[PATCH] D151640: [LSV] Attempt to fix comparison of APInt's with different bit widths.

[Justin Lebar via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG420cf6927c35: [LSV] Return same bitwidth from getConstantOffset. (authored by jlebar).
Herald added subscribers: kerbowa, jvesely.

Changed prior to commit:
  https://reviews.llvm.org/D151640?vs=526381&id=526447#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D151640/new/

https://reviews.llvm.org/D151640

Files:
  llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
  llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/vect-ptr-ptr-size-mismatch.ll


Index: llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/vect-ptr-ptr-size-mismatch.ll
===================================================================
--- llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/vect-ptr-ptr-size-mismatch.ll
+++ llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/vect-ptr-ptr-size-mismatch.ll
@@ -62,6 +62,23 @@
   unreachable
 }
 
+; CHECK-LABEL: @select_different_as
+; CHECK: load <2 x i32>
+define void @select_different_as(ptr addrspace(1) %p0, ptr addrspace(5) %q0, i1 %cond) {
+entry:
+  %p1 = getelementptr inbounds i32, ptr addrspace(1) %p0, i64 1
+  %q1 = getelementptr inbounds i32, ptr addrspace(5) %q0, i64 1
+  %p0.ascast = addrspacecast ptr addrspace(1) %p0 to ptr
+  %p1.ascast = addrspacecast ptr addrspace(1) %p1 to ptr
+  %q0.ascast = addrspacecast ptr addrspace(5) %q0 to ptr
+  %q1.ascast = addrspacecast ptr addrspace(5) %q1 to ptr
+  %sel0 = select i1 %cond, ptr %p0.ascast, ptr %q0.ascast
+  %sel1 = select i1 %cond, ptr %p1.ascast, ptr %q1.ascast
+  %tmp1 = load i32, ptr %sel0, align 8
+  %tmp2 = load i32, ptr %sel1, align 8
+  unreachable
+}
+
 ; CHECK-LABEL: @shrink_ptr
 ; CHECK: load <2 x i32>
 define void @shrink_ptr(ptr %p) {
Index: llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
+++ llvm/lib/Transforms/Vectorize/LoadStoreVectorizer.cpp
@@ -1441,8 +1441,7 @@
       if (Offset.has_value()) {
         // `Offset` might not have the expected number of bits, if e.g. AS has a
         // different number of bits than opaque pointers.
-        ChainIter->second.push_back(
-            ChainElem{I, Offset.value().sextOrTrunc(ASPtrBits)});
+        ChainIter->second.push_back(ChainElem{I, Offset.value()});
         // Move ChainIter to the front of the MRU list.
         MRU.remove(*ChainIter);
         MRU.push_front(*ChainIter);
@@ -1475,9 +1474,11 @@
   LLVM_DEBUG(dbgs() << "LSV: getConstantOffset, PtrA=" << *PtrA
                     << ", PtrB=" << *PtrB << ", ContextInst= " << *ContextInst
                     << ", Depth=" << Depth << "\n");
-  unsigned OffsetBitWidth = DL.getIndexTypeSizeInBits(PtrA->getType());
-  APInt OffsetA(OffsetBitWidth, 0);
-  APInt OffsetB(OffsetBitWidth, 0);
+  // We'll ultimately return a value of this bit width, even if computations
+  // happen in a different width.
+  unsigned OrigBitWidth = DL.getIndexTypeSizeInBits(PtrA->getType());
+  APInt OffsetA(OrigBitWidth, 0);
+  APInt OffsetB(OrigBitWidth, 0);
   PtrA = PtrA->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetA);
   PtrB = PtrB->stripAndAccumulateInBoundsConstantOffsets(DL, OffsetB);
   unsigned NewPtrBitWidth = DL.getTypeStoreSizeInBits(PtrA->getType());
@@ -1493,7 +1494,7 @@
   OffsetA = OffsetA.sextOrTrunc(NewPtrBitWidth);
   OffsetB = OffsetB.sextOrTrunc(NewPtrBitWidth);
   if (PtrA == PtrB)
-    return OffsetB - OffsetA;
+    return (OffsetB - OffsetA).sextOrTrunc(OrigBitWidth);
 
   // Try to compute B - A.
   const SCEV *DistScev = SE.getMinusSCEV(SE.getSCEV(PtrB), SE.getSCEV(PtrA));
@@ -1501,11 +1502,13 @@
     LLVM_DEBUG(dbgs() << "LSV: SCEV PtrB - PtrA =" << *DistScev << "\n");
     ConstantRange DistRange = SE.getSignedRange(DistScev);
     if (DistRange.isSingleElement())
-      return OffsetB - OffsetA + *DistRange.getSingleElement();
+      return (OffsetB - OffsetA + *DistRange.getSingleElement())
+          .sextOrTrunc(OrigBitWidth);
   }
   std::optional<APInt> Diff =
       getConstantOffsetComplexAddrs(PtrA, PtrB, ContextInst, Depth);
   if (Diff.has_value())
-    return OffsetB - OffsetA + Diff->sext(OffsetB.getBitWidth());
+    return (OffsetB - OffsetA + Diff->sext(OffsetB.getBitWidth()))
+        .sextOrTrunc(OrigBitWidth);
   return std::nullopt;
 }


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