[llvm] [StructurizeCFG] Hoist and simplify zero-cost incoming else phi values (PR #139605)

Thu Jul 10 10:13:16 PDT 2025

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-hip-vega20` running on `hip-vega20-0` while building `llvm` at step 3 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/123/builds/23108

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

```
Step 3 (annotate) failure: '../llvm-zorg/zorg/buildbot/builders/annotated/hip-build.sh --jobs=' (failure)
...
[22/59] Generating testplan.py
[23/59] Building C object tools/CMakeFiles/timeit-target.dir/timeit.c.o
[24/59] [TEST_SUITE_HOST_CC] Linking host executable timeit
[25/59] [TEST_SUITE_HOST_CC] Linking host executable fpcmp
[26/59] Building C object tools/CMakeFiles/fpcmp-target.dir/fpcmp.c.o
[27/59] Linking C executable tools/timeit-target
[28/59] Linking C executable tools/fpcmp-target
[29/59] Generating new.hip
[30/59] Generating algorithm.hip
[31/59] Building CXX object External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o
FAILED: External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o 
/home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin/clang++ -DNDEBUG  -O3 -DNDEBUG   -w -Werror=date-time --rocm-path=/opt/botworker/llvm/External/hip/rocm-6.3.0 --offload-arch=gfx908 --offload-arch=gfx90a --offload-arch=gfx1030 --offload-arch=gfx1100 -MD -MT External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o -MF External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o.d -o External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o -c /home/botworker/bbot/clang-hip-vega20/llvm-test-suite/External/HIP/memmove.hip
PHI nodes not grouped at top of basic block!
  %i.06.ph = phi i64 [ 0, %for.body.preheader ], [ %n.vec, %middle.block ]
label %for.body.preheader
in function _Z11init_kernelPhm
fatal error: error in backend: Broken function found, compilation aborted!
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 21.0.0git (https://github.com/llvm/llvm-project.git 8d3f497eb834a84b954241b8c4293f8387e75576)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin
Build config: +assertions
clang++: note: diagnostic msg: Error generating preprocessed source(s).
[32/59] Building CXX object External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o
FAILED: External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o 
/home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin/clang++ -DNDEBUG -DSTDLIB_VERSION=9999  -O3 -DNDEBUG   -w -Werror=date-time --rocm-path=/opt/botworker/llvm/External/hip/rocm-6.3.0 --offload-arch=gfx908 --offload-arch=gfx90a --offload-arch=gfx1030 --offload-arch=gfx1100 -MD -MT External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o -MF External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o.d -o External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o -c /home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/test-suite-build/External/HIP/new.hip
PHI nodes not grouped at top of basic block!
  %3103 = phi ptr addrspace(1) [ %3135, %3133 ], [ %3099, %3097 ]
label %3097
in function __ockl_dm_alloc
fatal error: error in backend: Broken function found, compilation aborted!
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 21.0.0git (https://github.com/llvm/llvm-project.git 8d3f497eb834a84b954241b8c4293f8387e75576)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin
Build config: +assertions
clang++: note: diagnostic msg: Error generating preprocessed source(s).
[33/59] Building CXX object External/HIP/CMakeFiles/empty-hip-6.3.0.dir/empty.hip.o
[34/59] Building CXX object External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o
FAILED: External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o 
/home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin/clang++ -DNDEBUG  -O3 -DNDEBUG   -w -Werror=date-time --rocm-path=/opt/botworker/llvm/External/hip/rocm-6.3.0 --offload-arch=gfx908 --offload-arch=gfx90a --offload-arch=gfx1030 --offload-arch=gfx1100 -xhip -mfma -MD -MT External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o -MF External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o.d -o External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o -c /home/botworker/bbot/clang-hip-vega20/llvm-test-suite/External/HIP/workload/ray-tracing/TheNextWeek/main.cc
PHI nodes not grouped at top of basic block!
  %3103 = phi ptr addrspace(1) [ %3135, %3133 ], [ %3099, %3097 ]
label %3097
in function __ockl_dm_alloc
