CLANG-REPL(1)

🌸 NAME 🌸

clang-repl — bestie, this is the manual page for clang-repl 17 💖

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✨ DESCRIPTION ✨

okay so here's the whole vibe. you run it like this:

clang-repl [options] [code to run]

that's the usage, periodt. then there's a whole OPTIONS: section, and it's long — like, it ate and left no crumbs long. we got two little families in there: Color Options and General options. let's get into it 🫶

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👑 OPTIONS 👑

🎨 Color Options

• --color — use colors in your output, so it's giving cute terminal instead of sad monochrome (default=autodetect) 🌈

🛠️ General options

• --Xcc=<string> — an argument you wanna pass straight to the CompilerInvocation. yes, it goes to the compiler, no cap
• --aarch64-neon-syntax=<value> — pick what style of NEON code the AArch64 backend emits:
  • =generic — emit generic NEON assembly
  • =apple — emit Apple-style NEON assembly 🍎
• --aarch64-use-aa — turn on the use of AA during codegen.
• --abort-on-max-devirt-iterations-reached — abort when we hit the max iterations for the devirtualization CGSCC repeat pass. dramatic but fair 💀
• --allow-ginsert-as-artifact — let G_INSERT be considered an artifact. it's literally a hack around AMDGPU test infinite loops, so don't @ me
• --amdgpu-atomic-optimizer-strategy=<value> — choose DPP or Iterative strategy for scan:
  • =DPP — use DPP operations for scan
  • =Iterative — use the Iterative approach for scan
  • =None — disable the atomic optimizer
• --amdgpu-bypass-slow-div — skip the 64-bit divide for dynamic 32-bit values
• --amdgpu-disable-loop-alignment — don't align and prefetch loops, we're keeping it casual
• --amdgpu-dpp-combine — enable the DPP combiner
• --amdgpu-dump-hsa-metadata — dump AMDGPU HSA metadata
• --amdgpu-enable-merge-m0 — merge and hoist M0 initializations
• --amdgpu-enable-power-sched — enable scheduling to minimize mAI power bursts ⚡
• --amdgpu-promote-alloca-to-vector-limit=<uint> — maximum byte size to even consider promoting alloca to vector
• --amdgpu-sdwa-peephole — enable the SDWA peepholer
• --amdgpu-use-aa-in-codegen — enable the use of AA during codegen.
• --amdgpu-verify-hsa-metadata — verify AMDGPU HSA metadata
• --amdgpu-vgpr-index-mode — use GPR indexing mode instead of movrel for vector indexing
• --arm-add-build-attributes — (no description bestie, it's just there, mysterious main character energy 🙈)
• --arm-implicit-it=<value> — allow conditional instructions outdside of an IT block:
  • =always — accept in both ISAs, emit implicit ITs in Thumb
  • =never — warn in ARM, reject in Thumb
  • =arm — accept in ARM, reject in Thumb
  • =thumb — warn in ARM, emit implicit ITs in Thumb
• --asm-show-inst — emit internal instruction representation to the assembly file
• --atomic-counter-update-promoted — do counter update using atomic fetch add for promoted counters only
• --atomic-first-counter — use atomic fetch add for the first counter in a function (usually the entry counter)
• --bounds-checking-single-trap — use one trap block per function
• --bpf-stack-size=<int> — specify the BPF stack size limit
• --cfg-hide-cold-paths=<number> — hide blocks with relative frequency below the given value
• --cfg-hide-deoptimize-paths — (no description, it's just doing its thing ✨)
• --cfg-hide-unreachable-paths — (also no description, mysterious queen)
• --cost-kind=<value> — target cost kind:
  • =throughput — reciprocal throughput
  • =latency — instruction latency
  • =code-size — code size
  • =size-latency — code size and latency
• --cs-profile-generate — perform context sensitive PGO instrumentation
• --cs-profile-path=<string> — context sensitive profile file path
• --debug-info-correlate — use debug info to correlate profiles.
• --debugify-func-limit=<ulong> — set max number of processed functions per pass.
• --debugify-level=<value> — kind of debug info to add:
  • =locations — locations only
  • =location+variables — locations and variables
• --debugify-quiet — suppress verbose debugify output 🤫
• --disable-auto-upgrade-debug-info — disable autoupgrade of debug info
• --disable-i2p-p2i-opt — disables inttoptr/ptrtoint roundtrip optimization
• --disable-promote-alloca-to-lds — disable promote alloca to LDS
• --disable-promote-alloca-to-vector — disable promote alloca to vector
• --do-counter-promotion — do counter register promotion
• --dot-cfg-mssa=<file name for generated dot file> — file name for generated dot file
