[PowerPC] Make AddrSpaceCast noop

PowerPC targets do not use address spaces. As a result, we can get selection
failures with address space casts. This patch makes those casts noops.

Patch by Valentin Churavy.

Differential revision: https://reviews.llvm.org/D43781

llvm-svn: 327877

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.h b/llvm/lib/Target/PowerPC/PPCISelLowering.h
index b3215a84829..4dc1b11e992 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.h
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.h
@@ -884,6 +884,11 @@ namespace llvm {
       }
     };
 
+    bool isNoopAddrSpaceCast(unsigned SrcAS, unsigned DestAS) const override {
+      // Addrspacecasts are always noops.
+      return true;
+    }
+
     bool canReuseLoadAddress(SDValue Op, EVT MemVT, ReuseLoadInfo &RLI,
                              SelectionDAG &DAG,
                              ISD::LoadExtType ET = ISD::NON_EXTLOAD) const;