AMDGPU/SI: Add llvm.amdgcn.buffer.atomic.* intrinsics

[nhaehnle]

Summary

These intrinsics expose the BUFFER_ATOMIC_* instructions and will be used
by Mesa to implement atomics with buffer semantics. The intrinsic interface
matches that of buffer.load.format and buffer.store.format, except that the
GLC bit is not exposed (it is automatically deduced based on whether the
return value is used).

The change of hasSideEffects is required for TableGen to accept the pattern
that matches the intrinsic.

Note that there are minor conflicts with http://reviews.llvm.org/D17280,
which also touches BUFFER_ATOMIC_CMPSWAP.

[nhaehnle]

Rebase the patch on top of D18218, with adjusted/simplified signatures for
the intrinsics.

[• tstellarAMD]

I like the new signature better too.

include/llvm/IR/IntrinsicsAMDGPU.td

def int_amdgcn_buffer_store_format : Intrinsic <
   [llvm_anyfloat_ty,  // vdata(VGPR) -- can currently only select v4f32
    llvm_v4i32_ty,     // rsrc(SGPR)
    llvm_i32_ty,       // vindex(VGPR)
    llvm_i32_ty,       // offset(SGPR/VGPR/imm)
    llvm_i1_ty,        // glc(imm)
    llvm_i1_ty],       // slc(imm)
   []>;
 
+class AMDGPUBufferAtomic : Intrinsic <
+  [llvm_i32_ty],
+  [llvm_i32_ty,       // vdata(VGPR)
+   llvm_v4i32_ty,     // rsrc(SGPR)
+   llvm_i32_ty,       // vindex(VGPR)
+   llvm_i32_ty,       // offset(SGPR/VGPR/imm)
+   llvm_i1_ty],       // slc(imm)
+  []>;
+def int_amdgcn_buffer_atomic_swap : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_add : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_sub : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_smin : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_umin : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_smax : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_umax : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_and : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_or : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_xor : AMDGPUBufferAtomic;
+def int_amdgcn_buffer_atomic_cmpswap : Intrinsic<
+  [llvm_i32_ty],
+  [llvm_i32_ty,       // src(VGPR)
+   llvm_i32_ty,       // cmp(VGPR)
+   llvm_v4i32_ty,     // rsrc(SGPR)
+   llvm_i32_ty,       // vindex(VGPR)
+   llvm_i32_ty,       // offset(SGPR/VGPR/imm)
+   llvm_i1_ty],       // slc(imm)
+  []>;
+
 def int_amdgcn_read_workdim : AMDGPUReadPreloadRegisterIntrinsic <
   "__builtin_amdgcn_read_workdim">;
 
 
 def int_amdgcn_buffer_wbinvl1_sc :
   GCCBuiltin<"__builtin_amdgcn_buffer_wbinvl1_sc">,
   Intrinsic<[], [], []>;
 

lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp

static bool isIntrinsicSourceOfDivergence(const TargetIntrinsicInfo *TII,
   case Intrinsic::amdgcn_image_atomic_smax:
   case Intrinsic::amdgcn_image_atomic_umax:
   case Intrinsic::amdgcn_image_atomic_and:
   case Intrinsic::amdgcn_image_atomic_or:
   case Intrinsic::amdgcn_image_atomic_xor:
   case Intrinsic::amdgcn_image_atomic_inc:
   case Intrinsic::amdgcn_image_atomic_dec:
   case Intrinsic::amdgcn_image_atomic_cmpswap:
+  case Intrinsic::amdgcn_buffer_atomic_swap:
+  case Intrinsic::amdgcn_buffer_atomic_add:
+  case Intrinsic::amdgcn_buffer_atomic_sub:
+  case Intrinsic::amdgcn_buffer_atomic_smin:
+  case Intrinsic::amdgcn_buffer_atomic_umin:
+  case Intrinsic::amdgcn_buffer_atomic_smax:
+  case Intrinsic::amdgcn_buffer_atomic_umax:
+  case Intrinsic::amdgcn_buffer_atomic_and:
+  case Intrinsic::amdgcn_buffer_atomic_or:
+  case Intrinsic::amdgcn_buffer_atomic_xor:
+  case Intrinsic::amdgcn_buffer_atomic_cmpswap:
     return true;
   }
 
