Commit Graph

10 Commits

Author SHA1 Message Date
Chris Lattner
82fec4e31d Fix a nasty bug that caused us to unroll EXTREMELY large loops due to overflow
in the size calculation.

This is not something you want to see:
Loop Unroll: F[main] Loop %no_exit Loop Size = 2 Trip Count = 2147483648 - UNROLLING!

The problem was that 2*2147483648 == 0.

Now we get:
Loop Unroll: F[main] Loop %no_exit Loop Size = 2 Trip Count = 2147483648 - TOO LARGE: 4294967296>100

Thanks to some anonymous person playing with the demo page that repeatedly
caused zion to go into swapping land.  That's one way to ensure you'll get
a quick bugfix.  :)

Testcase here: Transforms/LoopUnroll/2004-05-13-DontUnrollTooMuch.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13564 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-13 20:43:31 +00:00
Chris Lattner
c99acc3709 Fix PR325
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13081 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-20 20:26:03 +00:00
Chris Lattner
5864aebe92 Add #include
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13057 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-19 03:01:23 +00:00
Chris Lattner
f1ab4b4eac Change the ExitBlocks list from being explicitly contained in the Loop
structure to being dynamically computed on demand.  This makes updating
loop information MUCH easier.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13045 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 22:14:10 +00:00
Chris Lattner
e3a55865bb Reduce the unrolling limit
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13040 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 18:06:14 +00:00
Chris Lattner
cc43909bb6 If the preheader of the loop was the entry block of the function, make sure
that the exit block of the loop becomes the new entry block of the function.

This was causing a verifier assertion on 252.eon.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13039 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 17:38:42 +00:00
Chris Lattner
998f44f859 Be much more careful about how we update instructions outside of the loop
using instructions inside of the loop.  This should fix the MishaTest failure
from last night.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13038 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 17:32:39 +00:00
Chris Lattner
50ca0a195a After unrolling our single basic block loop, fold it into the preheader and exit
block.  The primary motivation for doing this is that we can now unroll nested loops.

This makes a pretty big difference in some cases.  For example, in 183.equake,
we are now beating the native compiler with the CBE, and we are a lot closer
with LLC.

I'm now going to play around a bit with the unroll factor and see what effect
it really has.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13034 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 06:27:43 +00:00
Chris Lattner
9c2cc4626b Fix a bug: this does not preserve the CFG!
While we're at it, add support for updating loop information correctly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13033 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 05:38:37 +00:00
Chris Lattner
83bf2880c3 Initial checkin of a simple loop unroller. This pass is extremely basic and
limited.  Even in it's extremely simple state (it can only *fully* unroll single
basic block loops that execute a constant number of times), it already helps improve
performance a LOT on some benchmarks, particularly with the native code generators.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13028 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-18 05:20:17 +00:00