[llvm] [RISCV][TTI] Refactor getCastInstrCost to exit early (PR #86619)

[via llvm-commits]

zeroomega wrote:

Hi,

This patch is causing an assertion error when building builtins-riscv64-unknown-linux-gnu:

```
FAILED: CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o 
/b/s/w/ir/x/w/llvm_build/./bin/clang --target=riscv64-unknown-linux-gnu --sysroot=/b/s/w/ir/x/w/cipd/focal -DVISIBILITY_HIDDEN  --target=riscv64-unknown-linux-gnu -O2 -g -DNDEBUG -fno-lto -std=c11 -fPIC -fno-builtin -fvisibility=hidden -fomit-frame-pointer -DCOMPILER_RT_HAS_FLOAT16 -MD -MT CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o -MF CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o.d -o CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o -c /b/s/w/ir/x/w/llvm-llvm-project/compiler-rt/lib/builtins/comparedf2.c
clang: llvm/lib/Target/RISCV/RISCVSubtarget.h:184: unsigned int llvm::RISCVSubtarget::getELen() const: Assertion `hasVInstructions() && "Expected V extension"' failed.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace, preprocessed source, and associated run script.
Stack dump:
0.	Program arguments: /b/s/w/ir/x/w/llvm_build/./bin/clang --target=riscv64-unknown-linux-gnu --sysroot=/b/s/w/ir/x/w/cipd/focal -DVISIBILITY_HIDDEN --target=riscv64-unknown-linux-gnu -O2 -g -DNDEBUG -fno-lto -std=c11 -fPIC -fno-builtin -fvisibility=hidden -fomit-frame-pointer -DCOMPILER_RT_HAS_FLOAT16 -MD -MT CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o -MF CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o.d -o CMakeFiles/clang_rt.builtins-riscv64.dir/comparedf2.c.o -c /b/s/w/ir/x/w/llvm-llvm-project/compiler-rt/lib/builtins/comparedf2.c
1.	<eof> parser at end of file
2.	Optimizer
#0 0x0000558c74b4ae08 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/b/s/w/ir/x/w/llvm_build/./bin/clang+0x8948e08)
clang: error: clang frontend command failed with exit code 134 (use -v to see invocation)
Fuchsia clang version 19.0.0git (https://llvm.googlesource.com/llvm-project 817f453aa576286aaca0a6b0244e6ab08516b80c)
Target: riscv64-unknown-linux-gnu
Thread model: posix
InstalledDir: /b/s/w/ir/x/w/llvm_build/bin
clang: note: diagnostic msg: 
********************

PLEASE ATTACH THE FOLLOWING FILES TO THE BUG REPORT:
Preprocessed source(s) and associated run script(s) are located at:
clang: note: diagnostic msg: /b/s/w/ir/x/w/llvm_build/clang-crashreports/comparedf2-7e2acc.c
clang: note: diagnostic msg: /b/s/w/ir/x/w/llvm_build/clang-crashreports/comparedf2-7e2acc.sh
clang: note: diagnostic msg: 

********************
```

This issue still persist after your fix forward patch landed. Could you revert your changes and fix them and reland them?
Failed build: https://ci.chromium.org/ui/p/fuchsia/builders/toolchain.ci/clang-linux-x64/b8752425016802502289/overview

Entire stdout from the build: https://logs.chromium.org/logs/fuchsia/buildbucket/cr-buildbucket/8752425016802502289/+/u/clang/build/stdout

Thanks.

https://github.com/llvm/llvm-project/pull/86619