Consistently store pid, tid and probe id as int32_t

Previously, they were mostly 64-bit but had a few places where they were treated as 32-bit. This saves some memory and may marginally improve performance when pushing usyms onto the ring buffer, etc., but it's mainly just a nice little clean up for consistency. Maybe it even eliminates some undiscovered lurking bugs.
bpftrace · Oct 4, 2024 · 5746676 · 5746676
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,9 @@ and this project adheres to
 
 ## Unreleased
 
+#### Breaking Changes
+- Return `uint32` instead of `uint64` for `pid` and `tid` builtins
+  - [#3441](https://github.com/bpftrace/bpftrace/pull/3441)
 #### Added
 - Add `--dry-run` CLI option
   - [#3203](https://github.com/bpftrace/bpftrace/pull/3203)

diff --git a/man/adoc/bpftrace.adoc b/man/adoc/bpftrace.adoc
@@ -1104,7 +1104,7 @@ For string arguments use the `str()` call to retrieve the value.
 | ID of the NUMA node executing the BPF program
 
 | pid
-| uint64
+| uint32
 | 4.2
 | get_current_pid_tgid
 | Process ID of the current thread (aka thread group ID), as seen from the init namespace
@@ -1134,7 +1134,7 @@ For string arguments use the `str()` call to retrieve the value.
 | Value returned by the function being traced (kretprobe, uretprobe, kretfunc)
 
 | tid
-| uint64
+| uint32
 | 4.2
 | get_current_pid_tgid
 | Thread ID of the current thread, as seen from the init namespace

diff --git a/src/ast/irbuilderbpf.cpp b/src/ast/irbuilderbpf.cpp
@@ -76,14 +76,14 @@ libbpf::bpf_func_id IRBuilderBPF::selectProbeReadHelper(AddrSpace as, bool str)
 Value *IRBuilderBPF::CreateGetPid(const location &loc)
 {
   Value *pidtgid = CreateGetPidTgid(loc);
-  Value *pid = CreateLShr(pidtgid, 32, "pid");
+  Value *pid = CreateTrunc(CreateLShr(pidtgid, 32), getInt32Ty(), "pid");
   return pid;
 }
 
 Value *IRBuilderBPF::CreateGetTid(const location &loc)
 {
   Value *pidtgid = CreateGetPidTgid(loc);
-  Value *tid = CreateAnd(pidtgid, 0xffffffff, "tid");
+  Value *tid = CreateTrunc(pidtgid, getInt32Ty(), "tid");
   return tid;
 }
 
@@ -93,15 +93,15 @@ AllocaInst *IRBuilderBPF::CreateUSym(llvm::Value *val,
 {
   std::vector<llvm::Type *> elements = {
     getInt64Ty(), // addr
-    getInt64Ty(), // pid
-    getInt64Ty(), // probe id
+    getInt32Ty(), // pid
+    getInt32Ty(), // probe id
   };
   StructType *usym_t = GetStructType("usym_t", elements, false);
   AllocaInst *buf = CreateAllocaBPF(usym_t, "usym");
 
   Value *pid = CreateGetPid(loc);
-  Value *probe_id_val = Constant::getIntegerValue(getInt64Ty(),
-                                                  APInt(64, probe_id));
+  Value *probe_id_val = Constant::getIntegerValue(getInt32Ty(),
+                                                  APInt(32, probe_id));
 
   // The extra 0 here ensures the type of addr_offset will be int64
   Value *addr_offset = CreateGEP(usym_t, buf, { getInt64(0), getInt32(0) });

diff --git a/src/ast/passes/semantic_analyser.cpp b/src/ast/passes/semantic_analyser.cpp
@@ -327,8 +327,9 @@ void SemanticAnalyser::visit(Builtin &builtin)
         LOG(ERROR, builtin.loc, err_) << "invalid program type";
         break;
     }
+  } else if (builtin.ident == "pid" || builtin.ident == "tid") {
+    builtin.type = CreateUInt32();
   } else if (builtin.ident == "nsecs" || builtin.ident == "elapsed" ||
-             builtin.ident == "pid" || builtin.ident == "tid" ||
              builtin.ident == "cgroup" || builtin.ident == "uid" ||
              builtin.ident == "gid" || builtin.ident == "cpu" ||
              builtin.ident == "rand" || builtin.ident == "numaid" ||