• --dwarf-version=<int> — Dwarf version
• --dwarf64 — generate debugging info in the 64-bit DWARF format
• --emit-compact-unwind-non-canonical — whether to try to emit Compact Unwind for non canonical entries.
• --emit-dwarf-unwind=<value> — whether to emit DWARF EH frame entries:
  • =always — always emit EH frame entries
  • =no-compact-unwind — only emit EH frame entries when compact unwind is not available
  • =default — use target platform default
• --emscripten-cxx-exceptions-allowed=<string> — the list of function names in which Emscripten-style exception handling is enabled (see the emscripten EMSCRIPTEN_CATCHING_ALLOWED options)
• --enable-cse-in-irtranslator — should enable CSE in irtranslator
• --enable-cse-in-legalizer — should enable CSE in Legalizer
• --enable-emscripten-cxx-exceptions — WebAssembly Emscripten-style exception handling
• --enable-emscripten-sjlj — WebAssembly Emscripten-style setjmp/longjmp handling
• --enable-gvn-hoist — enable the GVN hoisting pass (default = off)
• --enable-gvn-memdep — (no description, it's lowkey keeping secrets 💅)
• --enable-gvn-sink — enable the GVN sinking pass (default = off)
• --enable-load-in-loop-pre — (no description, iconic and unexplained)
• --enable-load-pre — (no description, still slaying)
• --enable-loop-simplifycfg-term-folding — (no description, we love a mystery 🦋)
• --enable-name-compression — enable name/filename string compression
• --enable-split-backedge-in-load-pre — (no description, it said nothing and left)
• --execute-concurrency=<uint> — the number of threads used to process all files in parallel. set it to 0 for hardware concurrency. heads up bestie, this flag only applies to all-TUs.
• --executor=<string> — the name of the executor to use.
• --experimental-debug-variable-locations — use experimental new value-tracking variable locations
• --fatal-warnings — treat warnings as errors. no more soft launches, it's all consequences now 😤
• --filter=<string> — only process files that match this filter. reminder: this flag only applies to all-TUs.
• --force-tail-folding-style=<value> — force the tail folding style:
  • =none — disable tail folding
  • =data — create lane mask for data only, using the active.lane.mask intrinsic
  • =data-without-lane-mask — create lane mask with compare/stepvector
  • =data-and-control — create lane mask using the active.lane.mask intrinsic, and use it for both data and control flow
  • =data-and-control-without-rt-check — similar to data-and-control, but remove the runtime check
• --fs-profile-debug-bw-threshold=<uint> — only show debug message if the source branch weight is greater than this value.
• --fs-profile-debug-prob-diff-threshold=<uint> — only show debug message if the branch probility is greater than this value (in percentage).
• --generate-merged-base-profiles — when generating nested context-sensitive profiles, always generate an extra base profile for a function with all its context profiles merged into it.
• --gpsize=<uint> — Global Pointer Addressing Size. the default size is 8.
• --hash-based-counter-split — rename the counter variable of a comdat function based on cfg hash
• --hexagon-rdf-limit=<uint> — (no description, it's giving enigma 🎀)
• --hot-cold-split — enable the hot-cold splitting pass
• --import-all-index — import all external functions in index.
• --incremental-linker-compatible — when used with filetype=obj, emit an object file which can be used with an incremental linker
• --instcombine-code-sinking — enable code sinking
• --instcombine-guard-widening-window=<uint> — how wide an instruction window to bypass looking for another guard
• --instcombine-max-num-phis=<uint> — maximum number phis to handle in intptr/ptrint folding
• --instcombine-max-sink-users=<uint> — maximum number of undroppable users for instruction sinking
• --instcombine-maxarray-size=<uint> — maximum array size considered when doing a combine
• --instcombine-negator-enabled — should we attempt to sink negations?
• --instcombine-negator-max-depth=<uint> — what is the maximal lookup depth when trying to check for viability of negation sinking.
• --instrprof-atomic-counter-update-all — make all profile counter updates atomic (for testing only) 🧪
• --internalize-public-api-file=<filename> — a file containing a list of symbol names to preserve
• --internalize-public-api-list=<list> — a list of symbol names to preserve
• --iterative-counter-promotion — allow counter promotion across the whole loop nest.

