From 291698fe1b5512d72186dfc2400bca85dcb507b1 Mon Sep 17 00:00:00 2001
From: Thomas Lively <7121787+tlively@users.noreply.github.com>
Date: Tue, 5 Apr 2022 08:37:21 -0700
Subject: Fix MemoryPacking bug (#4579)

247f4c20a1 introduced a bug that caused expressions that refer to data segments
to be associated with the wrong segments in the presence of other segments that
have no referring expressions at all.

Fixes #4569.
Fixes #4571.
---
 src/passes/MemoryPacking.cpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/passes/MemoryPacking.cpp b/src/passes/MemoryPacking.cpp
index c6fd0e313..7b4caf11e 100644
--- a/src/passes/MemoryPacking.cpp
+++ b/src/passes/MemoryPacking.cpp
@@ -473,7 +473,6 @@ void MemoryPacking::dropUnusedSegments(std::vector<Memory::Segment>& segments,
   ReferrersMap usedReferrers;
   // Remove segments that are never used
   // TODO: remove unused portions of partially used segments as well
-  size_t newSegIndex = 0;
   for (size_t i = 0; i < segments.size(); ++i) {
     bool used = false;
     auto referrersIt = referrers.find(i);
@@ -494,7 +493,7 @@ void MemoryPacking::dropUnusedSegments(std::vector<Memory::Segment>& segments,
     if (used) {
       usedSegments.push_back(std::move(segments[i]));
       if (hasReferrers) {
-        usedReferrers[newSegIndex++] = std::move(referrersIt->second);
+        usedReferrers[usedSegments.size() - 1] = std::move(referrersIt->second);
       }
     } else if (hasReferrers) {
       // All referrers are data.drops. Make them nops.
-- 
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