[llvm] r256035 - [NaryReassociate] allow candidate to have a different type

[Jingyue Wu via llvm-commits]

Author: jingyue
Date: Fri Dec 18 15:36:30 2015
New Revision: 256035

URL: http://llvm.org/viewvc/llvm-project?rev=256035&view=rev
Log:
[NaryReassociate] allow candidate to have a different type

Summary:
If Candiadte may have a different type from GEP, we should bitcast or
pointer cast it to GEP's type so that the later RAUW doesn't complain.

Added a test in nary-gep.ll

Reviewers: tra, meheff

Subscribers: mcrosier, llvm-commits, jholewinski

Differential Revision: http://reviews.llvm.org/D15618

Modified:
    llvm/trunk/lib/Transforms/Scalar/NaryReassociate.cpp
    llvm/trunk/test/Transforms/NaryReassociate/NVPTX/nary-gep.ll

Modified: llvm/trunk/lib/Transforms/Scalar/NaryReassociate.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/NaryReassociate.cpp?rev=256035&r1=256034&r2=256035&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/NaryReassociate.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/NaryReassociate.cpp Fri Dec 18 15:36:30 2015
@@ -421,19 +421,20 @@ GetElementPtrInst *NaryReassociate::tryR
       GEP->getSourceElementType(), SE->getSCEV(GEP->getPointerOperand()),
       IndexExprs, GEP->isInBounds());
 
-  auto *Candidate = findClosestMatchingDominator(CandidateExpr, GEP);
+  Value *Candidate = findClosestMatchingDominator(CandidateExpr, GEP);
   if (Candidate == nullptr)
     return nullptr;
 
-  PointerType *TypeOfCandidate = dyn_cast<PointerType>(Candidate->getType());
-  // Pretty rare but theoretically possible when a numeric value happens to
-  // share CandidateExpr.
-  if (TypeOfCandidate == nullptr)
-    return nullptr;
+  IRBuilder<> Builder(GEP);
+  // Candidate does not necessarily have the same pointer type as GEP. Use
+  // bitcast or pointer cast to make sure they have the same type, so that the
+  // later RAUW doesn't complain.
+  Candidate = Builder.CreateBitOrPointerCast(Candidate, GEP->getType());
+  assert(Candidate->getType() == GEP->getType());
 
   // NewGEP = (char *)Candidate + RHS * sizeof(IndexedType)
   uint64_t IndexedSize = DL->getTypeAllocSize(IndexedType);
-  Type *ElementType = TypeOfCandidate->getElementType();
+  Type *ElementType = GEP->getType()->getElementType();
   uint64_t ElementSize = DL->getTypeAllocSize(ElementType);
   // Another less rare case: because I is not necessarily the last index of the
   // GEP, the size of the type at the I-th index (IndexedSize) is not
@@ -453,8 +454,7 @@ GetElementPtrInst *NaryReassociate::tryR
     return nullptr;
 
   // NewGEP = &Candidate[RHS * (sizeof(IndexedType) / sizeof(Candidate[0])));
-  IRBuilder<> Builder(GEP);
-  Type *IntPtrTy = DL->getIntPtrType(TypeOfCandidate);
+  Type *IntPtrTy = DL->getIntPtrType(GEP->getType());
   if (RHS->getType() != IntPtrTy)
     RHS = Builder.CreateSExtOrTrunc(RHS, IntPtrTy);
   if (IndexedSize != ElementSize) {

Modified: llvm/trunk/test/Transforms/NaryReassociate/NVPTX/nary-gep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/NaryReassociate/NVPTX/nary-gep.ll?rev=256035&r1=256034&r2=256035&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/NaryReassociate/NVPTX/nary-gep.ll (original)
+++ llvm/trunk/test/Transforms/NaryReassociate/NVPTX/nary-gep.ll Fri Dec 18 15:36:30 2015
@@ -123,4 +123,21 @@ define void @reassociate_gep_128(float*
   ret void
 }
 
+%struct.complex = type { float, float }
+
+declare void @bar(%struct.complex*)
+
+define void @different_types(%struct.complex* %input, i64 %i) {
+; CHECK-LABEL: @different_types(
+  %t1 = getelementptr %struct.complex, %struct.complex* %input, i64 %i
+  call void @bar(%struct.complex* %t1)
+  %j = add i64 %i, 5
+  %t2 = getelementptr %struct.complex, %struct.complex* %input, i64 %j, i32 0
+; CHECK: [[cast:[^ ]+]] = bitcast %struct.complex* %t1 to float*
+; CHECK-NEXT: %t2 = getelementptr float, float* [[cast]], i64 10
+; CHECK-NEXT: call void @foo(float* %t2)
+  call void @foo(float* %t2)
+  ret void
+}
+
 declare void @llvm.assume(i1)