fatal error: error in backend: Broken function found, compilation aborted!
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
Step 11 (Building HIP test-suite) failure: Building HIP test-suite (failure)
...
[22/59] Generating testplan.py
[23/59] Building C object tools/CMakeFiles/timeit-target.dir/timeit.c.o
[24/59] [TEST_SUITE_HOST_CC] Linking host executable timeit
[25/59] [TEST_SUITE_HOST_CC] Linking host executable fpcmp
[26/59] Building C object tools/CMakeFiles/fpcmp-target.dir/fpcmp.c.o
[27/59] Linking C executable tools/timeit-target
[28/59] Linking C executable tools/fpcmp-target
[29/59] Generating new.hip
[30/59] Generating algorithm.hip
[31/59] Building CXX object External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o
FAILED: External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o 
/home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin/clang++ -DNDEBUG  -O3 -DNDEBUG   -w -Werror=date-time --rocm-path=/opt/botworker/llvm/External/hip/rocm-6.3.0 --offload-arch=gfx908 --offload-arch=gfx90a --offload-arch=gfx1030 --offload-arch=gfx1100 -MD -MT External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o -MF External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o.d -o External/HIP/CMakeFiles/memmove-hip-6.3.0.dir/memmove.hip.o -c /home/botworker/bbot/clang-hip-vega20/llvm-test-suite/External/HIP/memmove.hip
PHI nodes not grouped at top of basic block!
  %i.06.ph = phi i64 [ 0, %for.body.preheader ], [ %n.vec, %middle.block ]
label %for.body.preheader
in function _Z11init_kernelPhm
fatal error: error in backend: Broken function found, compilation aborted!
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 21.0.0git (https://github.com/llvm/llvm-project.git 8d3f497eb834a84b954241b8c4293f8387e75576)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin
Build config: +assertions
clang++: note: diagnostic msg: Error generating preprocessed source(s).
[32/59] Building CXX object External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o
FAILED: External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o 
/home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin/clang++ -DNDEBUG -DSTDLIB_VERSION=9999  -O3 -DNDEBUG   -w -Werror=date-time --rocm-path=/opt/botworker/llvm/External/hip/rocm-6.3.0 --offload-arch=gfx908 --offload-arch=gfx90a --offload-arch=gfx1030 --offload-arch=gfx1100 -MD -MT External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o -MF External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o.d -o External/HIP/CMakeFiles/new-hip-6.3.0.dir/new.hip.o -c /home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/test-suite-build/External/HIP/new.hip
PHI nodes not grouped at top of basic block!
  %3103 = phi ptr addrspace(1) [ %3135, %3133 ], [ %3099, %3097 ]
label %3097
in function __ockl_dm_alloc
fatal error: error in backend: Broken function found, compilation aborted!
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)
clang version 21.0.0git (https://github.com/llvm/llvm-project.git 8d3f497eb834a84b954241b8c4293f8387e75576)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin
Build config: +assertions
clang++: note: diagnostic msg: Error generating preprocessed source(s).
[33/59] Building CXX object External/HIP/CMakeFiles/empty-hip-6.3.0.dir/empty.hip.o
[34/59] Building CXX object External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o
FAILED: External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o 
/home/botworker/bbot/clang-hip-vega20/botworker/clang-hip-vega20/llvm/bin/clang++ -DNDEBUG  -O3 -DNDEBUG   -w -Werror=date-time --rocm-path=/opt/botworker/llvm/External/hip/rocm-6.3.0 --offload-arch=gfx908 --offload-arch=gfx90a --offload-arch=gfx1030 --offload-arch=gfx1100 -xhip -mfma -MD -MT External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o -MF External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o.d -o External/HIP/CMakeFiles/TheNextWeek-hip-6.3.0.dir/workload/ray-tracing/TheNextWeek/main.cc.o -c /home/botworker/bbot/clang-hip-vega20/llvm-test-suite/External/HIP/workload/ray-tracing/TheNextWeek/main.cc
PHI nodes not grouped at top of basic block!
  %3103 = phi ptr addrspace(1) [ %3135, %3133 ], [ %3099, %3097 ]
label %3097
in function __ockl_dm_alloc
fatal error: error in backend: Broken function found, compilation aborted!
clang++: error: clang frontend command failed with exit code 70 (use -v to see invocation)

```

</details>

https://github.com/llvm/llvm-project/pull/139605