diff --git a/src/bpftrace.cpp b/src/bpftrace.cpp
@@ -570,8 +570,8 @@ std::vector<std::unique_ptr<IPrintable>> BPFtrace::get_arg_values(
       case Type::usym_t:
         arg_values.push_back(std::make_unique<PrintableString>(resolve_usym(
             *reinterpret_cast<uint64_t *>(arg_data + arg.offset),
-            *reinterpret_cast<uint64_t *>(arg_data + arg.offset + 8),
-            *reinterpret_cast<uint64_t *>(arg_data + arg.offset + 16))));
+            *reinterpret_cast<int32_t *>(arg_data + arg.offset + 8),
+            *reinterpret_cast<int32_t *>(arg_data + arg.offset + 12))));
         break;
       case Type::inet:
         arg_values.push_back(std::make_unique<PrintableString>(resolve_inet(
@@ -1545,8 +1545,8 @@ std::optional<std::vector<uint8_t>> BPFtrace::find_empty_key(
 
 std::string BPFtrace::get_stack(int64_t stackid,
                                 uint32_t nr_stack_frames,
-                                int pid,
-                                int probe_id,
+                                int32_t pid,
+                                int32_t probe_id,
                                 bool ustack,
                                 StackType stack_type,
                                 int indent)
@@ -1826,8 +1826,8 @@ std::string BPFtrace::resolve_inet(int af, const uint8_t *inet) const
 }
 
 std::string BPFtrace::resolve_usym(uint64_t addr,
-                                   int pid,
-                                   int probe_id,
+                                   int32_t pid,
+                                   int32_t probe_id,
                                    bool show_offset,
                                    bool show_module)
 {

diff --git a/src/bpftrace.h b/src/bpftrace.h
@@ -106,16 +106,16 @@ class BPFtrace {
   int print_map(const BpfMap &map, uint32_t top, uint32_t div);
   std::string get_stack(int64_t stackid,
                         uint32_t nr_stack_frames,
-                        int pid,
-                        int probe_id,
+                        int32_t pid,
+                        int32_t probe_id,
                         bool ustack,
                         StackType stack_type,
                         int indent = 0);
   std::string resolve_buf(const char *buf, size_t size);
   std::string resolve_ksym(uint64_t addr, bool show_offset = false);
   std::string resolve_usym(uint64_t addr,
-                           int pid,
-                           int probe_id,
+                           int32_t pid,
+                           int32_t probe_id,
                            bool show_offset = false,
                            bool show_module = false);
   std::string resolve_inet(int af, const uint8_t *inet) const;

diff --git a/src/output.cpp b/src/output.cpp
@@ -262,12 +262,12 @@ std::string Output::value_to_str(BPFtrace &bpftrace,
                                 8);
     }
     case Type::ksym_t: {
-      return bpftrace.resolve_ksym(read_data<uintptr_t>(value.data()));
+      return bpftrace.resolve_ksym(read_data<uint64_t>(value.data()));
     }
     case Type::usym_t: {
-      return bpftrace.resolve_usym(read_data<uintptr_t>(value.data()),
-                                   read_data<uintptr_t>(value.data() + 8),
-                                   read_data<uint64_t>(value.data() + 16));
+      return bpftrace.resolve_usym(read_data<uint64_t>(value.data()),
+                                   read_data<uint32_t>(value.data() + 8),
+                                   read_data<uint32_t>(value.data() + 12));
     }
     case Type::inet: {
       return bpftrace.resolve_inet(read_data<uint64_t>(value.data()),

diff --git a/src/types.cpp b/src/types.cpp
@@ -493,7 +493,7 @@ SizedType CreateHist()
 
 SizedType CreateUSym()
 {
-  return SizedType(Type::usym_t, 24);
+  return SizedType(Type::usym_t, 16);
 }
 
