AMDGPU: Do permlane16 vdst_in discard optimization in InstCombine

There's more potential value to discarding the source value earlier,
since we always know the value of the fi/bc bits.

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index f463c5f..f3019fe 100644 (file)
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -3959,6 +3959,21 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     II->setOperand(0, UndefValue::get(Old->getType()));
     return II;
   }
+  case Intrinsic::amdgcn_permlane16:
+  case Intrinsic::amdgcn_permlanex16: {
+    // Discard vdst_in if it's not going to be read.
+    Value *VDstIn = II->getArgOperand(0);
+   if (isa<UndefValue>(VDstIn))
+     break;
+
+    ConstantInt *FetchInvalid = cast<ConstantInt>(II->getArgOperand(4));
+    ConstantInt *BoundCtrl = cast<ConstantInt>(II->getArgOperand(5));
+    if (!FetchInvalid->getZExtValue() && !BoundCtrl->getZExtValue())
+      break;
+
+    II->setArgOperand(0, UndefValue::get(VDstIn->getType()));
+    return II;
+  }
   case Intrinsic::amdgcn_readfirstlane:
   case Intrinsic::amdgcn_readlane: {
     // A constant value is trivially uniform.

diff --git a/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll b/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
index 7c11a74..1c622a3 100644 (file)
--- a/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
+++ b/llvm/test/Transforms/InstCombine/AMDGPU/amdgcn-intrinsics.ll
@@ -2655,5 +2655,83 @@ define amdgpu_kernel void @update_dpp_undef_old(i32 addrspace(1)* %out, i32 %in1
   ret void
 }
 
-; CHECK: attributes [[CONVERGENT]] = { convergent }
 
+; --------------------------------------------------------------------
+; llvm.amdgcn.permlane16
+; --------------------------------------------------------------------
+
+declare i32 @llvm.amdgcn.permlane16(i32, i32, i32, i32, i1 immarg, i1 immarg)
+
+define amdgpu_kernel void @permlane16(i32 addrspace(1)* %out, i32 %src0, i32 %src1, i32 %src2) {
+; CHECK-LABEL: @permlane16(
+; CHECK-NEXT:    [[RES:%.*]] = call i32 @llvm.amdgcn.permlane16(i32 12345, i32 [[SRC0:%.*]], i32 [[SRC1:%.*]], i32 [[SRC2:%.*]], i1 false, i1 false)
+; CHECK-NEXT:    store i32 [[RES]], i32 addrspace(1)* [[OUT:%.*]], align 4
+; CHECK-NEXT:    ret void
+;
+  %res = call i32 @llvm.amdgcn.permlane16(i32 12345, i32 %src0, i32 %src1, i32 %src2, i1 false, i1 false)
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+define amdgpu_kernel void @permlane16_bound_ctrl(i32 addrspace(1)* %out, i32 %src0, i32 %src1, i32 %src2) {
+; CHECK-LABEL: @permlane16_bound_ctrl(
+; CHECK-NEXT:    [[RES:%.*]] = call i32 @llvm.amdgcn.permlane16(i32 undef, i32 [[SRC0:%.*]], i32 [[SRC1:%.*]], i32 [[SRC2:%.*]], i1 false, i1 true)
+; CHECK-NEXT:    store i32 [[RES]], i32 addrspace(1)* [[OUT:%.*]], align 4
+; CHECK-NEXT:    ret void
+;
+  %res = call i32 @llvm.amdgcn.permlane16(i32 12345, i32 %src0, i32 %src1, i32 %src2, i1 false, i1 true)
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+define amdgpu_kernel void @permlane16_fetch_invalid_bound_ctrl(i32 addrspace(1)* %out, i32 %src0, i32 %src1, i32 %src2) {
+; CHECK-LABEL: @permlane16_fetch_invalid_bound_ctrl(
+; CHECK-NEXT:    [[RES:%.*]] = call i32 @llvm.amdgcn.permlane16(i32 undef, i32 [[SRC0:%.*]], i32 [[SRC1:%.*]], i32 [[SRC2:%.*]], i1 true, i1 true)
+; CHECK-NEXT:    store i32 [[RES]], i32 addrspace(1)* [[OUT:%.*]], align 4
+; CHECK-NEXT:    ret void
+;
+  %res = call i32 @llvm.amdgcn.permlane16(i32 12345, i32 %src0, i32 %src1, i32 %src2, i1 true, i1 true)
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+; --------------------------------------------------------------------
+; llvm.amdgcn.permlanex16
+; --------------------------------------------------------------------
+
+declare i32 @llvm.amdgcn.permlanex16(i32, i32, i32, i32, i1 immarg, i1 immarg)
+
+define amdgpu_kernel void @permlanex16(i32 addrspace(1)* %out, i32 %src0, i32 %src1, i32 %src2) {
+; CHECK-LABEL: @permlanex16(
+; CHECK-NEXT:    [[RES:%.*]] = call i32 @llvm.amdgcn.permlanex16(i32 12345, i32 [[SRC0:%.*]], i32 [[SRC1:%.*]], i32 [[SRC2:%.*]], i1 false, i1 false)
+; CHECK-NEXT:    store i32 [[RES]], i32 addrspace(1)* [[OUT:%.*]], align 4
+; CHECK-NEXT:    ret void
+;
+  %res = call i32 @llvm.amdgcn.permlanex16(i32 12345, i32 %src0, i32 %src1, i32 %src2, i1 false, i1 false)
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+define amdgpu_kernel void @permlanex16_bound_ctrl(i32 addrspace(1)* %out, i32 %src0, i32 %src1, i32 %src2) {
+; CHECK-LABEL: @permlanex16_bound_ctrl(
+; CHECK-NEXT:    [[RES:%.*]] = call i32 @llvm.amdgcn.permlanex16(i32 undef, i32 [[SRC0:%.*]], i32 [[SRC1:%.*]], i32 [[SRC2:%.*]], i1 false, i1 true)
+; CHECK-NEXT:    store i32 [[RES]], i32 addrspace(1)* [[OUT:%.*]], align 4
+; CHECK-NEXT:    ret void
+;
+  %res = call i32 @llvm.amdgcn.permlanex16(i32 12345, i32 %src0, i32 %src1, i32 %src2, i1 false, i1 true)
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+define amdgpu_kernel void @permlanex16_fetch_invalid_bound_ctrl(i32 addrspace(1)* %out, i32 %src0, i32 %src1, i32 %src2) {
+; CHECK-LABEL: @permlanex16_fetch_invalid_bound_ctrl(
+; CHECK-NEXT:    [[RES:%.*]] = call i32 @llvm.amdgcn.permlanex16(i32 undef, i32 [[SRC0:%.*]], i32 [[SRC1:%.*]], i32 [[SRC2:%.*]], i1 true, i1 true)
+; CHECK-NEXT:    store i32 [[RES]], i32 addrspace(1)* [[OUT:%.*]], align 4
+; CHECK-NEXT:    ret void
+;
+  %res = call i32 @llvm.amdgcn.permlanex16(i32 12345, i32 %src0, i32 %src1, i32 %src2, i1 true, i1 true)
+  store i32 %res, i32 addrspace(1)* %out
+  ret void
+}
+
+; CHECK: attributes [[CONVERGENT]] = { convergent }