AMDGPU: enable 128-bit for local addr space under an option

Author: Samuel Pitoiset

ds_read_b128 and ds_write_b128 have been recently enabled
under the amdgpu-ds128 option because the performance benefit
is unclear.

Though, using 128-bit loads/stores for the local address space
appears to introduce regressions in tessellation shaders. Not
sure what is broken, but as ds_read_b128/ds_write_b128 are not
enabled by default, just introduce a global option and enable
128-bit only if requested (until it's fixed/used correctly).

v2: - fix regressions in merge-stores.ll and multiple_tails.ll

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=105464
llvm-svn: 329764
diff --git a/llvm/lib/Target/AMDGPU/AMDGPU.td b/llvm/lib/Target/AMDGPU/AMDGPU.td
index ff6baf7..b419334 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPU.td
+++ b/llvm/lib/Target/AMDGPU/AMDGPU.td
@@ -426,6 +426,12 @@
   "Enable SI Machine Scheduler"
 >;
 
+def FeatureEnableDS128 : SubtargetFeature<"enable-ds128",
+  "EnableDS128",
+  "true",
+  "Use ds_{read|write}_b128"
+>;
+
 // Unless +-flat-for-global is specified, turn on FlatForGlobal for
 // all OS-es on VI and newer hardware to avoid assertion failures due
 // to missing ADDR64 variants of MUBUF instructions.
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
index 27b5799..07ed04e 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.cpp
@@ -132,6 +132,7 @@
     EnableLoadStoreOpt(false),
     EnableUnsafeDSOffsetFolding(false),
     EnableSIScheduler(false),
+    EnableDS128(false),
     DumpCode(false),
 
     FP64(false),
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
index e3455d3..cd08026 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
+++ b/llvm/lib/Target/AMDGPU/AMDGPUSubtarget.h
@@ -133,6 +133,7 @@
   bool EnableLoadStoreOpt;
   bool EnableUnsafeDSOffsetFolding;
   bool EnableSIScheduler;
+  bool EnableDS128;
   bool DumpCode;
 
   // Subtarget statically properties set by tablegen
@@ -412,8 +413,8 @@
 
   /// \returns If target supports ds_read/write_b128 and user enables generation
   /// of ds_read/write_b128.
-  bool useDS128(bool UserEnable) const {
-    return CIInsts && UserEnable;
+  bool useDS128() const {
+    return CIInsts && EnableDS128;
   }
 
   /// \returns If MUBUF instructions always perform range checking, even for
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
index 9f097cd..bf560a9 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp
@@ -265,11 +265,13 @@
     return 512;
   }
 
-  if (AddrSpace == AS.FLAT_ADDRESS ||
-      AddrSpace == AS.LOCAL_ADDRESS ||
-      AddrSpace == AS.REGION_ADDRESS)
+  if (AddrSpace == AS.FLAT_ADDRESS)
     return 128;
 
+  if (AddrSpace == AS.LOCAL_ADDRESS ||
+      AddrSpace == AS.REGION_ADDRESS)
+    return ST->useDS128() ? 128 : 64;
+
   if (AddrSpace == AS.PRIVATE_ADDRESS)
     return 8 * ST->getMaxPrivateElementSize();
 
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index 6f68f63..0829962 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -94,11 +94,6 @@
   cl::desc("Use GPR indexing mode instead of movrel for vector indexing"),
   cl::init(false));
 
-static cl::opt<bool> EnableDS128(
-  "amdgpu-ds128",
-  cl::desc("Use DS_read/write_b128"),
-  cl::init(false));
-
 static cl::opt<unsigned> AssumeFrameIndexHighZeroBits(
   "amdgpu-frame-index-zero-bits",
   cl::desc("High bits of frame index assumed to be zero"),
@@ -5300,7 +5295,7 @@
     }
   } else if (AS == AMDGPUASI.LOCAL_ADDRESS) {
     // Use ds_read_b128 if possible.
-    if (Subtarget->useDS128(EnableDS128) && Load->getAlignment() >= 16 &&
+    if (Subtarget->useDS128() && Load->getAlignment() >= 16 &&
         MemVT.getStoreSize() == 16)
       return SDValue();
 
@@ -5703,7 +5698,7 @@
     }
   } else if (AS == AMDGPUASI.LOCAL_ADDRESS) {
     // Use ds_write_b128 if possible.
-    if (Subtarget->useDS128(EnableDS128) && Store->getAlignment() >= 16 &&
+    if (Subtarget->useDS128() && Store->getAlignment() >= 16 &&
         VT.getStoreSize() == 16)
       return SDValue();
 
diff --git a/llvm/test/CodeGen/AMDGPU/load-local-f32.ll b/llvm/test/CodeGen/AMDGPU/load-local-f32.ll
index c272271..c33c000 100644
--- a/llvm/test/CodeGen/AMDGPU/load-local-f32.ll
+++ b/llvm/test/CodeGen/AMDGPU/load-local-f32.ll
@@ -3,9 +3,9 @@
 ; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefixes=EG,FUNC %s
 
 ; Testing for ds_read/write_128
-; RUN: llc -march=amdgcn -mcpu=tahiti -amdgpu-ds128 < %s | FileCheck -check-prefixes=SI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=tonga -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=gfx900 -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tahiti -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=SI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
 