okay bestie that's part 1 of 3, don't go anywhere — more options are literally on the way 💖

• --lto-aix-system-assembler=<path> — the path to a system assembler. AIX only, bestie, it literally only picks this up on AIX.
• --lto-embed-bitcode=<value> — embed LLVM bitcode inside the object files that LTO produces. ✨
  • =none — do not embed. simple as that.
  • =optimized — embed after all the optimization passes have run.
  • =post-merge-pre-opt — embed post-merge, but before optimizations.
• --lto-pass-remarks-filter=<regex> — only record optimization remarks from passes whose names match the given regular expression. picky, and honestly? valid. 💅
• --lto-pass-remarks-format=<format> — the format used for serializing remarks (default: YAML).
• --lto-pass-remarks-output=<filename> — output filename for pass remarks.
• --matrix-default-layout=<value> — sets the default matrix layout.
  • =column-major — use column-major layout.
  • =row-major — use row-major layout.
• --matrix-print-after-transpose-opt — no description given, it's just out here vibing. 🦋
• --max-counter-promotions=<int> — max number of allowed counter promotions.
• --max-counter-promotions-per-loop=<uint> — max number of counter promotions per loop, so we don't crank the register pressure too much.
• --mc-relax-all — when used with filetype=obj, relax all fixups in the emitted object file.
• --mcabac — tbd. that's it. that's the description. iconic honestly. 💀
• --merror-missing-parenthesis — throw an error for missing parenthesis around predicate registers.
• --merror-noncontigious-register — throw an error for register names that aren't contigious. (yes, spelled exactly like that, we don't fix the spelling, that's the bit.)
• --mhvx — enable Hexagon Vector eXtensions. 🐝
• --mhvx=<value> — enable Hexagon Vector eXtensions, but tell it which one:
  • =v60 — build for HVX v60.
  • =v62 — build for HVX v62.
  • =v65 — build for HVX v65.
  • =v66 — build for HVX v66.
  • =v67 — build for HVX v67.
  • =v68 — build for HVX v68.
  • =v69 — build for HVX v69.
  • =v71 — build for HVX v71.
  • =v73 — build for HVX v73.
• --mips-compact-branches=<value> — MIPS specific: compact branch policy.
  • =never — do not use compact branches if possible.
  • =optimal — use compact branches where appropriate (default).
  • =always — always use compact branches if possible.
• --mips16-constant-islands — enable mips16 constant islands.
• --mips16-hard-float — enable mips16 hard float.
• --mir-strip-debugify-only — should mir-strip-debug only strip debug info from debugified modules by default.
• --misexpect-tolerance=<uint> — prevents emitting diagnostics when profile counts are within N% of the threshold.. (two dots, canonically, we respect it 💅)
• --mno-compound — disable looking for compound instructions for Hexagon.
• --mno-fixup — disable fixing up resolved relocations for Hexagon.
• --mno-ldc1-sdc1 — expand double precision loads and stores to their single precision counterparts.
• --mno-pairing — disable looking for duplex instructions for Hexagon.
• --mwarn-missing-parenthesis — warn for missing parenthesis around predicate registers.
• --mwarn-noncontigious-register — warn for register names that arent contigious.
• --mwarn-sign-mismatch — warn for mismatching a signed and unsigned value.
• --no-deprecated-warn — suppress all deprecated warnings.
• --no-discriminators — disable generation of discriminator information.
• --no-type-check — suppress type errors (Wasm).
• --no-warn — suppress all warnings. chaos mode, love that for you 🫶
• --nvptx-sched4reg — NVPTX specific: schedule for register pressue. (again, exact spelling, we keep it.)
• --pgo-block-coverage — use this option to enable basic block coverage instrumentation.
• --pgo-temporal-instrumentation — use this option to enable temporal instrumentation.
• --pgo-view-block-coverage-graph — create a dot file of CFGs with block coverage inference information. ✨ dot files, so aesthetic.
• --poison-checking-function-local — check that returns are non-poison (for testing).
• --print-pipeline-passes — print a -passes compatible string describing the pipeline (best-effort only).
• --r600-ir-structurize — use StructurizeCFG IR pass.
