[PATCH] AMDGPU/SI: select S_ABS_I32 when possible (v2)

Marek Olšák via llvm-commits llvm-commits at lists.llvm.org
Thu Oct 29 08:44:05 PDT 2015


From: Marek Olšák <marek.olsak at amd.com>

v2: added more tests, moved the SALU->VALU conversion to a separate function

It looks like it's not possible to get subregisters in the S_ABS lowering
code, and I don't feel like guessing without testing what the correct code
would look like.
---
 lib/Target/AMDGPU/SIInstrInfo.cpp      |  29 ++++++
 lib/Target/AMDGPU/SIInstrInfo.h        |   3 +
 lib/Target/AMDGPU/SIInstructions.td    |   5 ++
 test/CodeGen/AMDGPU/llvm.AMDGPU.abs.ll |   4 +-
 test/CodeGen/AMDGPU/sminmax.ll         | 156 +++++++++++++++++++++++++++++++++
 5 files changed, 194 insertions(+), 3 deletions(-)
 create mode 100644 test/CodeGen/AMDGPU/sminmax.ll

diff --git a/lib/Target/AMDGPU/SIInstrInfo.cpp b/lib/Target/AMDGPU/SIInstrInfo.cpp
index e37a619..658336c 100644
--- a/lib/Target/AMDGPU/SIInstrInfo.cpp
+++ b/lib/Target/AMDGPU/SIInstrInfo.cpp
@@ -2317,6 +2317,11 @@ void SIInstrInfo::moveToVALU(MachineInstr &TopInst) const {
       }
       break;
 
+    case AMDGPU::S_ABS_I32:
+      lowerScalarAbs(Worklist, Inst);
+      Inst->eraseFromParent();
+      continue;
+
     case AMDGPU::S_BFE_U64:
     case AMDGPU::S_BFM_B64:
       llvm_unreachable("Moving this op to VALU not implemented");
@@ -2402,6 +2407,30 @@ const TargetRegisterClass *SIInstrInfo::getIndirectAddrRegClass() const {
   return &AMDGPU::VGPR_32RegClass;
 }
 
+void SIInstrInfo::lowerScalarAbs(SmallVectorImpl<MachineInstr *> &Worklist,
+                                 MachineInstr *Inst) const {
+  MachineBasicBlock &MBB = *Inst->getParent();
+  MachineRegisterInfo &MRI = MBB.getParent()->getRegInfo();
+  MachineBasicBlock::iterator MII = Inst;
+  DebugLoc DL = Inst->getDebugLoc();
+
+  MachineOperand &Dest = Inst->getOperand(0);
+  MachineOperand &Src = Inst->getOperand(1);
+  unsigned TmpReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+  unsigned ResultReg = MRI.createVirtualRegister(&AMDGPU::VGPR_32RegClass);
+
+  BuildMI(MBB, MII, DL, get(AMDGPU::V_SUB_I32_e32), TmpReg)
+    .addImm(0)
+    .addReg(Src.getReg());
+
+  BuildMI(MBB, MII, DL, get(AMDGPU::V_MAX_I32_e64), ResultReg)
+    .addReg(Src.getReg())
+    .addReg(TmpReg);
+
+  MRI.replaceRegWith(Dest.getReg(), ResultReg);
+  addUsersToMoveToVALUWorklist(ResultReg, MRI, Worklist);
+}
+
 void SIInstrInfo::splitScalar64BitUnaryOp(
   SmallVectorImpl<MachineInstr *> &Worklist,
   MachineInstr *Inst,
diff --git a/lib/Target/AMDGPU/SIInstrInfo.h b/lib/Target/AMDGPU/SIInstrInfo.h
index 5816bf8..149c883 100644
--- a/lib/Target/AMDGPU/SIInstrInfo.h
+++ b/lib/Target/AMDGPU/SIInstrInfo.h
@@ -41,6 +41,9 @@ private:
 
   void swapOperands(MachineBasicBlock::iterator Inst) const;
 
+  void lowerScalarAbs(SmallVectorImpl<MachineInstr *> &Worklist,
+                      MachineInstr *Inst) const;
+
   void splitScalar64BitUnaryOp(SmallVectorImpl<MachineInstr *> &Worklist,
                                MachineInstr *Inst, unsigned Opcode) const;
 
diff --git a/lib/Target/AMDGPU/SIInstructions.td b/lib/Target/AMDGPU/SIInstructions.td
index ed75b4d..9e0046b 100644
--- a/lib/Target/AMDGPU/SIInstructions.td
+++ b/lib/Target/AMDGPU/SIInstructions.td
@@ -2177,6 +2177,11 @@ def : Pat <
      (S_MOV_B32 0), sub1))
 >;
 
