[llvm] 6d516c6 - [llvm][RISCV] Do not assume V extension on seeing vector type. (#166994)

[via llvm-commits]

Author: Chenguang Wang
Date: 2025-11-07T14:41:06-08:00
New Revision: 6d516c6e28a1fdac7229ab0a1ad47adc17ac0d92

URL: https://github.com/llvm/llvm-project/commit/6d516c6e28a1fdac7229ab0a1ad47adc17ac0d92
DIFF: https://github.com/llvm/llvm-project/commit/6d516c6e28a1fdac7229ab0a1ad47adc17ac0d92.diff

LOG: [llvm][RISCV] Do not assume V extension on seeing vector type. (#166994)

We have a private extension which also uses the vector type in the
frontend. Our platform does not have the V extension, so it triggered
assertion failures from within getLMULCost().

It feels reasonable to check for V extension before assuming LMUL
exists.

Added: 
    

Modified: 
    llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp

Removed: 
    


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diff  --git a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
index 7bc0b5b394828..332433b4e530b 100644
--- a/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
+++ b/llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
@@ -2140,7 +2140,8 @@ InstructionCost RISCVTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
   // Assume memory ops cost scale with the number of vector registers
   // possible accessed by the instruction.  Note that BasicTTI already
   // handles the LT.first term for us.
-  if (LT.second.isVector() && CostKind != TTI::TCK_CodeSize)
+  if (ST->hasVInstructions() && LT.second.isVector() &&
+      CostKind != TTI::TCK_CodeSize)
     BaseCost *= TLI->getLMULCost(LT.second);
   return Cost + BaseCost;
 }