   StringRef Name = I->getCalledFunction()->getName();
   switch (TII->lookupName((const char *)Name.bytes_begin(), Name.size())) {
   default:
     return false;
   case AMDGPUIntrinsic::SI_tid:

lib/Target/AMDGPU/SIInstrInfo.td

multiclass MUBUFAtomicAddr64_m <mubuf op, string opName, dag outs, dag ins,
   let offen = 0, idxen = 0, addr64 = 1, tfe = 0 in {
     def _si : MUBUF_Real_si <op, opName, outs, ins, asm>;
   }
 
   // There is no VI version. If the pseudo is selected, it should be lowered
   // for VI appropriately.
 }
 
+multiclass MUBUFAtomicOther_m <mubuf op, string opName, dag outs, dag ins,
+                               string asm, list<dag> pattern, bit is_return> {
+
+  def "" : MUBUF_Pseudo <opName, outs, ins, pattern>,
+           AtomicNoRet<opName, is_return>;
+
+  let tfe = 0 in {
+    let addr64 = 0 in {
+      def _si : MUBUF_Real_si <op, opName, outs, ins, asm>;
+    }
+
+    def _vi : MUBUF_Real_vi <op, opName, outs, ins, asm>;
+  }
+}
+
 multiclass MUBUF_Atomic <mubuf op, string name, RegisterClass rc,
                          ValueType vt, SDPatternOperator atomic> {
 
-  let mayStore = 1, mayLoad = 1, hasPostISelHook = 1 in {
+  let mayStore = 1, mayLoad = 1, hasPostISelHook = 1, hasSideEffects = 1 in {
 
     // No return variants
     let glc = 0 in {
 
       defm _ADDR64 : MUBUFAtomicAddr64_m <
         op, name#"_addr64", (outs),
         (ins rc:$vdata, VReg_64:$vaddr, SReg_128:$srsrc,
              SCSrc_32:$soffset, mbuf_offset:$offset, slc:$slc),
         name#" $vdata, $vaddr, $srsrc, $soffset addr64"#"$offset"#"$slc", [], 0
       >;
 
       defm _OFFSET : MUBUFAtomicOffset_m <
         op, name#"_offset", (outs),
         (ins rc:$vdata, SReg_128:$srsrc, SCSrc_32:$soffset, mbuf_offset:$offset,
              slc:$slc),
         name#" $vdata, $srsrc, $soffset"#"$offset"#"$slc", [], 0
       >;
+
+      let offen = 1, idxen = 0 in {
+        defm _OFFEN : MUBUFAtomicOther_m <
+          op, name#"_offen", (outs),
+          (ins rc:$vdata, VGPR_32:$vaddr, SReg_128:$srsrc, SCSrc_32:$soffset,
+                mbuf_offset:$offset, slc:$slc),
+          name#" $vdata, $vaddr, $srsrc, $soffset offen"#"$offset"#"$slc", [], 0
+        >;
+      }
+
+      let offen = 0, idxen = 1 in {
+        defm _IDXEN : MUBUFAtomicOther_m <
+          op, name#"_idxen", (outs),
+          (ins rc:$vdata, VGPR_32:$vaddr, SReg_128:$srsrc, SCSrc_32:$soffset,
+                mbuf_offset:$offset, slc:$slc),
+          name#" $vdata, $vaddr, $srsrc, $soffset idxen"#"$offset"#"$slc", [], 0
+        >;
+      }
+
+      let offen = 1, idxen = 1 in {
+        defm _BOTHEN : MUBUFAtomicOther_m <
+          op, name#"_bothen", (outs),
+          (ins rc:$vdata, VReg_64:$vaddr, SReg_128:$srsrc, SCSrc_32:$soffset,
+                mbuf_offset:$offset, slc:$slc),
+          name#" $vdata, $vaddr, $srsrc, $soffset idxen offen"#"$offset"#"$slc",
+          [], 0
+        >;
+      }
     } // glc = 0
 
     // Variant that return values
     let glc = 1, Constraints = "$vdata = $vdata_in",
         DisableEncoding = "$vdata_in"  in {
 
       defm _RTN_ADDR64 : MUBUFAtomicAddr64_m <
         op, name#"_rtn_addr64", (outs rc:$vdata),
let glc = 1, Constraints = "$vdata = $vdata_in",
         (ins rc:$vdata_in, SReg_128:$srsrc, SCSrc_32:$soffset,
              mbuf_offset:$offset, slc:$slc),
         name#" $vdata, $srsrc, $soffset"#"$offset"#" glc$slc",
         [(set vt:$vdata,
          (atomic (MUBUFOffsetAtomic v4i32:$srsrc, i32:$soffset, i16:$offset,
                                     i1:$slc), vt:$vdata_in))], 1
       >;
 
