[clang] [llvm] [SystemZ] Add support for __builtin_setjmp and __builtin_longjmp (PR #116642)

[LLVM Continuous Integration via cfe-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-clang-x86_64-expensive-checks-debian` running on `gribozavr4` while building `clang,llvm` at step 6 "test-build-unified-tree-check-all".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/16/builds/10237

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

```
Step 6 (test-build-unified-tree-check-all) failure: test (failure)
******************** TEST 'LLVM :: CodeGen/SystemZ/builtin-setjmp-alloca.ll' FAILED ********************
Exit Code: 2

Command Output (stderr):
--
RUN: at line 10: /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/llc < /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/SystemZ/builtin-setjmp-alloca.ll -mtriple=s390x-linux-gnu -O2 | /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/SystemZ/builtin-setjmp-alloca.ll
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/llc -mtriple=s390x-linux-gnu -O2
+ /b/1/llvm-clang-x86_64-expensive-checks-debian/build/bin/FileCheck /b/1/llvm-clang-x86_64-expensive-checks-debian/llvm-project/llvm/test/CodeGen/SystemZ/builtin-setjmp-alloca.ll

# After Instruction Selection
# Machine code for function foo1: IsSSA, TracksLiveness
Frame Objects:
  fi#0: size=8, align=8, at location [SP]
  fi#1: size=4, align=8, at location [SP]

bb.0.entry:
  successors: %bb.1(0x40000000), %bb.3(0x40000000); %bb.1(50.00%), %bb.3(50.00%)

  %0:gr64bit = LA %stack.1, 0, $noreg
  STG killed %0:gr64bit, %stack.0.val, 0, $noreg :: (store (s64) into %ir.val)
  MVHI %stack.1, 0, 10 :: (volatile store (s32) into %ir.1, align 8)
  %1:addr64bit = LGRL target-flags(<unknown>) @buf :: (load (s64) from got)
  %7:gr64bit = LARL %bb.3
  STG %7:gr64bit, %1:addr64bit, 8, $noreg
  STG $r11d, %1:addr64bit, 0, $noreg
  STG $r15d, %1:addr64bit, 24, $noreg
  %8:gr32bit = LG $r15d, 0, $noreg
  STG %8:gr32bit, %1:addr64bit, 16, $noreg
  EH_SjLj_Setup %bb.3, <regmask>

bb.1.entry:
; predecessors: %bb.0
  successors: %bb.2(0x80000000); %bb.2(100.00%)

  %5:gr32bit = LHI 0

bb.2.entry:
; predecessors: %bb.1, %bb.3

  %2:gr32bit = PHI %5:gr32bit, %bb.1, %6:gr32bit, %bb.3
  %3:addr64bit = LG %stack.0.val, 0, $noreg :: (dereferenceable load (s64) from %ir.val)
  %4:gr64bit = LGF killed %3:addr64bit, 0, $noreg :: (volatile load (s32) from %ir.3)
  $r2d = COPY %4:gr64bit
  Return implicit $r2d

bb.3.entry (machine-block-address-taken):
; predecessors: %bb.0
  successors: %bb.2(0x80000000); %bb.2(100.00%)

  %6:gr32bit = LHI 1
...

```

</details>

https://github.com/llvm/llvm-project/pull/116642