Comparison details:
The best compiler for the intel processors is surely icl, the compiler of Intel Corporation. It benefits of the inmense resources and know-how of Intel Corp.
GCC is a compiler that shares with lcc-win32 its low price, but has a long development history, and a team of many people dedicated to it.
lcc-win32 has been the result of the work of just three people. There is no budget, no institution whatsoever funding this work. In light of this conditions, the performances of lcc-win32 are quite acceptable, in my opinion.
Two different source sets were used for this comparison:
- The source code of egcs 1.1b itself. Around 12 Megabytes of C source, this code represents a real complex application.
- The symbolic calculator GP of Grenoble University in France. This code was used to measure the pure CPU integer speed in a real context of complex calculations. This program doesn't do any disk access other than reading a very small source file written in the calculator's internal language. The sources represent approx 1.5 megabytes of C code.
- The version of gcc used was GNU C++ version egcs-2.91.57
- The version of the icl compiler was version 2.4 P97176
- The version of lcc was 2.4, compiled Nov-3 98
- The machine used was a pentium MMX (intel) at 200MHZ with 64MB RAM.
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Compiling egcs 1.1b
- Icl compiler was given -Os (optimize for size), gcc was given -O, and lcc was given -O. If I changed the gcc optimizations for -O9, execution speed actually increased..., so I kept just plain -O, that seems to generate better code.
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-
| Compilation time with optimizations |
| icl |
650 sec |
| gcc |
472 sec |
| lcc |
213 sec |
-
-
| Compilation time with no optimizations |
| icl |
236 sec |
| gcc |
400 sec |
| lcc |
198.4 sec |
-
- To measure the speed of the resulting executable, the same source file was used: a large file of 270.999 bytes C source, that was given to the three generated compilers. The exact command line is:
-
- xxx.exe -O9 win32.c
-
- All executables were started twice, and only the second time was significant to avoid the influence of the disk cache.
-
-
| Execution time (optimized) |
| icl |
33.7 sec |
| gcc |
35.6 sec |
| lcc |
39.8 sec |
-
-
| Execution time (no optimizations) |
| icl |
43.5 sec |
| gcc |
46.6 sec |
| lcc |
47.8 sec |
-
-
| Code size (optimized) |
| icl |
2 056 192 |
| gcc |
1 728 000 |
| lcc |
1 831 968 |
-
-
| Code size (no optimizations) |
| icl |
2 946 048 |
| gcc |
2 679 808 |
| lcc |
2 213 920 |
-
-
Compiling the symbolic calculator 'gp'
- Icl compiler was given -Ox. gcc was given -O, and lcc was given -O.
-
-
| Compilation time with optimizations |
| icl |
192.3 sec |
| gcc |
175 sec |
| lcc |
43.5 sec |
-
-
| Compilation time with no optimizations |
| icl |
73 sec |
| gcc |
152.2 sec |
| lcc |
36.9 sec |
-
-
| Code size with optimizations |
| icl |
1 033 728 |
| gcc |
786 432 |
| lcc |
785 440 |
-
-
| Code size with no optimizations |
| icl |
1 218 560 |
| gcc |
1 248 256 |
| lcc |
969 248 |
-
-
| Execution time with optimizations |
| icl |
35 sec |
| gcc |
40.3 sec |
| lcc |
44 sec |
-
-
| Execution time with no optimizations |
| icl |
48.8 sec |
| gcc |
60.7 sec |
| lcc |
51.3 sec |
-
-
A floating point comparison
- As measure I used a matrix multiplication program. Since the source is very small (37K) there is no point in measuring the compilation speed. I used the option -0x for intel, -02 for gcc, and -O for lcc. The results are as follows:
-
-
| icl |
3.9 sec |
| gcc |
4.8 sec |
| lcc |
5.6 sec |
-
- It must be noted that Intel's compiler comes with a very high performance floating point math library. lcc (as gcc) uses the standard library of windows
- Another important point is that the results of icl and lcc were exactly identical. The results of gcc differed after the 13th digit.
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