[amdgpu] Change LDS lowering default to hybrid

Postponed from D139433 until the bug fixed by D139874 could be resolved. Reviewed By: arsenm Differential Revision: https://reviews.llvm.org/D141852
llvm · Feb 24, 2023 · bf579a7 · bf579a7
1 parent 8e2f838
commit bf579a7
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Showing 3 changed files with 21 additions and 11 deletions.
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -1329,6 +1329,18 @@ SDValue AMDGPUTargetLowering::LowerGlobalAddress(AMDGPUMachineFunction* MFI,
   GlobalAddressSDNode *G = cast<GlobalAddressSDNode>(Op);
   const GlobalValue *GV = G->getGlobal();
 
+  if (G->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS) {
+    if (!MFI->isModuleEntryFunction()) {
+      if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV)) {
+        if (AMDGPUMachineFunction::isKnownAddressLDSGlobal(*GVar)) {
+          unsigned Offset =
+              AMDGPUMachineFunction::calculateKnownAddressOfLDSGlobal(*GVar);
+          return DAG.getConstant(Offset, SDLoc(Op), Op.getValueType());
+        }
+      }
+    }
+  }
+
   if (G->getAddressSpace() == AMDGPUAS::LOCAL_ADDRESS ||
       G->getAddressSpace() == AMDGPUAS::REGION_ADDRESS) {
     if (!MFI->isModuleEntryFunction() &&

diff --git a/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp b/llvm/lib/Target/AMDGPU/AMDGPULowerModuleLDSPass.cpp
@@ -162,7 +162,7 @@ enum class LoweringKind { module, table, kernel, hybrid };
 cl::opt<LoweringKind> LoweringKindLoc(
     "amdgpu-lower-module-lds-strategy",
     cl::desc("Specify lowering strategy for function LDS access:"), cl::Hidden,
-    cl::init(LoweringKind::module),
+    cl::init(LoweringKind::hybrid),
     cl::values(
         clEnumValN(LoweringKind::table, "table", "Lower via table lookup"),
         clEnumValN(LoweringKind::module, "module", "Lower via module struct"),

diff --git a/llvm/test/CodeGen/AMDGPU/lower-module-lds-via-hybrid.ll b/llvm/test/CodeGen/AMDGPU/lower-module-lds-via-hybrid.ll
@@ -30,13 +30,12 @@ define void @f0() {
 ; GCN-LABEL: f0:
 ; GCN:       ; %bb.0:
 ; GCN-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; GCN-NEXT:    s_mov_b64 s[0:1], s[6:7]
-; GCN-NEXT:    s_trap 2
+; GCN-NEXT:    v_mov_b32_e32 v0, 0
 ; GCN-NEXT:    s_mov_b32 m0, -1
-; GCN-NEXT:    ds_read_b32 v0, v0
+; GCN-NEXT:    ds_read_b32 v1, v0 offset:4
 ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-; GCN-NEXT:    v_add_f32_e32 v0, v0, v0
-; GCN-NEXT:    ds_write_b32 v0, v0
+; GCN-NEXT:    v_add_f32_e32 v1, v1, v1
+; GCN-NEXT:    ds_write_b32 v0, v1 offset:4
 ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
 ; GCN-NEXT:    s_setpc_b64 s[30:31]
   %ld = load float, ptr addrspace(3) @v0
@@ -120,13 +119,12 @@ define void @f3() {
 ; GCN-LABEL: f3:
 ; GCN:       ; %bb.0:
 ; GCN-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; GCN-NEXT:    s_mov_b64 s[0:1], s[6:7]
-; GCN-NEXT:    s_trap 2
+; GCN-NEXT:    v_mov_b32_e32 v0, 0
 ; GCN-NEXT:    s_mov_b32 m0, -1
-; GCN-NEXT:    ds_read_u8 v0, v0
+; GCN-NEXT:    ds_read_u8 v1, v0 offset:8
 ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
-; GCN-NEXT:    v_mul_lo_u32 v0, v0, 5
-; GCN-NEXT:    ds_write_b8 v0, v0
+; GCN-NEXT:    v_mul_lo_u32 v1, v1, 5
+; GCN-NEXT:    ds_write_b8 v0, v1 offset:8
 ; GCN-NEXT:    s_waitcnt lgkmcnt(0)
 ; GCN-NEXT:    s_setpc_b64 s[30:31]
   %ld = load i8, ptr addrspace(3) @v3