AMDGPU: Support commuting register and global operand

Author: arsenm

llvm/lib/Target/AMDGPU/SIInstrInfo.cpp

@@ -1857,7 +1857,10 @@ static MachineInstr *swapRegAndNonRegOperand(MachineInstr &MI,
     RegOp.ChangeToImmediate(NonRegOp.getImm());
   else if (NonRegOp.isFI())
     RegOp.ChangeToFrameIndex(NonRegOp.getIndex());
-  else
+  else if (NonRegOp.isGlobal()) {
+    RegOp.ChangeToGA(NonRegOp.getGlobal(), NonRegOp.getOffset(),
+                     NonRegOp.getTargetFlags());
+  } else
     return nullptr;
 
   // Make sure we don't reinterpret a subreg index in the target flags.

llvm/test/CodeGen/AMDGPU/lds-relocs.ll

@@ -35,7 +35,7 @@
 ; GCN: v_mov_b32_e32 v1, lds.external@abs32@lo ; encoding: [0xff,0x02,0x02,0x7e,A,A,A,A]
 ; GCN-NEXT:              ; fixup A - offset: 4, value: lds.external@abs32@lo, kind: FK_Data_4{{$}}
 ;
-; GCN: s_add_i32 s0, lds.defined@abs32@lo, s0 ; encoding: [0xff,0x00,0x00,0x81,A,A,A,A]
+; GCN: s_add_i32 s0, s0, lds.defined@abs32@lo ; encoding: [0x00,0xff,0x00,0x81,A,A,A,A]
 ; GCN-NEXT:          ; fixup A - offset: 4, value: lds.defined@abs32@lo, kind: FK_Data_4{{$}}
 ;
 ; GCN: .globl lds.external

llvm/test/CodeGen/AMDGPU/machine-cse-commute-target-flags.mir

@@ -5,7 +5,11 @@
   define void @commute_instruction_subreg_target_flag() { ret void }
   define void @commute_target_flag_frame_index() { ret void }
   define void @commute_target_flag_global() { ret void }
+  define void @commute_target_flag_global_offset() { ret void }
+  define void @commute_target_flag_global_offset_mismatch() { ret void }
+
   declare void @func()
+  @gv = external addrspace(1) global i32
 
 ...
 
@@ -64,11 +68,49 @@ body:             |
     ; CHECK: liveins: $sgpr0_sgpr1
     ; CHECK: [[COPY:%[0-9]+]]:sreg_64 = COPY $sgpr0_sgpr1
     ; CHECK: [[S_ADD_U32_:%[0-9]+]]:sreg_32 = S_ADD_U32 [[COPY]].sub0, target-flags(amdgpu-rel32-lo) @func, implicit-def dead $scc
-    ; CHECK: [[S_ADD_U32_1:%[0-9]+]]:sreg_32 = S_ADD_U32 target-flags(amdgpu-rel32-lo) @func, [[COPY]].sub0, implicit-def dead $scc
-    ; CHECK: S_ENDPGM 0, implicit [[S_ADD_U32_]], implicit [[S_ADD_U32_1]]
+    ; CHECK: S_ENDPGM 0, implicit [[S_ADD_U32_]], implicit [[S_ADD_U32_]]
     %0:sreg_64 = COPY $sgpr0_sgpr1
     %1:sreg_32 = S_ADD_U32 %0.sub0, target-flags(amdgpu-rel32-lo) @func, implicit-def dead $scc
     %2:sreg_32 = S_ADD_U32 target-flags(amdgpu-rel32-lo) @func, %0.sub0, implicit-def dead $scc
     S_ENDPGM 0, implicit %1, implicit %2
 
 ...
+
+---
+name: commute_target_flag_global_offset
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+
+    ; CHECK-LABEL: name: commute_target_flag_global_offset
+    ; CHECK: liveins: $sgpr0_sgpr1
+    ; CHECK: [[COPY:%[0-9]+]]:sreg_64 = COPY $sgpr0_sgpr1
+    ; CHECK: [[S_ADD_U32_:%[0-9]+]]:sreg_32 = S_ADD_U32 [[COPY]].sub0, target-flags(amdgpu-rel32-lo) @gv + 4, implicit-def dead $scc
+    ; CHECK: S_ENDPGM 0, implicit [[S_ADD_U32_]], implicit [[S_ADD_U32_]]
+    %0:sreg_64 = COPY $sgpr0_sgpr1
+    %1:sreg_32 = S_ADD_U32 %0.sub0, target-flags(amdgpu-rel32-lo) @gv + 4, implicit-def dead $scc
+    %2:sreg_32 = S_ADD_U32 target-flags(amdgpu-rel32-lo) @gv + 4, %0.sub0, implicit-def dead $scc
+    S_ENDPGM 0, implicit %1, implicit %2
+
+...
+
+---
+name: commute_target_flag_global_offset_mismatch
+tracksRegLiveness: true
+body:             |
+  bb.0:
+    liveins: $sgpr0_sgpr1
+
+    ; CHECK-LABEL: name: commute_target_flag_global_offset_mismatch
+    ; CHECK: liveins: $sgpr0_sgpr1
+    ; CHECK: [[COPY:%[0-9]+]]:sreg_64 = COPY $sgpr0_sgpr1
+    ; CHECK: [[S_ADD_U32_:%[0-9]+]]:sreg_32 = S_ADD_U32 [[COPY]].sub0, target-flags(amdgpu-rel32-lo) @gv + 4, implicit-def dead $scc
+    ; CHECK: [[S_ADD_U32_1:%[0-9]+]]:sreg_32 = S_ADD_U32 target-flags(amdgpu-rel32-lo) @gv + 8, [[COPY]].sub0, implicit-def dead $scc
+    ; CHECK: S_ENDPGM 0, implicit [[S_ADD_U32_]], implicit [[S_ADD_U32_1]]
+    %0:sreg_64 = COPY $sgpr0_sgpr1
+    %1:sreg_32 = S_ADD_U32 %0.sub0, target-flags(amdgpu-rel32-lo) @gv + 4, implicit-def dead $scc
+    %2:sreg_32 = S_ADD_U32 target-flags(amdgpu-rel32-lo) @gv + 8, %0.sub0, implicit-def dead $scc
+    S_ENDPGM 0, implicit %1, implicit %2
+
+...