• --riscv-add-build-attributes — no description, just here. 🌸
• --runtime-counter-relocation — enable relocating counters at runtime.
• --safepoint-ir-verifier-print-only — no description given. 🎀
• --sample-profile-check-record-coverage=<N> — emit a warning if less than N% of records in the input profile are matched to the IR.
• --sample-profile-check-sample-coverage=<N> — emit a warning if less than N% of samples in the input profile are matched to the IR.
• --sample-profile-max-propagate-iterations=<uint> — maximum number of iterations to go through when propagating sample block/edge weights through the CFG.
• --sanitizer-early-opt-ep — insert sanitizers on OptimizerEarlyEP.
• --skip-ret-exit-block — suppress counter promotion if exit blocks contain ret.
• --speculative-counter-promotion-max-exiting=<uint> — the max number of exiting blocks of a loop to allow speculative counter promotion.
• --speculative-counter-promotion-to-loop — when the option is false, if the target block is in a loop, the promotion will be disallowed unless the promoted counter update can be further/iteratively promoted into an acyclic region.
• --summary-file=<string> — the summary file to use for function importing.
• --sve-tail-folding=<string> — control the use of vectorisation using tail-folding for SVE, where the option is specified in the form (Initial)[+(Flag1|Flag2|...)]:
  • disabled — (Initial) no loop types will vectorize using tail-folding.
  • default — (Initial) uses the default tail-folding settings for the target CPU.
  • all — (Initial) all legal loop types will vectorize using tail-folding.
  • simple — (Initial) use tail-folding for simple loops (not reductions or recurrences).
  • reductions — use tail-folding for loops containing reductions.
  • noreductions — inverse of above.
  • recurrences — use tail-folding for loops containing fixed order recurrences.
  • norecurrences — inverse of above.
  • reverse — use tail-folding for loops requiring reversed predicates.
  • noreverse — inverse of above.
• --tail-predication=<value> — MVE tail-predication pass options.
  • =disabled — don't tail-predicate loops.
  • =enabled-no-reductions — enable tail-predication, but not for reduction loops.
  • =enabled — enable tail-predication, including reduction loops.
  • =force-enabled-no-reductions — enable tail-predication, but not for reduction loops, and force this which might be unsafe. 😭
  • =force-enabled — enable tail-predication, including reduction loops, and force this which might be unsafe. 😭
• --thinlto-assume-merged — assume the input has already undergone ThinLTO function importing and the other pre-optimization pipeline changes.
• --threads=<int> — no description given. 🙈
• --type-based-intrinsic-cost — calculate intrinsics cost based only on argument types.
• --verify-region-info — verify region info (time consuming).
• --vp-counters-per-site=<number> — the average number of profile counters allocated per value profiling site.
• --vp-static-alloc — do static counter allocation for value profiler.
• --wasm-enable-eh — WebAssembly exception handling.
• --wasm-enable-sjlj — WebAssembly setjmp/longjmp handling.
• --x86-align-branch=<string> — specify types of branches to align (plus separated list of types):
  • jcc — indicates conditional jumps.
  • fused — indicates fused conditional jumps.
  • jmp — indicates direct unconditional jumps.
  • call — indicates direct and indirect calls.
  • ret — indicates rets.
  • indirect — indicates indirect unconditional jumps.
• --x86-align-branch-boundary=<uint> — control how the assembler should align branches with NOP. If the boundary's size is not 0, it should be a power of 2 and no less than 32. Branches will be aligned to prevent from being across or against the boundary of specified size. The default value 0 does not align branches.
• --x86-branches-within-32B-boundaries — align selected instructions to mitigate negative performance impact of Intel's micro code update for errata skx102.

⚠️ May break assumptions about labels corresponding to particular instructions, and should be used with caution. bestie, read that again. caution.

• --x86-pad-max-prefix-size=<uint> — maximum number of prefixes to use for padding.