+      let offen = 1, idxen = 0 in {
+        defm _RTN_OFFEN : MUBUFAtomicOther_m <
+          op, name#"_rtn_offen", (outs rc:$vdata),
+          (ins rc:$vdata_in, VGPR_32:$vaddr, SReg_128:$srsrc, SCSrc_32:$soffset,
+                mbuf_offset:$offset, slc:$slc),
+          name#" $vdata, $vaddr, $srsrc, $soffset offen"#"$offset"#" glc"#"$slc",
+          [], 1
+        >;
+      }
+
+      let offen = 0, idxen = 1 in {
+        defm _RTN_IDXEN : MUBUFAtomicOther_m <
+          op, name#"_rtn_idxen", (outs rc:$vdata),
+          (ins rc:$vdata_in, VGPR_32:$vaddr, SReg_128:$srsrc, SCSrc_32:$soffset,
+                mbuf_offset:$offset, slc:$slc),
+          name#" $vdata, $vaddr, $srsrc, $soffset idxen"#"$offset"#" glc"#"$slc",
+          [], 1
+        >;
+      }
+
+      let offen = 1, idxen = 1 in {
+        defm _RTN_BOTHEN : MUBUFAtomicOther_m <
+          op, name#"_rtn_bothen", (outs rc:$vdata),
+          (ins rc:$vdata_in, VReg_64:$vaddr, SReg_128:$srsrc, SCSrc_32:$soffset,
+                mbuf_offset:$offset, slc:$slc),
+          name#" $vdata, $vaddr, $srsrc, $soffset idxen offen"#"$offset"#" glc"#"$slc",
+          [], 1
+        >;
+      }
     } // glc = 1
 
   } // mayStore = 1, mayLoad = 1, hasPostISelHook = 1
 }
 
 // FIXME: tfe can't be an operand because it requires a separate
 // opcode because it needs an N+1 register class dest register.
 multiclass MUBUF_Load_Helper <mubuf op, string name, RegisterClass regClass,

lib/Target/AMDGPU/SIInstructions.td

 
 defm BUFFER_STORE_DWORDX4 : MUBUF_Store_Helper <
   mubuf<0x1e, 0x1f>, "buffer_store_dwordx4", VReg_128, v4i32, global_store
 >;
 
 defm BUFFER_ATOMIC_SWAP : MUBUF_Atomic <
   mubuf<0x30, 0x40>, "buffer_atomic_swap", VGPR_32, i32, atomic_swap_global
 >;
-//def BUFFER_ATOMIC_CMPSWAP : MUBUF_ <mubuf<0x31, 0x41>, "buffer_atomic_cmpswap", []>;
+defm BUFFER_ATOMIC_CMPSWAP : MUBUF_Atomic <
+  mubuf<0x31, 0x41>, "buffer_atomic_cmpswap", VReg_64, v2i32, null_frag
+>;
 defm BUFFER_ATOMIC_ADD : MUBUF_Atomic <
   mubuf<0x32, 0x42>, "buffer_atomic_add", VGPR_32, i32, atomic_add_global
 >;
 defm BUFFER_ATOMIC_SUB : MUBUF_Atomic <
   mubuf<0x33, 0x43>, "buffer_atomic_sub", VGPR_32, i32, atomic_sub_global
 >;
 //def BUFFER_ATOMIC_RSUB : MUBUF_ <mubuf<0x34>, "buffer_atomic_rsub", []>; // isn't on CI & VI
 defm BUFFER_ATOMIC_SMIN : MUBUF_Atomic <
def : Pat<
   (BUFFER_STORE_FORMAT_XYZW_BOTHEN
     $vdata,
     (REG_SEQUENCE VReg_64, $vindex, sub0, $voffset, sub1),
     $rsrc, $soffset, (as_i16imm $offset),
     (as_i1imm $glc), (as_i1imm $slc), 0)
 >;
 
