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[AMDGPU] Optimze old value of v_mov_b32_dpp 

We can eliminate old value if bound_ctrl = 1 and row_mask = bank_mask = 0xf.
This is alternative implementation working with the intrinsic in InstCombine.
Original review for past-ISel optimization: D46570.

Differential Revision: https://reviews.llvm.org/D46596

llvm-svn: 332956
This commit is contained in:
Stanislav Mekhanoshin 2018-05-22 08:04:33 +00:00
parent 7c6cd52698
commit 0e132dca53
2 changed files with 46 additions and 0 deletions
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17
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
View File

@ -3407,6 +3407,23 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
// amdgcn.kill(i1 1) is a no-op
return eraseInstFromFunction(CI);
}
case Intrinsic::amdgcn_update_dpp: {
Value *Old = II->getArgOperand(0);
auto BC = dyn_cast<ConstantInt>(II->getArgOperand(5));
auto RM = dyn_cast<ConstantInt>(II->getArgOperand(3));
auto BM = dyn_cast<ConstantInt>(II->getArgOperand(4));
if (!BC || !RM || !BM ||
BC->isZeroValue() ||
RM->getZExtValue() != 0xF ||
BM->getZExtValue() != 0xF ||
isa<UndefValue>(Old))
break;
// If bound_ctrl = 1, row mask = bank mask = 0xf we can omit old value.
II->setOperand(0, UndefValue::get(Old->getType()));
return II;
}
case Intrinsic::stackrestore: {
// If the save is right next to the restore, remove the restore. This can
// happen when variable allocas are DCE'd.

29
llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
View File

@ -1692,5 +1692,34 @@ define void @kill_true() {
ret void
}
; --------------------------------------------------------------------
; llvm.amdgcn.update.dpp.i32
; --------------------------------------------------------------------
declare i32 @llvm.amdgcn.update.dpp.i32(i32, i32, i32, i32, i32, i1)
; CHECK-LABEL: {{^}}define amdgpu_kernel void @update_dpp_no_combine(
; CHECK: @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 1, i32 1, i32 1, i1 false)
define amdgpu_kernel void @update_dpp_no_combine(i32 addrspace(1)* %out, i32 %in1, i32 %in2) {
%tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 1, i32 1, i32 1, i1 0)
store i32 %tmp0, i32 addrspace(1)* %out
ret void
}
; CHECK-LABEL: {{^}}define amdgpu_kernel void @update_dpp_drop_old(
; CHECK: @llvm.amdgcn.update.dpp.i32(i32 undef, i32 %in2, i32 3, i32 15, i32 15, i1 true)
define amdgpu_kernel void @update_dpp_drop_old(i32 addrspace(1)* %out, i32 %in1, i32 %in2) {
%tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 %in1, i32 %in2, i32 3, i32 15, i32 15, i1 1)
store i32 %tmp0, i32 addrspace(1)* %out
ret void
}
; CHECK-LABEL: {{^}}define amdgpu_kernel void @update_dpp_undef_old(
; CHECK: @llvm.amdgcn.update.dpp.i32(i32 undef, i32 %in1, i32 4, i32 15, i32 15, i1 true)
define amdgpu_kernel void @update_dpp_undef_old(i32 addrspace(1)* %out, i32 %in1) {
%tmp0 = call i32 @llvm.amdgcn.update.dpp.i32(i32 undef, i32 %in1, i32 4, i32 15, i32 15, i1 1)
store i32 %tmp0, i32 addrspace(1)* %out
ret void
}
; CHECK: attributes #5 = { convergent }