Stream: git-wasmtime

Topic: wasmtime / PR #9215 Optimize 128-bit multiplication some...

Wasmtime GitHub notifications bot (Sep 08 2024 at 20:46):

alexcrichton opened PR #9215 from alexcrichton:more-mul-opts to bytecodealliance:main:

This commits adds support for more patterns of improved 128-bit
multiplication to the various backends of Cranelift. Notably:

• Using isplit to discard the lower bits of a multiplication maps
  directly to instructions on aarch64 and riscv64.

• Multiplying sign-extended 64-bit halves maps directly to supported
  instructions on s390x/riscv64/aarch64 (x86_64 already has these
  implemented).

This relies on adding a new method to test whether a Value is dead and
unused during lowering. While generally not useful this is applicable
for multi-result instructions such as isplit where one result may end
up not being used. This also is required because the egraph
optimizations can't currently handle multi-result instructions like
isplit so this can't be optimized to umulhi or smulhi in CLIF.

Wasmtime GitHub notifications bot (Sep 08 2024 at 20:46):

alexcrichton requested abrown for a review on PR #9215.

Wasmtime GitHub notifications bot (Sep 08 2024 at 20:46):

alexcrichton requested wasmtime-compiler-reviewers for a review on PR #9215.

Wasmtime GitHub notifications bot (Sep 11 2024 at 21:53):

abrown submitted PR review.

Wasmtime GitHub notifications bot (Sep 11 2024 at 22:08):

abrown merged PR #9215.

Last updated: Dec 13 2025 at 19:03 UTC