 //===----------------------------------------------------------------------===//
+// buffer_atomic patterns
+//===----------------------------------------------------------------------===//
+multiclass BufferAtomicPatterns<SDPatternOperator name, string opcode> {
+  def : Pat<
+    (name i32:$vdata_in, v4i32:$rsrc, 0,
+          (MUBUFIntrinsicOffset i32:$soffset, i16:$offset),
+          imm:$slc),
+    (!cast<MUBUF>(opcode # _RTN_OFFSET) $vdata_in, $rsrc, $soffset,
+                                        (as_i16imm $offset), (as_i1imm $slc))
+  >;
+
+  def : Pat<
+    (name i32:$vdata_in, v4i32:$rsrc, i32:$vindex,
+          (MUBUFIntrinsicOffset i32:$soffset, i16:$offset),
+          imm:$slc),
+    (!cast<MUBUF>(opcode # _RTN_IDXEN) $vdata_in, $vindex, $rsrc, $soffset,
+                                       (as_i16imm $offset), (as_i1imm $slc))
+  >;
+
+  def : Pat<
+    (name i32:$vdata_in, v4i32:$rsrc, 0,
+          (MUBUFIntrinsicVOffset i32:$soffset, i16:$offset, i32:$voffset),
+          imm:$slc),
+    (!cast<MUBUF>(opcode # _RTN_OFFEN) $vdata_in, $voffset, $rsrc, $soffset,
+                                       (as_i16imm $offset), (as_i1imm $slc))
+  >;
+
+  def : Pat<
+    (name i32:$vdata_in, v4i32:$rsrc, i32:$vindex,
+          (MUBUFIntrinsicVOffset i32:$soffset, i16:$offset, i32:$voffset),
+          imm:$slc),
+    (!cast<MUBUF>(opcode # _RTN_BOTHEN)
+      $vdata_in,
+      (REG_SEQUENCE VReg_64, $vindex, sub0, $voffset, sub1),
+      $rsrc, $soffset, (as_i16imm $offset), (as_i1imm $slc))
+  >;
+}
+
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_swap, "BUFFER_ATOMIC_SWAP">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_add, "BUFFER_ATOMIC_ADD">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_sub, "BUFFER_ATOMIC_SUB">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_smin, "BUFFER_ATOMIC_SMIN">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_umin, "BUFFER_ATOMIC_UMIN">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_smax, "BUFFER_ATOMIC_SMAX">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_umax, "BUFFER_ATOMIC_UMAX">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_and, "BUFFER_ATOMIC_AND">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_or, "BUFFER_ATOMIC_OR">;
+defm : BufferAtomicPatterns<int_amdgcn_buffer_atomic_xor, "BUFFER_ATOMIC_XOR">;
+
+def : Pat<
+  (int_amdgcn_buffer_atomic_cmpswap
+      i32:$data, i32:$cmp, v4i32:$rsrc, 0,
+      (MUBUFIntrinsicOffset i32:$soffset, i16:$offset),
+      imm:$slc),
+  (EXTRACT_SUBREG
+    (BUFFER_ATOMIC_CMPSWAP_RTN_OFFSET
+      (REG_SEQUENCE VReg_64, $data, sub0, $cmp, sub1),
+      $rsrc, $soffset, (as_i16imm $offset), (as_i1imm $slc)),
+    sub0)
+>;
+
+def : Pat<
+  (int_amdgcn_buffer_atomic_cmpswap
+      i32:$data, i32:$cmp, v4i32:$rsrc, i32:$vindex,
+      (MUBUFIntrinsicOffset i32:$soffset, i16:$offset),
+      imm:$slc),
+  (EXTRACT_SUBREG
+    (BUFFER_ATOMIC_CMPSWAP_RTN_IDXEN
+      (REG_SEQUENCE VReg_64, $data, sub0, $cmp, sub1),
+      $vindex, $rsrc, $soffset, (as_i16imm $offset), (as_i1imm $slc)),
+    sub0)
+>;
+
+def : Pat<
+  (int_amdgcn_buffer_atomic_cmpswap
+      i32:$data, i32:$cmp, v4i32:$rsrc, 0,
+      (MUBUFIntrinsicVOffset i32:$soffset, i16:$offset, i32:$voffset),
+      imm:$slc),
+  (EXTRACT_SUBREG
+    (BUFFER_ATOMIC_CMPSWAP_RTN_OFFEN
+      (REG_SEQUENCE VReg_64, $data, sub0, $cmp, sub1),
+      $voffset, $rsrc, $soffset, (as_i16imm $offset), (as_i1imm $slc)),
+    sub0)
+>;
+
+def : Pat<
+  (int_amdgcn_buffer_atomic_cmpswap
+      i32:$data, i32:$cmp, v4i32:$rsrc, i32:$vindex,
+      (MUBUFIntrinsicVOffset i32:$soffset, i16:$offset, i32:$voffset),
+      imm:$slc),
+  (EXTRACT_SUBREG
+    (BUFFER_ATOMIC_CMPSWAP_RTN_BOTHEN
+      (REG_SEQUENCE VReg_64, $data, sub0, $cmp, sub1),
+      (REG_SEQUENCE VReg_64, $vindex, sub0, $voffset, sub1),
+      $rsrc, $soffset, (as_i16imm $offset), (as_i1imm $slc)),
+    sub0)
+>;
+
+
+//===----------------------------------------------------------------------===//
 // S_GETREG_B32 Intrinsic Pattern.
 //===----------------------------------------------------------------------===//
 def : Pat <
   (int_amdgcn_s_getreg imm:$simm16),
   (S_GETREG_B32 (as_i16imm $simm16))
 >;
 
