[InferAddressSpaces] Enhance the handling of cosntexpr.

Summary:
- Constant expressions may not be added in strict postorder as the
  forward instruction scan order. Thus, for a constant express (CE0), if
  its operand (CE1) is used in an previous instruction, they are not in
  postorder. However, different from
  `cloneInstructionWithNewAddressSpace`,
  `cloneConstantExprWithNewAddressSpace` doesn't bookkeep uninferred
  instructions for later resolving. That results in failure of inferring
  constant address.
- This patch adds the support to infer constant expression operand
  recursively, since there won't be loop, if that operand is another
  constant expression.

Reviewers: arsenm

Subscribers: jholewinski, jvesely, wdng, nhaehnle, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61760

llvm-svn: 360431

1 files changed, 10 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
index a59248cc8c5..36115e96cf4 100644
--- a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
+++ b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
@@ -553,10 +553,17 @@ static Value *cloneConstantExprWithNewAddressSpace(
     if (Value *NewOperand = ValueWithNewAddrSpace.lookup(Operand)) {
       IsNew = true;
       NewOperands.push_back(cast<Constant>(NewOperand));
-    } else {
-      // Otherwise, reuses the old operand.
-      NewOperands.push_back(Operand);
+      continue;
     }
+    if (auto CExpr = dyn_cast<ConstantExpr>(Operand))
+      if (Value *NewOperand = cloneConstantExprWithNewAddressSpace(
+              CExpr, NewAddrSpace, ValueWithNewAddrSpace)) {
+        IsNew = true;
+        NewOperands.push_back(cast<Constant>(NewOperand));
+        continue;
+      }
+    // Otherwise, reuses the old operand.
+    NewOperands.push_back(Operand);
   }
 
   // If !IsNew, we will replace the Value with itself. However, replaced values