[llvm] r363743 - Recommit [SROA] Enhance SROA to handle `addrspacecast`ed allocas

[Michael Liao via llvm-commits]

Author: hliao
Date: Tue Jun 18 14:41:13 2019
New Revision: 363743

URL: http://llvm.org/viewvc/llvm-project?rev=363743&view=rev
Log:
Recommit [SROA] Enhance SROA to handle `addrspacecast`ed allocas

[SROA] Enhance SROA to handle `addrspacecast`ed allocas

- Fix typo in original change
- Add additional handling to ensure all return pointers are properly
  casted.

Summary:
- After `addrspacecast` is allowed to be eliminated in SROA, the
  adjusting of storage pointer (from `alloca) needs to handle the
  potential different address spaces between the storage pointer (from
  alloca) and the pointer being used.

Reviewers: arsenm

Subscribers: wdng, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63501

Modified:
    llvm/trunk/lib/Transforms/Scalar/SROA.cpp
    llvm/trunk/test/Transforms/SROA/addrspacecast.ll

Modified: llvm/trunk/lib/Transforms/Scalar/SROA.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/SROA.cpp?rev=363743&r1=363742&r2=363743&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/SROA.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/SROA.cpp Tue Jun 18 14:41:13 2019
@@ -1589,6 +1589,12 @@ static Value *getAdjustedPtr(IRBuilderTy
   PointerType *TargetPtrTy = cast<PointerType>(PointerTy);
   Type *TargetTy = TargetPtrTy->getElementType();
 
+  // As `addrspacecast` is , `Ptr` (the storage pointer) may have different
+  // address space from the expected `PointerTy` (the pointer to be used).
+  // Adjust the pointer type based the original storage pointer.
+  auto AS = cast<PointerType>(Ptr->getType())->getAddressSpace();
+  PointerTy = TargetTy->getPointerTo(AS);
+
   do {
     // First fold any existing GEPs into the offset.
     while (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
@@ -1617,7 +1623,7 @@ static Value *getAdjustedPtr(IRBuilderTy
       OffsetBasePtr = Ptr;
       // If we also found a pointer of the right type, we're done.
       if (P->getType() == PointerTy)
-        return P;
+        break;
     }
 
     // Stash this pointer if we've found an i8*.

Modified: llvm/trunk/test/Transforms/SROA/addrspacecast.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SROA/addrspacecast.ll?rev=363743&r1=363742&r2=363743&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/SROA/addrspacecast.ll (original)
+++ llvm/trunk/test/Transforms/SROA/addrspacecast.ll Tue Jun 18 14:41:13 2019
@@ -299,6 +299,21 @@ define void @select_addrspacecast_gv(i1
   ret void
 }
 
+; CHECK-LABEL: @select_addrspacecast_i8(
+; CHECK: [[SEL:%.*]] = select i1 undef, i8 undef, i8 undef
+; CHECK-NEXT: ret i8 [[SEL]]
+define i8 @select_addrspacecast_i8() {
+  %a = alloca i8
+  %b = alloca i8
+
+  %a.ptr = addrspacecast i8* %a to i8 addrspace(1)*
+  %b.ptr = addrspacecast i8* %b to i8 addrspace(1)*
+
+  %ptr = select i1 undef, i8 addrspace(1)* %a.ptr, i8 addrspace(1)* %b.ptr
+  %ret = load i8, i8 addrspace(1)* %ptr
+  ret i8 %ret
+}
+
 !0 = !{!1, !1, i64 0, i64 1}
 !1 = !{!2, i64 1, !"type_0"}
 !2 = !{!"root"}