 ; FUNC-LABEL: {{^}}load_f32_local:
 ; SICIVI: s_mov_b32 m0
diff --git a/llvm/test/CodeGen/AMDGPU/load-local-f64.ll b/llvm/test/CodeGen/AMDGPU/load-local-f64.ll
index f4040db..e313b38 100644
--- a/llvm/test/CodeGen/AMDGPU/load-local-f64.ll
+++ b/llvm/test/CodeGen/AMDGPU/load-local-f64.ll
@@ -5,8 +5,8 @@
 ; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefixes=EG,FUNC %s
 
 ; Testing for ds_read_b128
-; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
 
 ; FUNC-LABEL: {{^}}local_load_f64:
 ; SICIV: s_mov_b32 m0
diff --git a/llvm/test/CodeGen/AMDGPU/load-local-i16.ll b/llvm/test/CodeGen/AMDGPU/load-local-i16.ll
index 83cf85b..42beb22 100644
--- a/llvm/test/CodeGen/AMDGPU/load-local-i16.ll
+++ b/llvm/test/CodeGen/AMDGPU/load-local-i16.ll
@@ -4,8 +4,8 @@
 ; RUN: llc -march=r600 -mcpu=redwood -verify-machineinstrs < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
 
 ; Testing for ds_read/write_b128
-; RUN: llc -march=amdgcn -mcpu=tonga -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=gfx900 -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
 
 ; FUNC-LABEL: {{^}}local_load_i16:
 ; GFX9-NOT: m0
diff --git a/llvm/test/CodeGen/AMDGPU/load-local-i32.ll b/llvm/test/CodeGen/AMDGPU/load-local-i32.ll
index 2d0e989..fd2a739 100644
--- a/llvm/test/CodeGen/AMDGPU/load-local-i32.ll
+++ b/llvm/test/CodeGen/AMDGPU/load-local-i32.ll
@@ -4,9 +4,9 @@
 ; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
 
 ; Testing for ds_read/write_128
-; RUN: llc -march=amdgcn -mcpu=tahiti -amdgpu-ds128 < %s | FileCheck -check-prefixes=SI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=tonga -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=gfx900 -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tahiti -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=SI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
 
 ; FUNC-LABEL: {{^}}local_load_i32:
 ; GCN-NOT: s_wqm_b64
diff --git a/llvm/test/CodeGen/AMDGPU/load-local-i64.ll b/llvm/test/CodeGen/AMDGPU/load-local-i64.ll
index 697f474..d91c3b5 100644
--- a/llvm/test/CodeGen/AMDGPU/load-local-i64.ll
+++ b/llvm/test/CodeGen/AMDGPU/load-local-i64.ll
@@ -5,8 +5,8 @@
 ; RUN: llc -march=r600 -mcpu=redwood < %s | FileCheck -check-prefixes=EG,FUNC %s
 
 ; Testing for ds_read/write_b128
-; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -verify-machineinstrs -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
 
 ; FUNC-LABEL: {{^}}local_load_i64:
 ; SICIVI: s_mov_b32 m0
diff --git a/llvm/test/CodeGen/AMDGPU/load-local-i8.ll b/llvm/test/CodeGen/AMDGPU/load-local-i8.ll
index 898d35d..81e5ceb 100644
--- a/llvm/test/CodeGen/AMDGPU/load-local-i8.ll
+++ b/llvm/test/CodeGen/AMDGPU/load-local-i8.ll
@@ -4,8 +4,8 @@
 ; RUN: llc -march=r600 -mtriple=r600---amdgiz -mcpu=redwood -verify-machineinstrs < %s | FileCheck -check-prefix=EG -check-prefix=FUNC %s
 
 ; Testing for ds_read/write_b128
-; RUN: llc -march=amdgcn -mcpu=tonga -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
-; RUN: llc -march=amdgcn -mcpu=gfx900 -amdgpu-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
+; RUN: llc -march=amdgcn -mcpu=gfx900 -mattr=+enable-ds128 < %s | FileCheck -check-prefixes=CIVI,FUNC %s
 
 ; FUNC-LABEL: {{^}}local_load_i8:
 ; GCN-NOT: s_wqm_b64
diff --git a/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll b/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll
index 5eb3b25..19fc44b 100644
--- a/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll
+++ b/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/merge-stores.ll
@@ -504,7 +504,8 @@
 }
 
 ; CHECK-LABEL: @merge_local_store_4_constants_i32
-; CHECK: store <4 x i32> <i32 1234, i32 123, i32 456, i32 333>, <4 x i32> addrspace(3)*
+; CHECK: store <2 x i32> <i32 456, i32 333>, <2 x i32> addrspace(3)*
+; CHECK: store <2 x i32> <i32 1234, i32 123>, <2 x i32> addrspace(3)*
 define amdgpu_kernel void @merge_local_store_4_constants_i32(i32 addrspace(3)* %out) #0 {
   %out.gep.1 = getelementptr i32, i32 addrspace(3)* %out, i32 1
   %out.gep.2 = getelementptr i32, i32 addrspace(3)* %out, i32 2
diff --git a/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/multiple_tails.ll b/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/multiple_tails.ll
index b684ca8..8a78f3d 100644
--- a/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/multiple_tails.ll
+++ b/llvm/test/Transforms/LoadStoreVectorizer/AMDGPU/multiple_tails.ll
@@ -29,10 +29,11 @@
 ; longest chain vectorized
 
 ; CHECK-LABEL: @interleave_get_longest
-; CHECK: load <4 x i32>
+; CHECK: load <2 x i32>
 ; CHECK: load i32
 ; CHECK: store <2 x i32> zeroinitializer
 ; CHECK: load i32
+; CHECK: load <2 x i32>
 ; CHECK: load i32
 ; CHECK: load i32