---

🌟 Generic Options 🌟

• --help — display available options (--help-hidden for more).
• --help-list — display list of available options (--help-list-hidden for more).
• --version — display the version of this program.

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🦋 Polly Options 🦋

Configure the polly loop optimizer.

• --polly — enable the polly optimizer (with -O1, -O2 or -O3).
• --polly-2nd-level-tiling — enable a 2nd level loop of loop tiling.
• --polly-ast-print-accesses — print memory access functions.
• --polly-context=<isl parameter set> — extra constraints on the context parameters, bestie. Just drop them in 💅
• --polly-dce-precise-steps=<int> — the number of precise steps hanging out between two approximating iterations. And if you set it to -1? It schedules another approximation stage before the actual dead code elimination even happens. Iconic behavior fr.
• --polly-delicm-max-ops=<int> — max number of isl operations you're willing to invest in lifetime analysis. 0 means no limit at all, go feral 🫶
• --polly-detect-full-functions — lets the detection of full functions happen. periodt.
• --polly-dump-after — dumps the module after Polly transformations into a file suffixed with "-after".
• --polly-dump-after-file=<string> — dumps the module after Polly transformations to the file you literally name here.
• --polly-dump-before — dumps the module before Polly transformations into a file suffixed with "-before".
• --polly-dump-before-file=<string> — dumps the module before Polly transformations straight to the given file.
• --polly-enable-simplify — simplifies the SCoP after optimizations ✨
• --polly-ignore-func=<string> — ignores functions matching a regex. Multiple regexes? Comma separate them, queen. Scop detection will ignore every function that matches ANY of the regexes you handed over.
• --polly-isl-arg=<argument> — an option passed to ISL. that's it, that's the tweet.
• --polly-matmul-opt — performs optimizations of matrix multiplications based on pattern matching 🧚
• --polly-on-isl-error-abort — aborts if an isl error is encountered. no chill, no mercy 💀
• --polly-only-func=<string> — only runs on functions matching a regex. Multiple regexes get comma separated, and scop detection will run on all functions that match ANY of the regexes provided.
• --polly-only-region=<identifier> — only runs on certain regions (the provided identifier must appear in the name of the region's entry block
• --polly-only-scop-detection — runs scop detection only, no other optimizations. just a lil peek 👀
• --polly-optimized-scops — Polly dumps the polyhedral description of Scops optimized with the isl scheduling optimizer, and the set of post-scheduling transformations is applied on the schedule tree.
• --polly-parallel — generates thread parallel code (isl codegen only).
• --polly-parallel-force — forces generation of thread parallel code, ignoring any cost model. main character energy, honestly.
• --polly-pattern-matching-based-opts — performs optimizations based on pattern matching 🔥
• --polly-postopts — applies post-rescheduling optimizations such as tiling (requires -polly-reschedule).
• --polly-pragma-based-opts — applies user-directed transformation from metadata.
• --polly-pragma-ignore-depcheck — skips the dependency check for pragma-based transformations. living dangerously, i respect it 🙈
• --polly-process-unprofitable — processes scops that are unlikely to benefit from Polly optimizations.
• --polly-register-tiling — enables register tiling ⭐
• --polly-report — prints information about the activities of Polly.
• --polly-reschedule — optimizes SCoPs using ISL.
• --polly-show — highlights the code regions that will be optimized in a (CFG BBs and LLVM-IR instructions).
• --polly-show-only — highlights the code regions that will be optimized in a (CFG only BBs).
• --polly-stmt-granularity=<value> — the algorithm used for splitting basic blocks into multiple statements:
  • =bb — one statement per basic block
  • =scalar-indep — scalar independence heuristic
  • =store — store-level granularity
• --polly-tc-opt — performs optimizations of tensor contractions based on pattern matching 💜
• --polly-tiling — enables loop tiling 🌸
• --polly-vectorizer=<value> — selects the vectorization strategy:
  • =none — no Vectorization
  • =stripmine — strip-mine outer loops for the loop-vectorizer to trigger

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okay bestie that's the whole page, every last Polly flag accounted for, no cap 🎀 that was <rainbow>clang-repl 17</rainbow>, dated June 2025 — go forth and optimize, you absolute icon 👑💖