+def : Pat <
+  (i32 (smax i32:$x, (i32 (ineg i32:$x)))),
+  (S_ABS_I32 $x)
+>;
+
 //===----------------------------------------------------------------------===//
 // SOP2 Patterns
 //===----------------------------------------------------------------------===//
diff --git a/test/CodeGen/AMDGPU/llvm.AMDGPU.abs.ll b/test/CodeGen/AMDGPU/llvm.AMDGPU.abs.ll
index 8bf094b..ca8ddba 100644
--- a/test/CodeGen/AMDGPU/llvm.AMDGPU.abs.ll
+++ b/test/CodeGen/AMDGPU/llvm.AMDGPU.abs.ll
@@ -8,9 +8,7 @@ declare i32 @llvm.AMDGPU.abs(i32) nounwind readnone
 declare i32 @llvm.AMDIL.abs.i32(i32) nounwind readnone
 
 ; FUNC-LABEL: {{^}}s_abs_i32:
-; SI: s_sub_i32
-; SI: s_max_i32
-; SI: s_endpgm
+; SI: s_abs_i32
 
 ; EG: SUB_INT
 ; EG: MAX_INT
diff --git a/test/CodeGen/AMDGPU/sminmax.ll b/test/CodeGen/AMDGPU/sminmax.ll
new file mode 100644
index 0000000..3dd49aa
--- /dev/null
+++ b/test/CodeGen/AMDGPU/sminmax.ll
@@ -0,0 +1,156 @@
+; RUN: llc -march=amdgcn -mcpu=verde -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=FUNC %s
+; RUN: llc -march=amdgcn -mcpu=tonga -verify-machineinstrs < %s | FileCheck -check-prefix=GCN -check-prefix=FUNC %s
+
+; FUNC-LABEL: {{^}}s_abs_i32:
+; GCN: s_abs_i32
+; GCN: s_add_i32
+define void @s_abs_i32(i32 addrspace(1)* %out, i32 %val) nounwind {
+  %neg = sub i32 0, %val
+  %cond = icmp sgt i32 %val, %neg
+  %res = select i1 %cond, i32 %val, i32 %neg
+  %res2 = add i32 %res, 2
+  store i32 %res2, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: {{^}}v_abs_i32:
+; GCN: v_sub_i32_e32 [[NEG:v[0-9]+]], vcc, 0, [[SRC:v[0-9]+]]
+; GCN: v_max_i32_e32 {{v[0-9]+}}, [[NEG]], [[SRC]]
+; GCN: v_add_i32
+define void @v_abs_i32(i32 addrspace(1)* %out, i32 addrspace(1)* %src) nounwind {
+  %val = load i32, i32 addrspace(1)* %src, align 4
+  %neg = sub i32 0, %val
+  %cond = icmp sgt i32 %val, %neg
+  %res = select i1 %cond, i32 %val, i32 %neg
+  %res2 = add i32 %res, 2
+  store i32 %res2, i32 addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: {{^}}s_abs_v2i32:
+; TODO: this should use s_abs_i32
+; GCNX: s_abs_i32
+; GCNX: s_abs_i32
+; GCN: s_sub
+; GCN: s_sub
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN: v_add_i32
+; GCN: v_add_i32
+define void @s_abs_v2i32(<2 x i32> addrspace(1)* %out, <2 x i32> %val) nounwind {
+  %z0 = insertelement <2 x i32> undef, i32 0, i32 0
+  %z1 = insertelement <2 x i32> %z0, i32 0, i32 1
+  %t0 = insertelement <2 x i32> undef, i32 2, i32 0
+  %t1 = insertelement <2 x i32> %t0, i32 2, i32 1
+  %neg = sub <2 x i32> %z1, %val
+  %cond = icmp sgt <2 x i32> %val, %neg
+  %res = select <2 x i1> %cond, <2 x i32> %val, <2 x i32> %neg
+  %res2 = add <2 x i32> %res, %t1
+  store <2 x i32> %res2, <2 x i32> addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: {{^}}v_abs_v2i32:
+; GCN: v_sub_i32_e32 [[NEG0:v[0-9]+]], vcc, 0, [[SRC0:v[0-9]+]]
+; GCN: v_sub_i32_e32 [[NEG1:v[0-9]+]], vcc, 0, [[SRC1:v[0-9]+]]
+; TODO: this should use v_max_i32
+; GCNX: v_max_i32_e32 {{v[0-9]+}}, [[NEG0]], [[SRC0]]
+; GCNX: v_max_i32_e32 {{v[0-9]+}}, [[NEG1]], [[SRC1]]
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN: v_add_i32
+; GCN: v_add_i32
+define void @v_abs_v2i32(<2 x i32> addrspace(1)* %out, <2 x i32> addrspace(1)* %src) nounwind {