 //===----------------------------------------------------------------------===//

test/Analysis/DivergenceAnalysis/AMDGPU/llvm.amdgcn.buffer.atomic.ll

+;RUN: opt -mtriple=amdgcn-mesa-mesa3d -analyze -divergence %s | FileCheck %s
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.swap(
+define float @buffer_atomic_swap(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.add(
+define float @buffer_atomic_add(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.add(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.sub(
+define float @buffer_atomic_sub(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.sub(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.smin(
+define float @buffer_atomic_smin(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.smin(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.umin(
+define float @buffer_atomic_umin(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.umin(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.smax(
+define float @buffer_atomic_smax(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.smax(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.umax(
+define float @buffer_atomic_umax(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.umax(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.and(
+define float @buffer_atomic_and(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.and(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.or(
+define float @buffer_atomic_or(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.or(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.xor(
+define float @buffer_atomic_xor(<4 x i32> inreg %rsrc, i32 inreg %data) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.xor(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+;CHECK: DIVERGENT: %orig = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(
+define float @buffer_atomic_cmpswap(<4 x i32> inreg %rsrc, i32 inreg %data, i32 inreg %cmp) #0 {
+main_body:
+  %orig = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %data, i32 %cmp, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %r = bitcast i32 %orig to float
+  ret float %r
+}
+
+declare i32 @llvm.amdgcn.buffer.atomic.swap(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.add(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.sub(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.smin(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.umin(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.smax(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.umax(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.and(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.or(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.xor(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32, i32, <4 x i32>, i32, i32, i1) #1
+
+attributes #0 = { "ShaderType"="0" }
+attributes #1 = { nounwind }

