[all-commits] [llvm/llvm-project] ddb662: [WebAssembly][TTI] Avoid crash when costing scalab...

[Anutosh Bhat via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: ddb662d3cbadb7c2c96cc2c00f95a3a5562d5b06
      https://github.com/llvm/llvm-project/commit/ddb662d3cbadb7c2c96cc2c00f95a3a5562d5b06
  Author: Anutosh Bhat <andersonbhat491 at gmail.com>
  Date:   2026-07-30 (Thu, 30 Jul 2026)

  Changed paths:
    M llvm/lib/Target/WebAssembly/WebAssemblyTargetTransformInfo.cpp
    A llvm/test/Analysis/CostModel/WebAssembly/vector-shift.ll

  Log Message:
  -----------
  [WebAssembly][TTI] Avoid crash when costing scalable vector shifts (#212759)

I see the following 

```
 anutosh491 at Anutoshs-MacBook-Air llvm-project % cat /private/tmp/wasm-scalable-shift-cost.ll
define <vscale x 4 x i32> @shift(<vscale x 4 x i32> %x,
                                 <vscale x 4 x i32> %amount) {
  %result = shl <vscale x 4 x i32> %x, %amount
  ret <vscale x 4 x i32> %result
}


 anutosh491 at Anutoshs-MacBook-Air llvm-project % build-assert/bin/opt \
  -mtriple=wasm32-unknown-unknown \
  -mattr=+simd128 \
  -passes='print<cost-model>' \
  -disable-output \
  /private/tmp/wasm-scalable-shift-cost.ll
Printing analysis 'Cost Model Analysis' for function 'shift':
Cost Model: Assertion failed: (isa<To>(Val) && "cast<Ty>() argument of incompatible type!"), function cast, file Casting.h, line 572.
PLEASE submit a bug report to https://github.com/llvm/llvm-project/issues/ and include the crash backtrace and instructions to reproduce the bug.
Stack dump:
0.      Program arguments: build-assert/bin/opt -mtriple=wasm32-unknown-unknown -mattr=+simd128 -passes=print<cost-model> -disable-output /private/tmp/wasm-scalable-shift-cost.ll
1.      Running pass "function(print<cost-model>)" on module "/private/tmp/wasm-scalable-shift-cost.ll"
2.      Running pass "print<cost-model>" on function "shift"
 #0 0x0000000105b7a56c llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x102f6256c)
 #1 0x0000000105b78248 llvm::sys::RunSignalHandlers() (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x102f60248)
 #2 0x0000000105b7b170 SignalHandler(int, __siginfo*, void*) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x102f63170)
 #3 0x000000018b5f7744 (/usr/lib/system/libsystem_platform.dylib+0x1804fb744)
 #4 0x000000018b5ed8d8 (/usr/lib/system/libsystem_pthread.dylib+0x1804f18d8)
 #5 0x000000018b4f4644 (/usr/lib/system/libsystem_c.dylib+0x1803f8644)
 #6 0x000000018b4f38a0 (/usr/lib/system/libsystem_c.dylib+0x1803f78a0)
 #7 0x0000000104036ddc llvm::BasicTTIImplBase<llvm::WebAssemblyTTIImpl>::getArithmeticInstrCost(unsigned int, llvm::Type*, llvm::TargetTransformInfo::TargetCostKind, llvm::TargetTransformInfo::OperandValueInfo, llvm::TargetTransformInfo::OperandValueInfo, llvm::ArrayRef<llvm::Value const*>, llvm::Instruction const*) const (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x10141eddc)
 #8 0x000000010403b0ac llvm::TargetTransformInfoImplCRTPBase<llvm::WebAssemblyTTIImpl>::getInstructionCost(llvm::User const*, llvm::ArrayRef<llvm::Value const*>, llvm::TargetTransformInfo::TargetCostKind) const (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x1014230ac)
 #9 0x00000001049162c8 llvm::TargetTransformInfo::getInstructionCost(llvm::User const*, llvm::ArrayRef<llvm::Value const*>, llvm::TargetTransformInfo::TargetCostKind) const (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x101cfe2c8)
#10 0x00000001058d90b4 llvm::TargetTransformInfo::getInstructionCost(llvm::User const*, llvm::TargetTransformInfo::TargetCostKind) const (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x102cc10b4)
#11 0x000000010468a368 getCost(llvm::Instruction&, llvm::TargetTransformInfo::TargetCostKind, llvm::TargetTransformInfo&) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x101a72368)
#12 0x0000000104689dd4 llvm::CostModelPrinterPass::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x101a71dd4)
#13 0x0000000105186554 llvm::PassManager<llvm::Function, llvm::AnalysisManager<llvm::Function>>::run(llvm::Function&, llvm::AnalysisManager<llvm::Function>&) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x10256e554)
#14 0x000000010518a680 llvm::ModuleToFunctionPassAdaptor::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x102572680)
#15 0x0000000105185418 llvm::PassManager<llvm::Module, llvm::AnalysisManager<llvm::Module>>::run(llvm::Module&, llvm::AnalysisManager<llvm::Module>&) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x10256d418)
#16 0x0000000106127cb0 llvm::runPassPipeline(llvm::StringRef, llvm::Module&, llvm::TargetMachine*, llvm::TargetLibraryInfoImpl*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::ToolOutputFile*, llvm::StringRef, llvm::ArrayRef<llvm::PassPlugin>, llvm::ArrayRef<std::__1::function<void (llvm::PassBuilder&)>>, llvm::opt_tool::OutputKind, llvm::opt_tool::VerifierKind, bool, bool, bool, bool, bool, bool, bool, bool) (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x10350fcb0)
#17 0x0000000106131eac optMain (/Users/anutosh491/work/llvm-project/build-assert/bin/opt+0x103519eac)
#18 0x000000018b22fe00
zsh: abort      build-assert/bin/opt -mtriple=wasm32-unknown-unknown -mattr=+simd128 
```



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