Improve build speeds?

I have implemented a language and I’m planning to release it soon. One of my goals is to have good build speeds so I can use it for web development. I noticed building ll files is faster than building C. However I noticed building a simple ll file can take 100+milliseconds on my desktop which isn’t terrible but isn’t extremely fast either (-fsyntax-only is about 50ms).

What can I do to build faster? I believe I saw some kind of C++ library. Is using that directly any faster? I’m not writing my compiler in C++ and I’m very likely to rewrite it in my language which will provide C linking. Am I out of luck?

The test C file I used was

int main() {
return 0;

I created the ll file by using clang hello.c -S -emit-llvm which generated the below. Usually I program on linux but there’s some debugging I’m doing on windows atm however last time I checked I believe the speed was comparable.

; ModuleID = ‘hello.c’
source_filename = “hello.c”
target datalayout = “e-m:w-i64:64-f80:128-n8:16:32:64-S128”
target triple = “x86_64-pc-windows-msvc19.10.25017”

$"??_C@_05COLMCDPH@Hello?$AA@" = comdat any

@"??_C@_05COLMCDPH@Hello?$AA@" = linkonce_odr dso_local unnamed_addr constant [6 x i8] c"Hello\00", comdat, align 1

; Function Attrs: noinline nounwind optnone uwtable
define dso_local i32 @main() #0 {
%1 = alloca i32, align 4
store i32 0, i32* %1, align 4
%2 = call i32 bitcast (i32 (…)* @puts to i32 (i8*))(i8 getelementptr inbounds ([6 x i8], [6 x i8]* @"??_C@_05COLMCDPH@Hello?$AA@", i32 0, i32 0))
ret i32 0

declare dso_local i32 @puts(…) #1

attributes #0 = { noinline nounwind optnone uwtable “correctly-rounded-divide-sqrt-fp-math”=“false” “disable-tail-calls”=“false” “less-precise-fpmad”=“false” “no-frame-pointer-elim”=“false” “no-infs-fp-math”=“false” “no-jump-tables”=“false” “no-nans-fp-math”=“false” “no-signed-zeros-fp-math”=“false” “no-trapping-math”=“false” “stack-protector-buffer-size”=“8” “target-cpu”=“x86-64” “target-features”="+fxsr,+mmx,+sse,+sse2,+x87" “unsafe-fp-math”=“false” “use-soft-float”=“false” }
attributes #1 = { “correctly-rounded-divide-sqrt-fp-math”=“false” “disable-tail-calls”=“false” “less-precise-fpmad”=“false” “no-frame-pointer-elim”=“false” “no-infs-fp-math”=“false” “no-nans-fp-math”=“false” “no-signed-zeros-fp-math”=“false” “no-trapping-math”=“false” “stack-protector-buffer-size”=“8” “target-cpu”=“x86-64” “target-features”="+fxsr,+mmx,+sse,+sse2,+x87" “unsafe-fp-math”=“false” “use-soft-float”=“false” }

!llvm.module.flags = !{!0, !1}
!llvm.ident = !{!2}

!0 = !{i32 1, !“wchar_size”, i32 2}
!1 = !{i32 7, !“PIC Level”, i32 2}
!2 = !{!“clang version 7.0.1 (tags/RELEASE_701/final)”}