 SizedType CreateKSym()

diff --git a/tests/codegen/cast_int_to_arr.cpp.cpp b/tests/codegen/cast_int_to_arr.cpp.cpp
@@ -6,7 +6,7 @@ namespace codegen {
 
 TEST(codegen, cast_int_to_arr)
 {
-  test("kprobe:f { $a=(uint8[8])pid; @ = $a[0]; }", NAME);
+  test("kprobe:f { $a=(uint8[8])0; @ = $a[0]; }", NAME);
 }
 
 } // namespace codegen

diff --git a/tests/codegen/llvm/builtin_func_uprobe.ll b/tests/codegen/llvm/builtin_func_uprobe.ll
@@ -6,7 +6,7 @@ target triple = "bpf-pc-linux"
 %"struct map_t" = type { ptr, ptr, ptr, ptr }
 %"struct map_t.0" = type { ptr, ptr }
 %"struct map_t.1" = type { ptr, ptr, ptr, ptr }
-%usym_t = type { i64, i64, i64 }
+%usym_t = type { i64, i32, i32 }
 
 @LICENSE = global [4 x i8] c"GPL\00", section "license"
 @AT_x = dso_local global %"struct map_t" zeroinitializer, section ".maps", !dbg !0
@@ -24,13 +24,14 @@ entry:
   %func = load volatile i64, ptr %1, align 8
   call void @llvm.lifetime.start.p0(i64 -1, ptr %usym)
   %get_pid_tgid = call i64 inttoptr (i64 14 to ptr)()
-  %pid = lshr i64 %get_pid_tgid, 32
-  %2 = getelementptr %usym_t, ptr %usym, i64 0, i32 0
-  %3 = getelementptr %usym_t, ptr %usym, i64 0, i32 1
-  %4 = getelementptr %usym_t, ptr %usym, i64 0, i32 2
-  store i64 %func, ptr %2, align 8
-  store i64 %pid, ptr %3, align 8
-  store i64 0, ptr %4, align 8
+  %2 = lshr i64 %get_pid_tgid, 32
+  %pid = trunc i64 %2 to i32
+  %3 = getelementptr %usym_t, ptr %usym, i64 0, i32 0
+  %4 = getelementptr %usym_t, ptr %usym, i64 0, i32 1
+  %5 = getelementptr %usym_t, ptr %usym, i64 0, i32 2
+  store i64 %func, ptr %3, align 8
+  store i32 %pid, ptr %4, align 4
+  store i32 0, ptr %5, align 4
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@x_key")
   store i64 0, ptr %"@x_key", align 8
   %update_elem = call i64 inttoptr (i64 2 to ptr)(ptr @AT_x, ptr %"@x_key", ptr %usym, i64 0)
@@ -72,10 +73,10 @@ attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: re
 !18 = !DIBasicType(name: "int32", size: 32, encoding: DW_ATE_signed)
 !19 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !20, size: 64, offset: 192)
 !20 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !21, size: 64)
-!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 192, elements: !23)
+!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 128, elements: !23)
 !22 = !DIBasicType(name: "int8", size: 8, encoding: DW_ATE_signed)
 !23 = !{!24}
-!24 = !DISubrange(count: 24, lowerBound: 0)
+!24 = !DISubrange(count: 16, lowerBound: 0)
 !25 = !DIGlobalVariableExpression(var: !26, expr: !DIExpression())
 !26 = distinct !DIGlobalVariable(name: "ringbuf", linkageName: "global", scope: !2, file: !2, type: !27, isLocal: false, isDefinition: true)
 !27 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 128, elements: !28)

diff --git a/tests/codegen/llvm/builtin_func_uretprobe.ll b/tests/codegen/llvm/builtin_func_uretprobe.ll
@@ -6,7 +6,7 @@ target triple = "bpf-pc-linux"
 %"struct map_t" = type { ptr, ptr, ptr, ptr }
 %"struct map_t.0" = type { ptr, ptr }
 %"struct map_t.1" = type { ptr, ptr, ptr, ptr }
-%usym_t = type { i64, i64, i64 }
+%usym_t = type { i64, i32, i32 }
 
