[PATCH] D22936: Remove TargetBaseAlign. Keep alignment for stack adjustments.

[Alina Sbirlea via llvm-commits]

asbirlea created this revision.
asbirlea added reviewers: llvm-commits, jlebar.
asbirlea added a subscriber: arsenm.
Herald added a subscriber: mzolotukhin.

TargetBaseAlign is no longer required since LSV checks if target allows misaligned accesses.
A constant defining a base alignment is still needed for stack accesses where alignment can be adjusted.

https://reviews.llvm.org/D22936

Files:
  lib/Transforms/Vectorize/LoadStoreVectorizer.cpp

Index: lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
===================================================================
--- lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -40,9 +40,7 @@
 
 namespace {
 
-// TODO: Remove this
-static const unsigned TargetBaseAlign = 4;
-
+static const unsigned StackAdjustedAlignment = 4;
 typedef SmallVector<Instruction *, 8> InstrList;
 typedef MapVector<Value *, InstrList> InstrListMap;
 
@@ -798,8 +796,8 @@
     // so we can cheat and change it!
     Value *V = GetUnderlyingObject(S0->getPointerOperand(), DL);
     if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(V)) {
-      AI->setAlignment(TargetBaseAlign);
-      Alignment = TargetBaseAlign;
+      AI->setAlignment(StackAdjustedAlignment);
+      Alignment = StackAdjustedAlignment;
     } else {
       return false;
     }
@@ -948,8 +946,8 @@
     // so we can cheat and change it!
     Value *V = GetUnderlyingObject(L0->getPointerOperand(), DL);
     if (AllocaInst *AI = dyn_cast_or_null<AllocaInst>(V)) {
-      AI->setAlignment(TargetBaseAlign);
-      Alignment = TargetBaseAlign;
+      AI->setAlignment(StackAdjustedAlignment);
+      Alignment = StackAdjustedAlignment;
     } else {
       return false;
     }
@@ -1032,7 +1030,5 @@
   bool Fast = false;
   bool Allows = TTI.allowsMisalignedMemoryAccesses(SzInBytes * 8, AddressSpace,
                                                    Alignment, &Fast);
-  // TODO: Remove TargetBaseAlign
-  return !(Allows && Fast) && (Alignment % SzInBytes) != 0 &&
-         (Alignment % TargetBaseAlign) != 0;
+  return !(Allows && Fast) && (Alignment % SzInBytes) != 0;
 }


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