2 files changed, 71 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index 3b0b6b767e2..6a5d5a62e1b 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -326,7 +326,8 @@ static LoadInst *combineLoadToNewType(InstCombiner &IC, LoadInst &LI, Type *NewT
 
   LoadInst *NewLoad = IC.Builder->CreateAlignedLoad(
       IC.Builder->CreateBitCast(Ptr, NewTy->getPointerTo(AS)),
-      LI.getAlignment(), LI.getName() + Suffix);
+      LI.getAlignment(), LI.isVolatile(), LI.getName() + Suffix);
+  NewLoad->setAtomic(LI.getOrdering(), LI.getSynchScope());
   MDBuilder MDB(NewLoad->getContext());
   for (const auto &MDPair : MD) {
     unsigned ID = MDPair.first;
@@ -398,7 +399,8 @@ static StoreInst *combineStoreToNewValue(InstCombiner &IC, StoreInst &SI, Value
 
   StoreInst *NewStore = IC.Builder->CreateAlignedStore(
       V, IC.Builder->CreateBitCast(Ptr, V->getType()->getPointerTo(AS)),
-      SI.getAlignment());
+      SI.getAlignment(), SI.isVolatile());
+  NewStore->setAtomic(SI.getOrdering(), SI.getSynchScope());
   for (const auto &MDPair : MD) {
     unsigned ID = MDPair.first;
     MDNode *N = MDPair.second;
@@ -456,9 +458,9 @@ static StoreInst *combineStoreToNewValue(InstCombiner &IC, StoreInst &SI, Value
 /// later. However, it is risky in case some backend or other part of LLVM is
 /// relying on the exact type loaded to select appropriate atomic operations.
 static Instruction *combineLoadToOperationType(InstCombiner &IC, LoadInst &LI) {
-  // FIXME: We could probably with some care handle both volatile and atomic
-  // loads here but it isn't clear that this is important.
-  if (!LI.isSimple())
+  // FIXME: We could probably with some care handle both volatile and ordered
+  // atomic loads here but it isn't clear that this is important.
+  if (!LI.isUnordered())
     return nullptr;
 
   if (LI.use_empty())
@@ -989,9 +991,9 @@ static Value *likeBitCastFromVector(InstCombiner &IC, Value *V) {
 /// the store instruction as otherwise there is no way to signal whether it was
 /// combined or not: IC.EraseInstFromFunction returns a null pointer.
 static bool combineStoreToValueType(InstCombiner &IC, StoreInst &SI) {
-  // FIXME: We could probably with some care handle both volatile and atomic
-  // stores here but it isn't clear that this is important.
-  if (!SI.isSimple())
+  // FIXME: We could probably with some care handle both volatile and ordered
+  // atomic stores here but it isn't clear that this is important.
+  if (!SI.isUnordered())
     return false;
 
   Value *V = SI.getValueOperand();
diff --git a/llvm/test/Transforms/InstCombine/atomic.ll b/llvm/test/Transforms/InstCombine/atomic.ll
index 7b7f0a576b5..15c1659de96 100644
--- a/llvm/test/Transforms/InstCombine/atomic.ll
+++ b/llvm/test/Transforms/InstCombine/atomic.ll
@@ -206,3 +206,64 @@ block2:
 merge:
   ret i32 0
 }
+
+declare void @clobber()
+
+define i32 @test18(float* %p) {
+; CHECK-LABEL: define i32 @test18(
+; CHECK: load atomic i32, i32* [[A:%.*]] unordered, align 4
+; CHECK: store atomic i32 [[B:%.*]], i32* [[C:%.*]] unordered, align 4
+  %x = load atomic float, float* %p unordered, align 4
+  call void @clobber() ;; keep the load around
+  store atomic float %x, float* %p unordered, align 4
+  ret i32 0
+}
+
+; TODO: probably also legal in this case
+define i32 @test19(float* %p) {
+; CHECK-LABEL: define i32 @test19(
+; CHECK: load atomic float, float* %p seq_cst, align 4
+; CHECK: store atomic float %x, float* %p seq_cst, align 4
+  %x = load atomic float, float* %p seq_cst, align 4
+  call void @clobber() ;; keep the load around
+  store atomic float %x, float* %p seq_cst, align 4
+  ret i32 0
+}
+
+define i32 @test20(i32** %p, i8* %v) {
+; CHECK-LABEL: define i32 @test20(
+; CHECK: store atomic i8* %v, i8** [[D:%.*]] unordered, align 4
+  %cast = bitcast i8* %v to i32*
+  store atomic i32* %cast, i32** %p unordered, align 4
+  ret i32 0
+}
+
+define i32 @test21(i32** %p, i8* %v) {
+; CHECK-LABEL: define i32 @test21(
+; CHECK: store atomic i32* %cast, i32** %p monotonic, align 4
+  %cast = bitcast i8* %v to i32*
+  store atomic i32* %cast, i32** %p monotonic, align 4
+  ret i32 0
+}
+
+define void @pr27490a(i8** %p1, i8** %p2) {
+; CHECK-LABEL: define void @pr27490
+; CHECK: %1 = bitcast i8** %p1 to i64*
+; CHECK: %l1 = load i64, i64* %1, align 8
+; CHECK: %2 = bitcast i8** %p2 to i64*
+; CHECK: store volatile i64 %l1, i64* %2, align 8
+  %l = load i8*, i8** %p1
+  store volatile i8* %l, i8** %p2
+  ret void
+}
+
+define void @pr27490b(i8** %p1, i8** %p2) {
+; CHECK-LABEL: define void @pr27490
+; CHECK: %1 = bitcast i8** %p1 to i64*
+; CHECK: %l1 = load i64, i64* %1, align 8
+; CHECK: %2 = bitcast i8** %p2 to i64*
+; CHECK: store atomic i64 %l1, i64* %2 seq_cst, align 8
+  %l = load i8*, i8** %p1
+  store atomic i8* %l, i8** %p2 seq_cst, align 8
+  ret void
+}