 @LICENSE = global [4 x i8] c"GPL\00", section "license"
 @AT_x = dso_local global %"struct map_t" zeroinitializer, section ".maps", !dbg !0
@@ -23,13 +23,14 @@ entry:
   %get_func_ip = call i64 inttoptr (i64 173 to ptr)(ptr %0)
   call void @llvm.lifetime.start.p0(i64 -1, ptr %usym)
   %get_pid_tgid = call i64 inttoptr (i64 14 to ptr)()
-  %pid = lshr i64 %get_pid_tgid, 32
-  %1 = getelementptr %usym_t, ptr %usym, i64 0, i32 0
-  %2 = getelementptr %usym_t, ptr %usym, i64 0, i32 1
-  %3 = getelementptr %usym_t, ptr %usym, i64 0, i32 2
-  store i64 %get_func_ip, ptr %1, align 8
-  store i64 %pid, ptr %2, align 8
-  store i64 0, ptr %3, align 8
+  %1 = lshr i64 %get_pid_tgid, 32
+  %pid = trunc i64 %1 to i32
+  %2 = getelementptr %usym_t, ptr %usym, i64 0, i32 0
+  %3 = getelementptr %usym_t, ptr %usym, i64 0, i32 1
+  %4 = getelementptr %usym_t, ptr %usym, i64 0, i32 2
+  store i64 %get_func_ip, ptr %2, align 8
+  store i32 %pid, ptr %3, align 4
+  store i32 0, ptr %4, align 4
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@x_key")
   store i64 0, ptr %"@x_key", align 8
   %update_elem = call i64 inttoptr (i64 2 to ptr)(ptr @AT_x, ptr %"@x_key", ptr %usym, i64 0)
@@ -71,10 +72,10 @@ attributes #1 = { nocallback nofree nosync nounwind willreturn memory(argmem: re
 !18 = !DIBasicType(name: "int32", size: 32, encoding: DW_ATE_signed)
 !19 = !DIDerivedType(tag: DW_TAG_member, name: "value", scope: !2, file: !2, baseType: !20, size: 64, offset: 192)
 !20 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !21, size: 64)
-!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 192, elements: !23)
+!21 = !DICompositeType(tag: DW_TAG_array_type, baseType: !22, size: 128, elements: !23)
 !22 = !DIBasicType(name: "int8", size: 8, encoding: DW_ATE_signed)
 !23 = !{!24}
-!24 = !DISubrange(count: 24, lowerBound: 0)
+!24 = !DISubrange(count: 16, lowerBound: 0)
 !25 = !DIGlobalVariableExpression(var: !26, expr: !DIExpression())
 !26 = distinct !DIGlobalVariable(name: "ringbuf", linkageName: "global", scope: !2, file: !2, type: !27, isLocal: false, isDefinition: true)
 !27 = !DICompositeType(tag: DW_TAG_structure_type, scope: !2, file: !2, size: 128, elements: !28)

diff --git a/tests/codegen/llvm/builtin_pid_tid.ll b/tests/codegen/llvm/builtin_pid_tid.ll
@@ -24,20 +24,23 @@ entry:
   %"@x_val" = alloca i64, align 8
   %"@x_key" = alloca i64, align 8
   %get_pid_tgid = call i64 inttoptr (i64 14 to ptr)()
-  %pid = lshr i64 %get_pid_tgid, 32
+  %1 = lshr i64 %get_pid_tgid, 32
+  %pid = trunc i64 %1 to i32
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@x_key")
   store i64 0, ptr %"@x_key", align 8
+  %2 = zext i32 %pid to i64
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@x_val")
-  store i64 %pid, ptr %"@x_val", align 8
+  store i64 %2, ptr %"@x_val", align 8
   %update_elem = call i64 inttoptr (i64 2 to ptr)(ptr @AT_x, ptr %"@x_key", ptr %"@x_val", i64 0)
   call void @llvm.lifetime.end.p0(i64 -1, ptr %"@x_val")
   call void @llvm.lifetime.end.p0(i64 -1, ptr %"@x_key")
   %get_pid_tgid1 = call i64 inttoptr (i64 14 to ptr)()
-  %tid = and i64 %get_pid_tgid1, 4294967295
+  %tid = trunc i64 %get_pid_tgid1 to i32
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@y_key")
   store i64 0, ptr %"@y_key", align 8
+  %3 = zext i32 %tid to i64
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@y_val")
-  store i64 %tid, ptr %"@y_val", align 8
+  store i64 %3, ptr %"@y_val", align 8
   %update_elem2 = call i64 inttoptr (i64 2 to ptr)(ptr @AT_y, ptr %"@y_key", ptr %"@y_val", i64 0)
   call void @llvm.lifetime.end.p0(i64 -1, ptr %"@y_val")
   call void @llvm.lifetime.end.p0(i64 -1, ptr %"@y_key")

