offby1

Author: ashleynh

src/passes/hash-stringify-walker.cpp

@@ -159,7 +159,7 @@ std::vector<SuffixTree::RepeatedSubstring> StringifyProcessor::removeOverlaps(
     for (auto startIdx : substring.StartIndices) {
       auto interval =
         Interval(startIdx,
-                 startIdx + substring.Length,
+                 startIdx + substring.Length - 1,
                  substring.Length * substring.StartIndices.size());
       intervals.push_back(interval);
       intervalMap[std::move(interval)] = i;
@@ -173,7 +173,7 @@ std::vector<SuffixTree::RepeatedSubstring> StringifyProcessor::removeOverlaps(
     doNotInclude.insert(intervalMap[interval]);
   }
 
-  // Only include non-overlapping substrings
+  // Construct a result with only the substrings that don't overlap
   std::vector<SuffixTree::RepeatedSubstring> result;
   for (Index i = 0; i < substrings.size(); i++) {
     if (doNotInclude.find(i) != doNotInclude.end()) {

test/lit/passes/outlining.wast

@@ -1006,3 +1006,57 @@
     (loop (nop))
   )
 )
+
+;; Test that no attempt is made to outline overlapping repeat substrings
+(module
+  (func $a
+    (drop (i32.add
+      (i32.const 0)
+      (i32.const 1)
+    ))
+    (drop (i32.sub
+      (i32.const 2)
+      (i32.const 3)
+    ))
+    (drop (i32.mul
+      (i32.const 4)
+      (i32.const 5)
+    ))
+    (drop (i32.div_u
+      (i32.const 6)
+      (i32.const 7)
+    ))
+    (drop (i32.add
+      (i32.const 0)
+      (i32.const 1)
+    ))
+    (drop (i32.sub
+      (i32.const 2)
+      (i32.const 3)
+    ))
+    (drop (i32.mul
+      (i32.const 4)
+      (i32.const 5)
+    ))
+    (drop (i32.div_u
+      (i32.const 6)
+      (i32.const 7)
+    ))
+    (drop (i32.sub
+      (i32.const 2)
+      (i32.const 3)
+    ))
+    (drop (i32.mul
+      (i32.const 4)
+      (i32.const 5)
+    ))
+    (drop (i32.sub
+      (i32.const 2)
+      (i32.const 3)
+    ))
+    (drop (i32.mul
+      (i32.const 4)
+      (i32.const 5)
+    ))
+  )
+)