bool visited;
+} leftrec_info_t;
+
 typedef struct {
     bool success;
     union {