[PATCH] D22119: Extended LoadStoreVectorizer to vectorize subchains.

[Alina Sbirlea via llvm-commits]

asbirlea marked 6 inline comments as done.

================
Comment at: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp:112
@@ +111,3 @@
+  /// \p Chain[0, Index) is the largest vectorizable chain prefix. The elements
+  /// of \p Chain should be all loads or all stores.
+  unsigned getVectorizableEnd(ArrayRef<Value *> Chain, BasicBlock::iterator From,
----------------
Well, it still applies. It's still checking for the existance of those instructions but using the info differently. I shortened the comment somewhat.

================
Comment at: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp:356
@@ -352,3 +355,3 @@
         assert(IM->getParent() == IW->getParent() &&
                "Instructions to move should be in the same basic block");
       }
----------------
Because I accidentally did the updates on this one some time ago :). Then I redid them on the other one.

================
Comment at: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp:449-455
@@ -445,8 +448,9 @@
 
-  for (auto EntryMem : MemoryInstrs) {
-    Value *V = EntryMem.first;
-    unsigned VIdx = EntryMem.second;
-    for (auto EntryChain : ChainInstrs) {
-      Value *VV = EntryChain.first;
-      unsigned VVIdx = EntryChain.second;
+  unsigned Index = 0;
+  for (auto EntryChain : ChainInstrs) {
+    Value *VV = EntryChain.first;
+    unsigned VVIdx = EntryChain.second;
+    for (auto EntryMem : MemoryInstrs) {
+      Value *V = EntryMem.first;
+      unsigned VIdx = EntryMem.second;
       if (isa<LoadInst>(V) && isa<LoadInst>(VV))
----------------
Also updated VV/V and VVIdx/VIdx. They still need different names from InstrIndx, since the same index is used for both Chain and Mem in the loop above, and now we need two.

================
Comment at: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp:623-632
@@ -618,4 +622,12 @@
 
-  for (int Head : Heads) {
-    if (Tails.count(Head))
+  for (unsigned i = 0; i < Heads.size(); i++) {
+    int Head = Heads[i];
+    if (VectorizedValues.count(Instrs[Head]))
+      continue;
+    for (unsigned j = 0; j < Tails.size(); j++)
+      if (Head == Tails[j] && !VectorizedValues.count(Instrs[Heads[j]])) {
+        Head = -1;
+        break;
+      }
+    if (Head < 0)
       continue;
----------------
For Heads it's fine to use the range-based loop (updated). For Tails I need the iterator to get Heads[TailsIterator].


http://reviews.llvm.org/D22119