wasmtime / PR #2195 machinst x64: two optimizations · git-wasmtime

Stream: git-wasmtime

Topic: wasmtime / PR #2195 machinst x64: two optimizations

Wasmtime GitHub notifications bot (Sep 11 2020 at 16:01):

bnjbvr edited PR #2195 from x64-refactor to main:

First optimization matches addresses of the form base+index+offset, where index is a constant, and tries to add the constant with offset. This has been proven useful for some temporary variables computations in Spidermonkey (e.g. address of global values).

Second optimization regenerates constants in new vregs in put_input_to_reg, minimizing their live ranges.

There are a few bonus pieces here and there:

fix a few places where regenerating constants would clobber the flags (b/o xor for 0 constants), by reordering calls to put_input_in_reg so they're before the comparison emission.

fix the generation of R64 constants

use a mov imm32 sign-extended to reg, whenever possible, when generating an i64 immediate.

See also commit details.

This is up to a 17% speedup in compile times of the embenchen micro benchmarks, and up to 10% reduction in runtime speed.

Wasmtime GitHub notifications bot (Sep 11 2020 at 16:13):

bnjbvr updated PR #2195 from x64-refactor to main:

First optimization matches addresses of the form base+index+offset, where index is a constant, and tries to add the constant with offset. This has been proven useful for some temporary variables computations in Spidermonkey (e.g. address of global values).

Second optimization regenerates constants in new vregs in put_input_to_reg, minimizing their live ranges.

There are a few bonus pieces here and there:

fix a few places where regenerating constants would clobber the flags (b/o xor for 0 constants), by reordering calls to put_input_in_reg so they're before the comparison emission.

fix the generation of R64 constants

use a mov imm32 sign-extended to reg, whenever possible, when generating an i64 immediate.

See also commit details.

This is up to a 17% speedup in compile times of the embenchen micro benchmarks, and up to 10% reduction in runtime speed.

Wasmtime GitHub notifications bot (Sep 11 2020 at 18:21):

cfallin submitted PR Review.

Wasmtime GitHub notifications bot (Sep 11 2020 at 18:21):

cfallin merged PR #2195.

Last updated: Dec 23 2024 at 12:05 UTC