https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107241
Bug ID: 107241
Summary: std.bitmanip.bigEndianToNative et al not inlined
Product: gcc
Version: 12.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: d
Assignee: ibuclaw at gdcproject dot org
Reporter: witold.baryluk+gcc at gmail dot com
Target Milestone: ---
gdc fails to inline number of small functions that should fully inline and end
in single instruction.
on amd64 / x86, for example std.bitmanip.bigEndianToNative causes a chain of
calls / jumps, even with @attribute("flatten")
import std.bitmanip;
import gcc.attributes;
@attribute("flatten")
size_t f(char[] b) {
return std.bitmanip.bigEndianToNative!(size_t,
8)(cast(ubyte[8])(b[2..10]));
}
gcc -O3 -march=znver2 -frelease
pure nothrow @nogc @safe ulong
std.bitmanip.swapEndian!(ulong).swapEndian(const(ulong)):
mov rax, rdi
bswap rax
ret
pure nothrow @nogc @safe ulong std.bitmanip.endianToNativeImpl!(true, ulong,
8uL).endianToNativeImpl(ubyte[8]):
jmp pure nothrow @nogc @safe ulong
std.bitmanip.swapEndian!(ulong).swapEndian(const(ulong))
pure nothrow @nogc @safe ulong std.bitmanip.bigEndianToNative!(ulong,
8uL).bigEndianToNative(ubyte[8]):
jmp pure nothrow @nogc @safe ulong
std.bitmanip.endianToNativeImpl!(true, ulong, 8uL).endianToNativeImpl(ubyte[8])
ulong example.f(char[]):
mov rdi, QWORD PTR [rsi+2]
jmp pure nothrow @nogc @safe ulong
std.bitmanip.bigEndianToNative!(ulong, 8uL).bigEndianToNative(ubyte[8])
No issues with LDC.
ulong example.f(char[]):
mov rax, qword ptr [rsi + 2]
bswap rax
ret
godbolt: https://godbolt.org/z/Pj3f7oGso
