[clang] [LifetimeSafety] Fix false positives for pointers in loops (PR #182368)

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github-actions[bot] wrote:

<!--PREMERGE ADVISOR COMMENT: Windows-->
# :window: Windows x64 Test Results

* 53233 tests passed
* 1024 tests skipped
* 1 test failed

## Failed Tests
(click on a test name to see its output)

### Clang
<details>
<summary>Clang.Sema/warn-lifetime-safety-dataflow.cpp</summary>

```
Exit Code: 1

Command Output (stdout):
--
# RUN: at line 1
c:\_work\llvm-project\llvm-project\build\bin\clang.exe -cc1 -internal-isystem C:\_work\llvm-project\llvm-project\build\lib\clang\23\include -nostdsysteminc -mllvm -debug-only=LifetimeFacts -Wlifetime-safety C:\_work\llvm-project\llvm-project\clang\test\Sema\warn-lifetime-safety-dataflow.cpp 2>&1 | c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe C:\_work\llvm-project\llvm-project\clang\test\Sema\warn-lifetime-safety-dataflow.cpp
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\clang.exe' -cc1 -internal-isystem 'C:\_work\llvm-project\llvm-project\build\lib\clang\23\include' -nostdsysteminc -mllvm -debug-only=LifetimeFacts -Wlifetime-safety 'C:\_work\llvm-project\llvm-project\clang\test\Sema\warn-lifetime-safety-dataflow.cpp'
# note: command had no output on stdout or stderr
# executed command: 'c:\_work\llvm-project\llvm-project\build\bin\filecheck.exe' 'C:\_work\llvm-project\llvm-project\clang\test\Sema\warn-lifetime-safety-dataflow.cpp'
# .---command stderr------------
# | C:\_work\llvm-project\llvm-project\clang\test\Sema\warn-lifetime-safety-dataflow.cpp:29:11: error: CHECK: expected string not found in input
# | // CHECK: Expire ({{[0-9]+}} (Path: p))
# |           ^
# | <stdin>:35:22: note: scanning from here
# |  Expire (0 (Path: x))
# |                      ^
# | <stdin>:36:2: note: possible intended match here
# |  Expire (1 (Path: p), Origin: 2 (Decl: p, Type : MyObj *))
# |  ^
# | 
# | Input file: <stdin>
# | Check file: C:\_work\llvm-project\llvm-project\clang\test\Sema\warn-lifetime-safety-dataflow.cpp
# | 
# | -dump-input=help explains the following input dump.
# | 
# | Input was:
# | <<<<<<
# |             .
# |             .
# |             .
# |            30:  Use (2 (Decl: p, Type : MyObj *), Read) 
# |            31:  Issue (1 (Path: p), ToOrigin: 3 (Expr: DeclRefExpr, Decl: p)) 
# |            32:  OriginFlow:  
# |            33:  Dest: 4 (Expr: ImplicitCastExpr, Type : MyObj *) 
# |            34:  Src: 2 (Decl: p, Type : MyObj *) 
# |            35:  Expire (0 (Path: x)) 
# | check:29'0                          X error: no match found
# |            36:  Expire (1 (Path: p), Origin: 2 (Decl: p, Type : MyObj *)) 
# | check:29'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# | check:29'1      ?                                                          possible intended match
# |            37:  OriginEscapes (4 (Expr: ImplicitCastExpr, Type : MyObj *), via Return) 
# | check:29'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |            38:  End of Block 
# | check:29'0     ~~~~~~~~~~~~~~
# |            39:  Block B0: 
# | check:29'0     ~~~~~~~~~~~
# |            40:  End of Block 
# | check:29'0     ~~~~~~~~~~~~~~
# |            41: ========================================== 
# | check:29'0     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# |             .
# |             .
# |             .
# | >>>>>>
# `-----------------------------
# error: command failed with exit status: 1

--

```
</details>

If these failures are unrelated to your changes (for example tests are broken or flaky at HEAD), please open an issue at https://github.com/llvm/llvm-project/issues and add the `infrastructure` label.

https://github.com/llvm/llvm-project/pull/182368