Philip Reames e1ab08a5bd [RISCV] Functional llvm.vector.reduce.mul on scalable types (#193094) ...

RVV does not have an instruction for performing a horizontal multiply
reduction (either integer or floating point). However, a user of clang
can explicitly write at least the integer form via the
__builtin_reduce_mul construct, and currently we just crash when
compiling this.

This change converts the crash into functionally correct scalar loop to
process each element one by one at runtime. This will be slow, but at
least correct.

Note that to my knowledge we can't generate the floating point one
directly from C, but I decided to handle both for completeness while I
was here.

Written by Claude Code with guidance and review by me.

2026-04-22 07:34:33 -07:00

7.8 KiB

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