https://bugs.llvm.org/show_bug.cgi?id=38430
Bug ID: 38430
Summary: Preprocessing is much slower than GCC on small files
Product: clang
Version: 6.0
Hardware: Other
OS: Linux
Status: NEW
Severity: enhancement
Priority: P
Component: Frontend
Assignee: unassignedclangb...@nondot.org
Reporter: husseyde...@gmail.com
CC: llvm-bugs@lists.llvm.org
Created attachment 20634
--> https://bugs.llvm.org/attachment.cgi?id=20634&action=edit
Makefile
Clang 6.0.1, installed from Termux repos.
GCC 8.2.0, installed from its-pointless.github.io
Termux, LG G3
System information:
Linux localhost 3.4.113-LineageXTD-R7 #1 SMP PREEMPT Fri Jun 15 20:42:06 CEST
2018 armv7l Android
Termux-packages arch:
arm
Android version:
8.1.0, LineageOS
Device manufacturer:
LGE
Device model:
LG-D851
Note that I have gotten similar results on Ubuntu WSL, but I need to do further
testing.
While preprocessing very large files has a similar result with clang sometimes
being faster, clang has terrible performance when invoked many times in a row
with small files:
For example, cd to your main include directory, and run these shell commands:
mkdir -p ~/cpptest
I=0
for file in *.h; do
echo "#include <$file>" > ~/cpptest/$I.h
I=$((I+1));
done
Now, put the attached Makefile in ~/cpptest and time make, first with
CPP="clang-6.0 -E", make clean, and next with CPP="gcc-8 -E". Remove any lines
or files that error and run again.
$ time make CPP="clang-6.0 -E"
real 1m14.787s
user 0m46.860s
sys 0m22.390s
$ make clean
$ time make CPP="gcc-8 -E"
real 0.19.910s
user 0m11.390s
sys 0m5.880s
$
--
You are receiving this mail because:
You are on the CC list for the bug._______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
