AMDGPU: Make some packed shuffles free

VOP3P instructions can encode access to either
half of the register.

llvm-svn: 302730
diff --git a/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll b/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll
new file mode 100644
index 0000000..cc756c8
--- /dev/null
+++ b/llvm/test/Analysis/CostModel/AMDGPU/shufflevector.ll
@@ -0,0 +1,43 @@
+; RUN: opt -cost-model -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=gfx900 %s | FileCheck -check-prefixes=GFX9,GCN %s
+; RUN: opt -cost-model -analyze -mtriple=amdgcn-unknown-amdhsa -mcpu=fiji %s | FileCheck -check-prefixes=VI,GCN %s
+
+; GFX9: estimated cost of 0 for {{.*}} shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> zeroinitializer
+define amdgpu_kernel void @shufflevector_00_v2i16(<2 x i16> addrspace(1)* %out, <2 x i16> addrspace(1)* %vaddr) {
+  %vec = load <2 x i16>, <2 x i16> addrspace(1)* %vaddr
+  %shuf = shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> zeroinitializer
+  store <2 x i16> %shuf, <2 x i16> addrspace(1)* %out
+  ret void
+}
+
+; GFX9: estimated cost of 0 for {{.*}} shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> <i32 0, i32 1>
+define amdgpu_kernel void @shufflevector_01_v2i16(<2 x i16> addrspace(1)* %out, <2 x i16> addrspace(1)* %vaddr) {
+  %vec = load <2 x i16>, <2 x i16> addrspace(1)* %vaddr
+  %shuf = shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> <i32 0, i32 1>
+  store <2 x i16> %shuf, <2 x i16> addrspace(1)* %out
+  ret void
+}
+
+; GFX9: estimated cost of 0 for {{.*}} shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> <i32 1, i32 0>
+define amdgpu_kernel void @shufflevector_10_v2i16(<2 x i16> addrspace(1)* %out, <2 x i16> addrspace(1)* %vaddr) {
+  %vec = load <2 x i16>, <2 x i16> addrspace(1)* %vaddr
+  %shuf = shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> <i32 1, i32 0>
+  store <2 x i16> %shuf, <2 x i16> addrspace(1)* %out
+  ret void
+}
+
+; GFX9: estimated cost of 0 for {{.*}} shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> <i32 1, i32 1>
+define amdgpu_kernel void @shufflevector_11_v2i16(<2 x i16> addrspace(1)* %out, <2 x i16> addrspace(1)* %vaddr) {
+  %vec = load <2 x i16>, <2 x i16> addrspace(1)* %vaddr
+  %shuf = shufflevector <2 x i16> %vec, <2 x i16> undef, <2 x i32> <i32 1, i32 1>
+  store <2 x i16> %shuf, <2 x i16> addrspace(1)* %out
+  ret void
+}
+
+; GCN: estimated cost of 2 for {{.*}} shufflevector <2 x i16> %vec0, <2 x i16> %vec1, <2 x i32> <i32 0, i32 2>
+define amdgpu_kernel void @shufflevector_02_v2i16(<2 x i16> addrspace(1)* %out, <2 x i16> addrspace(1)* %vaddr0, <2 x i16> addrspace(1)* %vaddr1) {
+  %vec0 = load <2 x i16>, <2 x i16> addrspace(1)* %vaddr0
+  %vec1 = load <2 x i16>, <2 x i16> addrspace(1)* %vaddr1
+  %shuf = shufflevector <2 x i16> %vec0, <2 x i16> %vec1, <2 x i32> <i32 0, i32 2>
+  store <2 x i16> %shuf, <2 x i16> addrspace(1)* %out
+  ret void
+}