[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@327877 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/PowerPC/PPCISelLowering.h b/lib/Target/PowerPC/PPCISelLowering.h
index b3215a8..4dc1b11 100644 (file)
--- a/lib/Target/PowerPC/PPCISelLowering.h
+++ b/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;

diff --git a/test/CodeGen/PowerPC/addrspacecast.ll b/test/CodeGen/PowerPC/addrspacecast.ll
new file mode 100644 (file)
index 0000000..db9d481
--- /dev/null
+++ b/test/CodeGen/PowerPC/addrspacecast.ll
@@ -0,0 +1,22 @@
+; RUN: llc -mtriple=powerpc64le-unknown-linux-gnu %s -o - | FileCheck %s
+
+; Check that codegen for an addrspace cast succeeds without error.
+define <4 x i32 addrspace(1)*> @f (<4 x i32*> %x) {
+  %1 = addrspacecast <4 x i32*> %x to <4 x i32 addrspace(1)*>
+  ret <4 x i32 addrspace(1)*> %1
+  ; CHECK-LABEL: @f
+}
+
+; Check that fairly complicated addrspace cast and operations succeed without error.
+%struct = type opaque
+define void @g (%struct addrspace(10)** %x) {
+  %1 = load %struct addrspace(10)*, %struct addrspace(10)** %x
+  %2 = addrspacecast %struct addrspace(10)* %1 to %struct addrspace(11)*
+  %3 = bitcast %struct addrspace(11)* %2 to i8 addrspace(11)*
+  %4 = getelementptr i8, i8 addrspace(11)* %3, i64 16
+  %5 = bitcast i8 addrspace(11)* %4 to %struct addrspace(10)* addrspace(11)*
+  %6 = load %struct addrspace(10)*, %struct addrspace(10)* addrspace(11)* %5
+  store %struct addrspace(10)* %6, %struct addrspace(10)** undef
+  ret void
+  ; CHECK-LABEL: @g
+}