xref: /freebsd/contrib/llvm-project/llvm/lib/Target/NVPTX/NVVMIntrRange.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 //===- NVVMIntrRange.cpp - Set range attributes for NVVM intrinsics -------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This pass adds appropriate range attributes for calls to NVVM
10 // intrinsics that return a limited range of values.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "NVPTX.h"
15 #include "NVPTXUtilities.h"
16 #include "llvm/IR/InstIterator.h"
17 #include "llvm/IR/Instructions.h"
18 #include "llvm/IR/IntrinsicInst.h"
19 #include "llvm/IR/Intrinsics.h"
20 #include "llvm/IR/IntrinsicsNVPTX.h"
21 #include "llvm/IR/PassManager.h"
22 #include "llvm/Support/CommandLine.h"
23 #include <cstdint>
24 
25 using namespace llvm;
26 
27 #define DEBUG_TYPE "nvvm-intr-range"
28 
29 namespace llvm { void initializeNVVMIntrRangePass(PassRegistry &); }
30 
31 namespace {
32 class NVVMIntrRange : public FunctionPass {
33 public:
34   static char ID;
NVVMIntrRange()35   NVVMIntrRange() : FunctionPass(ID) {
36 
37     initializeNVVMIntrRangePass(*PassRegistry::getPassRegistry());
38   }
39 
40   bool runOnFunction(Function &) override;
41 };
42 } // namespace
43 
createNVVMIntrRangePass()44 FunctionPass *llvm::createNVVMIntrRangePass() { return new NVVMIntrRange(); }
45 
46 char NVVMIntrRange::ID = 0;
47 INITIALIZE_PASS(NVVMIntrRange, "nvvm-intr-range",
48                 "Add !range metadata to NVVM intrinsics.", false, false)
49 
50 // Adds the passed-in [Low,High) range information as metadata to the
51 // passed-in call instruction.
addRangeAttr(uint64_t Low,uint64_t High,IntrinsicInst * II)52 static bool addRangeAttr(uint64_t Low, uint64_t High, IntrinsicInst *II) {
53   if (II->getMetadata(LLVMContext::MD_range))
54     return false;
55 
56   const uint64_t BitWidth = II->getType()->getIntegerBitWidth();
57   ConstantRange Range(APInt(BitWidth, Low), APInt(BitWidth, High));
58 
59   if (auto CurrentRange = II->getRange())
60     Range = Range.intersectWith(CurrentRange.value());
61 
62   II->addRangeRetAttr(Range);
63   return true;
64 }
65 
runNVVMIntrRange(Function & F)66 static bool runNVVMIntrRange(Function &F) {
67   struct {
68     unsigned x, y, z;
69   } MaxBlockSize, MaxGridSize;
70 
71   const unsigned MetadataNTID = getReqNTID(F).value_or(
72       getMaxNTID(F).value_or(std::numeric_limits<unsigned>::max()));
73 
74   MaxBlockSize.x = std::min(1024u, MetadataNTID);
75   MaxBlockSize.y = std::min(1024u, MetadataNTID);
76   MaxBlockSize.z = std::min(64u, MetadataNTID);
77 
78   MaxGridSize.x = 0x7fffffff;
79   MaxGridSize.y = 0xffff;
80   MaxGridSize.z = 0xffff;
81 
82   // Go through the calls in this function.
83   bool Changed = false;
84   for (Instruction &I : instructions(F)) {
85     IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
86     if (!II)
87       continue;
88 
89     switch (II->getIntrinsicID()) {
90     // Index within block
91     case Intrinsic::nvvm_read_ptx_sreg_tid_x:
92       Changed |= addRangeAttr(0, MaxBlockSize.x, II);
93       break;
94     case Intrinsic::nvvm_read_ptx_sreg_tid_y:
95       Changed |= addRangeAttr(0, MaxBlockSize.y, II);
96       break;
97     case Intrinsic::nvvm_read_ptx_sreg_tid_z:
98       Changed |= addRangeAttr(0, MaxBlockSize.z, II);
99       break;
100 
101     // Block size
102     case Intrinsic::nvvm_read_ptx_sreg_ntid_x:
103       Changed |= addRangeAttr(1, MaxBlockSize.x + 1, II);
104       break;
105     case Intrinsic::nvvm_read_ptx_sreg_ntid_y:
106       Changed |= addRangeAttr(1, MaxBlockSize.y + 1, II);
107       break;
108     case Intrinsic::nvvm_read_ptx_sreg_ntid_z:
109       Changed |= addRangeAttr(1, MaxBlockSize.z + 1, II);
110       break;
111 
112     // Index within grid
113     case Intrinsic::nvvm_read_ptx_sreg_ctaid_x:
114       Changed |= addRangeAttr(0, MaxGridSize.x, II);
115       break;
116     case Intrinsic::nvvm_read_ptx_sreg_ctaid_y:
117       Changed |= addRangeAttr(0, MaxGridSize.y, II);
118       break;
119     case Intrinsic::nvvm_read_ptx_sreg_ctaid_z:
120       Changed |= addRangeAttr(0, MaxGridSize.z, II);
121       break;
122 
123     // Grid size
124     case Intrinsic::nvvm_read_ptx_sreg_nctaid_x:
125       Changed |= addRangeAttr(1, MaxGridSize.x + 1, II);
126       break;
127     case Intrinsic::nvvm_read_ptx_sreg_nctaid_y:
128       Changed |= addRangeAttr(1, MaxGridSize.y + 1, II);
129       break;
130     case Intrinsic::nvvm_read_ptx_sreg_nctaid_z:
131       Changed |= addRangeAttr(1, MaxGridSize.z + 1, II);
132       break;
133 
134     // warp size is constant 32.
135     case Intrinsic::nvvm_read_ptx_sreg_warpsize:
136       Changed |= addRangeAttr(32, 32 + 1, II);
137       break;
138 
139     // Lane ID is [0..warpsize)
140     case Intrinsic::nvvm_read_ptx_sreg_laneid:
141       Changed |= addRangeAttr(0, 32, II);
142       break;
143 
144     default:
145       break;
146     }
147   }
148 
149   return Changed;
150 }
151 
runOnFunction(Function & F)152 bool NVVMIntrRange::runOnFunction(Function &F) { return runNVVMIntrRange(F); }
153 
run(Function & F,FunctionAnalysisManager & AM)154 PreservedAnalyses NVVMIntrRangePass::run(Function &F,
155                                          FunctionAnalysisManager &AM) {
156   return runNVVMIntrRange(F) ? PreservedAnalyses::none()
157                              : PreservedAnalyses::all();
158 }
159