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Commit Graph

5 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
32cf19caa6 Fix register-dependent X86 tests.
llvm-svn: 128867
2011-04-05 00:32:44 +00:00
Dan Gohman
df2896d609 Eliminate more uses of llvm-as and llvm-dis.
llvm-svn: 81290
2009-09-08 23:54:48 +00:00
Evan Cheng
f18016728c On x86 favors folding short immediate into some arithmetic operations (e.g. add, and, xor, etc.) because materializing an immediate in a register is expensive in turns of code size.
e.g.
movl 4(%esp), %eax
addl $4, %eax

is 2 bytes shorter than

movl $4, %eax
addl 4(%esp), %eax

llvm-svn: 60139
2008-11-27 00:49:46 +00:00
Chris Lattner
d01522d33a Turn on my codegen prepare heuristic by default. It doesn't affect
performance in most cases on the Grawp tester, but does speed some 
things up (like shootout/hash by 15%).  This also doesn't impact 
compile time in a noticable way on the Grawp tester.

It also, of course, gets the testcase it was designed for right :)

llvm-svn: 60120
2008-11-26 22:16:44 +00:00
Chris Lattner
61c2a0fc8a This adds in some code (currently disabled unless you pass
-enable-smarter-addr-folding to llc) that gives CGP a better
cost model for when to sink computations into addressing modes.
The basic observation is that sinking increases register 
pressure when part of the addr computation has to be available
for other reasons, such as having a use that is a non-memory
operation.  In cases where it works, it can substantially reduce
register pressure.

This code is currently an overall win on 403.gcc and 255.vortex
(the two things I've been looking at), but there are several 
things I want to do before enabling it by default:

1. This isn't doing any caching of results, so it is much slower 
   than it could be.  It currently slows down release-asserts llc 
   by 1.7% on 176.gcc: 27.12s -> 27.60s.
2. This doesn't think about inline asm memory operands yet.
3. The cost model botches the case when the needed value is live
   across the computation for other reasons.

I'll continue poking at this, and eventually turn it on as llcbeta.

llvm-svn: 60074
2008-11-26 02:00:14 +00:00