diff --git a/tests/codegen/llvm/builtin_ustack.ll b/tests/codegen/llvm/builtin_ustack.ll
@@ -54,10 +54,11 @@ merge_block:                                      ; preds = %stack_scratch_failu
   store i32 %8, ptr %7, align 4
   %9 = getelementptr %stack_t, ptr %stack_args, i64 0, i32 2
   %get_pid_tgid = call i64 inttoptr (i64 14 to ptr)()
-  %pid = lshr i64 %get_pid_tgid, 32
-  store i64 %pid, ptr %9, align 8
-  %10 = getelementptr %stack_t, ptr %stack_args, i64 0, i32 3
-  store i32 0, ptr %10, align 4
+  %10 = lshr i64 %get_pid_tgid, 32
+  %pid = trunc i64 %10 to i32
+  store i32 %pid, ptr %9, align 4
+  %11 = getelementptr %stack_t, ptr %stack_args, i64 0, i32 3
+  store i32 0, ptr %11, align 4
   call void @llvm.lifetime.end.p0(i64 -1, ptr %stack_key)
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@x_key")
   store i64 0, ptr %"@x_key", align 8
@@ -71,17 +72,17 @@ lookup_stack_scratch_failure:                     ; preds = %entry
 lookup_stack_scratch_merge:                       ; preds = %entry
   %probe_read_kernel = call i64 inttoptr (i64 113 to ptr)(ptr %lookup_stack_scratch_map, i32 1016, ptr null)
   %get_stack = call i32 inttoptr (i64 67 to ptr)(ptr %0, ptr %lookup_stack_scratch_map, i32 1016, i64 256)
-  %11 = icmp sge i32 %get_stack, 0
-  br i1 %11, label %get_stack_success, label %get_stack_fail
+  %12 = icmp sge i32 %get_stack, 0
+  br i1 %12, label %get_stack_success, label %get_stack_fail
 
 get_stack_success:                                ; preds = %lookup_stack_scratch_merge
-  %12 = udiv i32 %get_stack, 8
-  %13 = getelementptr %stack_key, ptr %stack_key, i64 0, i32 1
-  store i32 %12, ptr %13, align 4
-  %14 = trunc i32 %12 to i8
-  %murmur_hash_2 = call i64 @murmur_hash_2(ptr %lookup_stack_scratch_map, i8 %14, i64 1)
-  %15 = getelementptr %stack_key, ptr %stack_key, i64 0, i32 0
-  store i64 %murmur_hash_2, ptr %15, align 8
+  %13 = udiv i32 %get_stack, 8
+  %14 = getelementptr %stack_key, ptr %stack_key, i64 0, i32 1
+  store i32 %13, ptr %14, align 4
+  %15 = trunc i32 %13 to i8
+  %murmur_hash_2 = call i64 @murmur_hash_2(ptr %lookup_stack_scratch_map, i8 %15, i64 1)
+  %16 = getelementptr %stack_key, ptr %stack_key, i64 0, i32 0
+  store i64 %murmur_hash_2, ptr %16, align 8
   %update_elem = call i64 inttoptr (i64 2 to ptr)(ptr @stack_bpftrace_127, ptr %stack_key, ptr %lookup_stack_scratch_map, i64 0)
   br label %merge_block
 

