Good News. Intel's ICC 8.0 Beta looks promising, now.
From:
Paul A. Renard
Subject:
Good News. Intel's ICC 8.0 Beta looks promising, now.
Date:
Tue, 03 Jun 2003 12:11:06 -0700
Back in February, 2003, I reported that Intel's icc 7.0
compiler was producing code using Pooma constructs that was 2X-4X slower
than KCC. Since then, the folks at Intel have worked hard, and for
my little test (reproduced at the end of this message), the icc 8.0 Beta
compiler (l_cc_b_8.0.023) is now producing code slightly faster
(maybe 5-10%) than KCC, and certainly comparable to hand-written
loops.
The only optimization items for compiling were:
-O3
-DNOPAssert -DNOCTAssert -tpp7 -xW
but the last two are particular to Pentium 4 vectorization, which plays a
very small part in the tests I did, and which probably caused the
"slightly faster", rather than "just about the same
speed".
So, icc 8.0 seems to be a useful choice in compilers (for Linux and
Windows).
// Then the following is called:
void compute(){
u *= cx(I)*cy(J); // runs 4X slower with icc
than KCC
}
When I time this routine, I find that it runs about 4X
slower when compiled with Intel's icc (Version 7, -O3 -DNOPAssert
-DNOCTASSERT) than with KCC (version 4.0f, +K3 -DNOPAssert,
-DNOCTAssert). As expected, the KCC version runs as fast as
hand-written loops.