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.

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.

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.