+  %z0 = insertelement <2 x i32> undef, i32 0, i32 0
+  %z1 = insertelement <2 x i32> %z0, i32 0, i32 1
+  %t0 = insertelement <2 x i32> undef, i32 2, i32 0
+  %t1 = insertelement <2 x i32> %t0, i32 2, i32 1
+  %val = load <2 x i32>, <2 x i32> addrspace(1)* %src, align 4
+  %neg = sub <2 x i32> %z1, %val
+  %cond = icmp sgt <2 x i32> %val, %neg
+  %res = select <2 x i1> %cond, <2 x i32> %val, <2 x i32> %neg
+  %res2 = add <2 x i32> %res, %t1
+  store <2 x i32> %res2, <2 x i32> addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: {{^}}s_abs_v4i32:
+; TODO: this should use s_abs_i32
+; GCNX: s_abs_i32
+; GCNX: s_abs_i32
+; GCNX: s_abs_i32
+; GCNX: s_abs_i32
+; GCN: s_sub
+; GCN: s_sub
+; GCN: s_sub
+; GCN: s_sub
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN: v_add_i32
+; GCN: v_add_i32
+define void @s_abs_v4i32(<4 x i32> addrspace(1)* %out, <4 x i32> %val) nounwind {
+  %z0 = insertelement <4 x i32> undef, i32 0, i32 0
+  %z1 = insertelement <4 x i32> %z0, i32 0, i32 1
+  %z2 = insertelement <4 x i32> %z1, i32 0, i32 2
+  %z3 = insertelement <4 x i32> %z2, i32 0, i32 3
+  %t0 = insertelement <4 x i32> undef, i32 2, i32 0
+  %t1 = insertelement <4 x i32> %t0, i32 2, i32 1
+  %t2 = insertelement <4 x i32> %t1, i32 2, i32 2
+  %t3 = insertelement <4 x i32> %t2, i32 2, i32 3
+  %neg = sub <4 x i32> %z3, %val
+  %cond = icmp sgt <4 x i32> %val, %neg
+  %res = select <4 x i1> %cond, <4 x i32> %val, <4 x i32> %neg
+  %res2 = add <4 x i32> %res, %t3
+  store <4 x i32> %res2, <4 x i32> addrspace(1)* %out, align 4
+  ret void
+}
+
+; FUNC-LABEL: {{^}}v_abs_v4i32:
+; GCN: v_sub_i32_e32 [[NEG0:v[0-9]+]], vcc, 0, [[SRC0:v[0-9]+]]
+; GCN: v_sub_i32_e32 [[NEG1:v[0-9]+]], vcc, 0, [[SRC1:v[0-9]+]]
+; GCN: v_sub_i32_e32 [[NEG2:v[0-9]+]], vcc, 0, [[SRC2:v[0-9]+]]
+; GCN: v_sub_i32_e32 [[NEG3:v[0-9]+]], vcc, 0, [[SRC3:v[0-9]+]]
+; TODO: this should use v_max_i32
+; GCNX: v_max_i32_e32 {{v[0-9]+}}, [[NEG0]], [[SRC0]]
+; GCNX: v_max_i32_e32 {{v[0-9]+}}, [[NEG1]], [[SRC1]]
+; GCNX: v_max_i32_e32 {{v[0-9]+}}, [[NEG2]], [[SRC2]]
+; GCNX: v_max_i32_e32 {{v[0-9]+}}, [[NEG3]], [[SRC3]]
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cmp_gt
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN-DAG: v_cndmask_b32
+; GCN: v_add_i32
+; GCN: v_add_i32
+; GCN: v_add_i32
+; GCN: v_add_i32
+define void @v_abs_v4i32(<4 x i32> addrspace(1)* %out, <4 x i32> addrspace(1)* %src) nounwind {
+  %z0 = insertelement <4 x i32> undef, i32 0, i32 0
+  %z1 = insertelement <4 x i32> %z0, i32 0, i32 1
+  %z2 = insertelement <4 x i32> %z1, i32 0, i32 2
+  %z3 = insertelement <4 x i32> %z2, i32 0, i32 3
+  %t0 = insertelement <4 x i32> undef, i32 2, i32 0
+  %t1 = insertelement <4 x i32> %t0, i32 2, i32 1
+  %t2 = insertelement <4 x i32> %t1, i32 2, i32 2
+  %t3 = insertelement <4 x i32> %t2, i32 2, i32 3
+  %val = load <4 x i32>, <4 x i32> addrspace(1)* %src, align 4
+  %neg = sub <4 x i32> %z3, %val
+  %cond = icmp sgt <4 x i32> %val, %neg
+  %res = select <4 x i1> %cond, <4 x i32> %val, <4 x i32> %neg
+  %res2 = add <4 x i32> %res, %t3
+  store <4 x i32> %res2, <4 x i32> addrspace(1)* %out, align 4
+  ret void
+}
-- 
2.1.4



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