test/CodeGen/AMDGPU/llvm.amdgcn.buffer.atomic.ll

+;RUN: llc < %s -march=amdgcn -mcpu=verde -verify-machineinstrs | FileCheck %s
+;RUN: llc < %s -march=amdgcn -mcpu=tonga -verify-machineinstrs | FileCheck %s
+
+;CHECK-LABEL: {{^}}test1:
+;CHECK: buffer_atomic_swap v0, s[0:3], 0 glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_swap v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_swap v0, v2, s[0:3], 0 offen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_swap v0, v[1:2], s[0:3], 0 idxen offen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_swap v0, v2, s[0:3], 0 offen offset:42 glc
+;CHECK-DAG: s_waitcnt vmcnt(0)
+;CHECK-DAG: s_movk_i32 [[SOFS:s[0-9]+]], 0x1000
+;CHECK: buffer_atomic_swap v0, s[0:3], [[SOFS]] glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_swap v0, s[0:3], 0{{$}}
+define float @test1(<4 x i32> inreg %rsrc, i32 %data, i32 %vindex, i32 %voffset) #0 {
+main_body:
+  %o1 = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %data, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %o2 = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %o1, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %o3 = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %o2, <4 x i32> %rsrc, i32 0, i32 %voffset, i1 0)
+  %o4 = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %o3, <4 x i32> %rsrc, i32 %vindex, i32 %voffset, i1 0)
+  %ofs.5 = add i32 %voffset, 42
+  %o5 = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %o4, <4 x i32> %rsrc, i32 0, i32 %ofs.5, i1 0)
+  %o6 = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %o5, <4 x i32> %rsrc, i32 0, i32 4096, i1 0)
+  %unused = call i32 @llvm.amdgcn.buffer.atomic.swap(i32 %o6, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %out = bitcast i32 %o6 to float
+  ret float %out
+}
+
+;CHECK-LABEL: {{^}}test2:
+;CHECK: buffer_atomic_add v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_sub v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_smin v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_umin v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_smax v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_umax v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_and v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_or v0, v1, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_xor v0, v1, s[0:3], 0 idxen glc
+define float @test2(<4 x i32> inreg %rsrc, i32 %data, i32 %vindex) #0 {
+main_body:
+  %t1 = call i32 @llvm.amdgcn.buffer.atomic.add(i32 %data, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t2 = call i32 @llvm.amdgcn.buffer.atomic.sub(i32 %t1, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t3 = call i32 @llvm.amdgcn.buffer.atomic.smin(i32 %t2, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t4 = call i32 @llvm.amdgcn.buffer.atomic.umin(i32 %t3, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t5 = call i32 @llvm.amdgcn.buffer.atomic.smax(i32 %t4, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t6 = call i32 @llvm.amdgcn.buffer.atomic.umax(i32 %t5, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t7 = call i32 @llvm.amdgcn.buffer.atomic.and(i32 %t6, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t8 = call i32 @llvm.amdgcn.buffer.atomic.or(i32 %t7, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %t9 = call i32 @llvm.amdgcn.buffer.atomic.xor(i32 %t8, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %out = bitcast i32 %t9 to float
+  ret float %out
+}
+
+; Ideally, we would teach tablegen & friends that cmpswap only modifies the
+; first vgpr. Since we don't do that yet, the register allocator will have to
+; create copies which we don't bother to track here.
+;
+;CHECK-LABEL: {{^}}test3:
+;CHECK-DAG: s_movk_i32 [[SOFS:s[0-9]+]], 0x1000
+;CHECK: buffer_atomic_cmpswap {{v\[[0-9]+:[0-9]+\]}}, s[0:3], 0 glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_cmpswap {{v\[[0-9]+:[0-9]+\]}}, v2, s[0:3], 0 idxen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_cmpswap {{v\[[0-9]+:[0-9]+\]}}, v3, s[0:3], 0 offen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_cmpswap {{v\[[0-9]+:[0-9]+\]}}, v[2:3], s[0:3], 0 idxen offen glc
+;CHECK: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_cmpswap {{v\[[0-9]+:[0-9]+\]}}, v3, s[0:3], 0 offen offset:42 glc
+;CHECK-DAG: s_waitcnt vmcnt(0)
+;CHECK: buffer_atomic_cmpswap {{v\[[0-9]+:[0-9]+\]}}, s[0:3], [[SOFS]] glc
+define float @test3(<4 x i32> inreg %rsrc, i32 %data, i32 %cmp, i32 %vindex, i32 %voffset) #0 {
+main_body:
+  %o1 = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %data, i32 %cmp, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %o2 = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %o1, i32 %cmp, <4 x i32> %rsrc, i32 %vindex, i32 0, i1 0)
+  %o3 = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %o2, i32 %cmp, <4 x i32> %rsrc, i32 0, i32 %voffset, i1 0)
+  %o4 = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %o3, i32 %cmp, <4 x i32> %rsrc, i32 %vindex, i32 %voffset, i1 0)
+  %ofs.5 = add i32 %voffset, 42
+  %o5 = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %o4, i32 %cmp, <4 x i32> %rsrc, i32 0, i32 %ofs.5, i1 0)
+  %o6 = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %o5, i32 %cmp, <4 x i32> %rsrc, i32 0, i32 4096, i1 0)
+
+; Detecting the no-return variant doesn't work right now because of how the
+; intrinsic is replaced by an instruction that feeds into an EXTRACT_SUBREG.
+; Since there probably isn't a reasonable use-case of cmpswap that discards
+; the return value, that seems okay.
+;
+;  %unused = call i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32 %o6, i32 %cmp, <4 x i32> %rsrc, i32 0, i32 0, i1 0)
+  %out = bitcast i32 %o6 to float
+  ret float %out
+}
+
+declare i32 @llvm.amdgcn.buffer.atomic.swap(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.add(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.sub(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.smin(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.umin(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.smax(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.umax(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.and(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.or(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.xor(i32, <4 x i32>, i32, i32, i1) #1
+declare i32 @llvm.amdgcn.buffer.atomic.cmpswap(i32, i32, <4 x i32>, i32, i32, i1) #1
+
+attributes #0 = { "ShaderType"="0" }
+attributes #1 = { nounwind }