diff --git a/tests/codegen/llvm/call_avg.ll b/tests/codegen/llvm/call_avg.ll
@@ -25,29 +25,31 @@ entry:
   store i64 0, ptr %"@x_key", align 8
   %lookup_elem = call ptr inttoptr (i64 1 to ptr)(ptr @AT_x, ptr %"@x_key")
   %get_pid_tgid = call i64 inttoptr (i64 14 to ptr)()
-  %pid = lshr i64 %get_pid_tgid, 32
+  %1 = lshr i64 %get_pid_tgid, 32
+  %pid = trunc i64 %1 to i32
+  %2 = zext i32 %pid to i64
   %lookup_cond = icmp ne ptr %lookup_elem, null
   br i1 %lookup_cond, label %lookup_success, label %lookup_failure
 
 lookup_success:                                   ; preds = %entry
-  %1 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 0
-  %2 = load i64, ptr %1, align 8
-  %3 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 1
+  %3 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 0
   %4 = load i64, ptr %3, align 8
-  %5 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 0
-  %6 = add i64 %2, %pid
-  store i64 %6, ptr %5, align 8
-  %7 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 1
-  %8 = add i64 1, %4
+  %5 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 1
+  %6 = load i64, ptr %5, align 8
+  %7 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 0
+  %8 = add i64 %4, %2
   store i64 %8, ptr %7, align 8
+  %9 = getelementptr %avg_stas_val, ptr %lookup_elem, i64 0, i32 1
+  %10 = add i64 1, %6
+  store i64 %10, ptr %9, align 8
   br label %lookup_merge
 
 lookup_failure:                                   ; preds = %entry
   call void @llvm.lifetime.start.p0(i64 -1, ptr %avg_struct)
-  %9 = getelementptr %avg_stas_val, ptr %avg_struct, i64 0, i32 0
-  store i64 %pid, ptr %9, align 8
-  %10 = getelementptr %avg_stas_val, ptr %avg_struct, i64 0, i32 1
-  store i64 1, ptr %10, align 8
+  %11 = getelementptr %avg_stas_val, ptr %avg_struct, i64 0, i32 0
+  store i64 %2, ptr %11, align 8
+  %12 = getelementptr %avg_stas_val, ptr %avg_struct, i64 0, i32 1
+  store i64 1, ptr %12, align 8
   %update_elem = call i64 inttoptr (i64 2 to ptr)(ptr @AT_x, ptr %"@x_key", ptr %avg_struct, i64 0)
   call void @llvm.lifetime.end.p0(i64 -1, ptr %avg_struct)
   br label %lookup_merge

diff --git a/tests/codegen/llvm/call_hist.ll b/tests/codegen/llvm/call_hist.ll
@@ -21,8 +21,10 @@ entry:
   %lookup_elem_val = alloca i64, align 8
   %"@x_key" = alloca i64, align 8
   %get_pid_tgid = call i64 inttoptr (i64 14 to ptr)()
-  %pid = lshr i64 %get_pid_tgid, 32
-  %log2 = call i64 @log2(i64 %pid, i64 0)
+  %1 = lshr i64 %get_pid_tgid, 32
+  %pid = trunc i64 %1 to i32
+  %2 = zext i32 %pid to i64
+  %log2 = call i64 @log2(i64 %2, i64 0)
   call void @llvm.lifetime.start.p0(i64 -1, ptr %"@x_key")
   store i64 %log2, ptr %"@x_key", align 8
   %lookup_elem = call ptr inttoptr (i64 1 to ptr)(ptr @AT_x, ptr %"@x_key")
@@ -31,9 +33,9 @@ entry:
   br i1 %map_lookup_cond, label %lookup_success, label %lookup_failure
 
 lookup_success:                                   ; preds = %entry
-  %1 = load i64, ptr %lookup_elem, align 8
-  %2 = add i64 %1, 1
-  store i64 %2, ptr %lookup_elem, align 8
+  %3 = load i64, ptr %lookup_elem, align 8
+  %4 = add i64 %3, 1
+  store i64 %4, ptr %lookup_elem, align 8
   br label %lookup_merge
 
 lookup_failure:                                   ; preds = %entry