[ci] Suppress the LLVM 22 Valgrind clang bitfield false positives.

The row's memcheck errors are all one Memcheck false positive: its cheap
unsigned-compare rule taints clang's `word >=u (1<<k)` lowering of a
bitfield test over a partially-defined word. All 2116 errors top out in
two clang functions -- FunctionProtoType's constructor and
CodeGenModule::SetLLVMFunctionAttributesForDefinition -- none in a clad
frame.

Replace --gen-suppressions=all with test/clad-valgrind-llvm22.supp,
scoped by top frame to those two functions so a genuine
uninitialised-value error anywhere else still fails the row. Five tests
still fail for real reasons that are not in a clang frame -- a
clad::array over-read, a delegating-constructor new/free mismatch, a
realloc use-after-free, and uninitialised locals in the f3 test source
-- so keep a tracked XFAIL: valgrind on each until the fixes land as
separate PRs.

clang false positive: llvm/llvm-project#194147

Valgrind Memcheck fix: https://bugs.kde.org/show_bug.cgi?id=523434

Author: vgvassilev

.github/workflows/ci.yml

@@ -101,12 +101,18 @@ jobs:
             extra_packages: 'libtrilinos-kokkos-dev ninja-build'
             extra_cmake_options: '-G Ninja'
 
-          - name: ubu24-clang19-runtime20-vg
+          - name: ubu24-clang20-runtime22-vg
             os: ubuntu-24.04
-            compiler: clang-19
+            compiler: clang-20
             extra_packages: 'valgrind'
             extra_cmake_options: '-DCLAD_TEST_USE_VG=On'
-            clang-runtime: '20'
+            clang-runtime: '22'
+            # Run Valgrind against the from-source llvm-release recipe
+            # (Release+Asserts), not apt: apt's -O2 binaries read uninitialised
+            # bitfield padding in ~399 clang/LLVM sites (llvm/llvm-project#194147)
+            # that no surgical suppression can cover. The recipe build tops out
+            # in two frames, handled by test/clad-valgrind-llvm22.supp.
+            use-recipe: 'true'
 
           - name: ubu24-arm-clang16-runtime17-shared-libs
             os: ubuntu-24.04-arm
@@ -192,7 +198,10 @@ jobs:
       with:
         version: ${{ matrix.clang-runtime }}
         os:      ${{ matrix.self-hosted-os || matrix.os }}
-        flavor:  ${{ matrix.flavor || 'system' }}
+        # use-recipe=true selects setup-llvm's empty flavor (the vanilla
+        # from-source llvm-release recipe); the `|| 'system'` default cannot
+        # emit that empty string on its own.
+        flavor:  ${{ matrix.use-recipe != 'true' && (matrix.flavor || 'system') || '' }}
 
     - name: Install extra Linux deps
       if: runner.os == 'Linux'

test/Analyses/ActivityReverse.cpp

@@ -2,8 +2,9 @@
 // RUN: ./Activity.out | %filecheck_exec %s
 // RUN: %cladclang -Xclang -plugin-arg-clad -Xclang -enable-va -Xclang -plugin-arg-clad -Xclang -disable-tbr %s -I%S/../../include -oActivity.out
 // RUN: ./Activity.out | %filecheck_exec %s
-//CHECK-NOT: {{.*error|warning|note:.*}}
+// FIXME: f3 reads uninitialised locals (test-source UB); drop when addressed.
 // XFAIL: valgrind
+//CHECK-NOT: {{.*error|warning|note:.*}}
 
 #include "clad/Differentiator/Differentiator.h"
 

test/Analyses/TBR.cpp

@@ -2,7 +2,6 @@
 // RUN: ./TBR.out | %filecheck_exec %s
 // RUN: %cladclang %s -I%S/../../include -oTBR.out
 // RUN: ./TBR.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 

test/Arrays/ArrayInputsReverseMode.C

@@ -2,7 +2,6 @@
 // RUN: ./ArrayInputsReverseMode.out | %filecheck_exec %s
 // RUN: %cladclang %s -I%S/../../include -Wno-unused-value -oArrayInputsReverseMode.out
 // RUN: ./ArrayInputsReverseMode.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 

test/CMakeLists.txt

@@ -90,7 +90,16 @@ option(CLAD_CUDA_TEST_USE_SANITIZER "Run Clang cuda tests with compute-sanitizer
 option(CLAD_TEST_USE_VG "Run Clang tests under Valgrind" OFF)
 set(CLAD_TEST_EXTRA_ARGS --verbose --show-skipped --show-unsupported)
 if(CLAD_TEST_USE_VG)
-  set(CLAD_TEST_EXTRA_ARGS ${CLAD_TEST_EXTRA_ARGS} "--vg --vg-arg=-q")
+  # Run under memcheck. The only errors an LLVM 22 x86_64 build produces on
+  # this suite are Memcheck's false "Conditional jump depends on uninitialised
+  # value" for clang's unsigned-compare lowering of a partially-defined
+  # bitfield word (llvm/llvm-project#194147); every one tops out in one of two
+  # clang functions, none in a clad frame. clad-valgrind-llvm22.supp silences
+  # exactly those two frames and nothing else, so a genuine uninitialised-value
+  # error anywhere still fails the row. Drop the file once the running Valgrind
+  # carries the CmpLTU/CmpLEU expensive-definedness fix.
+  set(CLAD_TEST_EXTRA_ARGS ${CLAD_TEST_EXTRA_ARGS}
+      "--vg --vg-arg=-q --vg-arg=--suppressions=${CMAKE_CURRENT_SOURCE_DIR}/clad-valgrind-llvm22.supp  --vg-arg=--expensive-definedness-checks=yes")
 endif ()
 if(CLAD_CUDA_TEST_USE_SANITIZER)
   set(CLAD_TEST_EXTRA_ARGS ${CLAD_TEST_EXTRA_ARGS} "--param" "cuda_sanitizer=1")

test/ErrorEstimation/Assignments.C

@@ -1,6 +1,5 @@
 // RUN: %cladclang -I%S/../../include -oAssignments.out %s 2>&1 | %filecheck %s
 // RUN: ./Assignments.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 #include "../TestUtils.h"

test/ErrorEstimation/BasicOps.C

@@ -1,6 +1,5 @@
 // RUN: %cladclang %s -I%S/../../include -Xclang -verify -oBasicOps.out 2>&1 | %filecheck %s
 // RUN: ./BasicOps.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 #include "../TestUtils.h"

test/ErrorEstimation/ConditonalStatements.C

@@ -1,6 +1,5 @@
 // RUN: %cladclang -I%S/../../include -oCondStmts.out %s 2>&1 | %filecheck %s
 // RUN: ./CondStmts.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 #include "../TestUtils.h"

test/ErrorEstimation/LoopsAndArrays.C

@@ -1,6 +1,5 @@
 // RUN: %cladclang -I%S/../../include -oLoopsAndArrays.out %s 2>&1 | %filecheck %s
 // RUN: ./LoopsAndArrays.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 #include "../TestUtils.h"

test/ErrorEstimation/LoopsAndArraysExec.C

@@ -1,6 +1,5 @@
 // RUN: %cladclang %s -I%S/../../include -oLoopsAndArraysExec.out 2>&1 | %filecheck %s
 // RUN: ./LoopsAndArraysExec.out | %filecheck_exec %s
-// XFAIL: valgrind
 
 #include "clad/Differentiator/Differentiator.h"
 #include "../TestUtils.h"