AtomicExpand: Change return type for shouldExpandAtomicStoreInIR

Use the same enum as the other atomic instructions for consistency, in
preparation for addition of another strategy.

Introduce a new "Expand" option, since the store expansion does not
use cmpxchg. Alternatively, the existing CmpXChg strategy could be
renamed to Expand.

1 files changed, 14 insertions, 3 deletions

diff --git a/llvm/lib/CodeGen/AtomicExpandPass.cpp b/llvm/lib/CodeGen/AtomicExpandPass.cpp
index 45b41ce..05b140b 100644
--- a/llvm/lib/CodeGen/AtomicExpandPass.cpp
+++ b/llvm/lib/CodeGen/AtomicExpandPass.cpp
@@ -77,6 +77,7 @@ private:
   bool expandAtomicLoadToLL(LoadInst *LI);
   bool expandAtomicLoadToCmpXchg(LoadInst *LI);
   StoreInst *convertAtomicStoreToIntegerType(StoreInst *SI);
+  bool tryExpandAtomicStore(StoreInst *SI);
   void expandAtomicStore(StoreInst *SI);
   bool tryExpandAtomicRMW(AtomicRMWInst *AI);
   AtomicRMWInst *convertAtomicXchgToIntegerType(AtomicRMWInst *RMWI);
@@ -271,10 +272,8 @@ bool AtomicExpand::runOnFunction(Function &F) {
         MadeChange = true;
       }
 
-      if (TLI->shouldExpandAtomicStoreInIR(SI)) {
-        expandAtomicStore(SI);
+      if (tryExpandAtomicStore(SI))
         MadeChange = true;
-      }
     } else if (RMWI) {
       // There are two different ways of expanding RMW instructions:
       // - into a load if it is idempotent
@@ -418,6 +417,18 @@ bool AtomicExpand::tryExpandAtomicLoad(LoadInst *LI) {
   }
 }
 
+bool AtomicExpand::tryExpandAtomicStore(StoreInst *SI) {
+  switch (TLI->shouldExpandAtomicStoreInIR(SI)) {
+  case TargetLoweringBase::AtomicExpansionKind::None:
+    return false;
+  case TargetLoweringBase::AtomicExpansionKind::Expand:
+    expandAtomicStore(SI);
+    return true;
+  default:
+    llvm_unreachable("Unhandled case in tryExpandAtomicStore");
+  }
+}
+
 bool AtomicExpand::expandAtomicLoadToLL(LoadInst *LI) {
   IRBuilder<> Builder(LI);