[clang] [clang][CodeGen] Zero init unspecified fields in initializers in C (PR #97121)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-armv7-lnt` running on `linaro-clang-armv7-lnt` while building `clang` at step 12 "test-suite".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/77/builds/3721

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 12 (test-suite) failure: test (failure)
...
cd /home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/SingleSource/UnitTests/Vector && /usr/local/bin/cmake -E create_symlink /home/tcwg-buildbot/worker/clang-armv7-lnt/test/test-suite/SingleSource/UnitTests/Vector/constpool.reference_output /home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/SingleSource/UnitTests/Vector/constpool.reference_output
gmake[2]: Leaving directory '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build'
[ 23%] Built target Vector-constpool
gmake[1]: Leaving directory '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build'
gmake: *** [Makefile:136: all] Error 2

2024-09-25 02:32:56 INFO: Testing...
2024-09-25 02:32:56 INFO: Execute: /home/tcwg-buildbot/worker/clang-armv7-lnt/stage1/bin/llvm-lit -v -j 32 /home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build -o /home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/outputtny53rq4.json
-- Testing: 3423 tests, 32 workers --
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_3.test (1 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_3.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s16_3' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_331.test (2 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_331.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s16_331' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_662.test (3 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_662.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s16_662' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_991.test (4 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s16_991.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s16_991' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_333.test (5 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_333.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s32_333' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_5.test (6 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_5.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s32_5' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_664.test (7 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_664.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s32_664' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_993.test (8 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s32_993.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s32_993' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s8_1.test (9 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s8_1.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s8_1' is missing
********************
NOEXE: test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s8_329.test (10 of 3423)
******************** TEST 'test-suite :: Bitcode/simd_ops/simd_ops_test_op_vaba_s8_329.test' FAILED ********************
Executable '/home/tcwg-buildbot/worker/clang-armv7-lnt/test/sandbox/build/Bitcode/simd_ops/simd_ops_test_op_vaba_s8_329' is missing
********************

```

</details>

https://github.com/llvm/llvm-project/pull/97121