## Compiler {#compiler}

The build time overhead to building with [Profile Guided Optimization](/doc/pgo) has been reduced significantly.
Previously, large builds could see 100%+ build time increase from enabling PGO.
In Go 1.23, overhead should be in the single digit percentages.

## Assembler {#assembler}

pkg debug/pe, const IMAGE_FILE_DLL ideal-int
pkg debug/pe, const IMAGE_FILE_EXECUTABLE_IMAGE = 2
pkg debug/pe, const IMAGE_FILE_EXECUTABLE_IMAGE ideal-int
pkg debug/pe, const IMAGE_FILE_LARGE_ADDRESS_AWARE = 32
pkg debug/pe, const IMAGE_FILE_LARGE_ADDRESS_AWARE ideal-int
pkg debug/pe, const IMAGE_FILE_LINE_NUMS_STRIPPED = 4
pkg debug/pe, const IMAGE_FILE_LINE_NUMS_STRIPPED ideal-int
pkg debug/pe, const IMAGE_FILE_LOCAL_SYMS_STRIPPED = 8

pkg reflect, method (Value) Grow(int) #48000
pkg reflect, method (Value) SetZero() #52376
pkg regexp/syntax, const ErrLarge ErrorCode #56041
pkg regexp/syntax, const ErrLarge = "expression too large" #56041
pkg runtime/cgo (darwin-amd64-cgo), type Incomplete struct #46731
pkg runtime/cgo (darwin-arm64-cgo), type Incomplete struct #46731
pkg runtime/cgo (freebsd-386-cgo), type Incomplete struct #46731

# CL 134210043 archive/zip: add Writer.Flush, Brad Fitzpatrick <******@****.***>
pkg archive/zip, method (*Writer) Flush() error

# CL 97140043 compress/flate: add Reset() to allow reusing large buffers to compress multiple buffers, James Robinson <******@****.***>
pkg compress/flate, type Resetter interface { Reset }
pkg compress/flate, type Resetter interface, Reset(io.Reader, []uint8) error
pkg compress/zlib, type Resetter interface { Reset }