Commit Graph

20 Commits

Author SHA1 Message Date
Jim Grosbach
7707a0df5b Move the utility function UpdateTerminator() from CodePlacementOpt() into
MachineBasicBlock so other passes can utilize it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86947 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-12 03:55:33 +00:00
Dan Gohman
07adb85cb7 Re-apply r84295, with fixes to how the loop "top" and "bottom" blocks are
tracked. Instead of trying to manually keep track of these locations
while doing complex modifications, just recompute them when they're needed.
This fixes a bug in which the TopMBB and BotMBB were not correctly updated,
leading to invalid transformations.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84598 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-20 04:50:37 +00:00
Anton Korobeynikov
766fc1db16 Revert r84295, this unbreaks llvm-gcc bootstrap on x86-64/linux
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84516 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-19 18:21:09 +00:00
Daniel Dunbar
c499e32b37 Fix my -Asserts warning fix.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84372 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-17 23:15:04 +00:00
Daniel Dunbar
afc1587800 Suppress -Asserts warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84327 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-17 09:33:00 +00:00
Dan Gohman
3bdd8de280 Enhance CodePlacementOpt's unconditional intra-loop branch elimination logic
to be more general and understand more varieties of loops.

Teach CodePlacementOpt to reorganize the basic blocks of a loop so that
they are contiguous. This also includes a fair amount of logic for preserving
fall-through edges while doing so. This fixes a BranchFolding-ism where blocks
which can't be made to use a fall-through edge and don't conveniently fit
anywhere nearby get tossed out to the end of the function.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84295 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-17 00:32:43 +00:00
Dan Gohman
cd2ae14ce3 Make CodePlacementOpt align loops, rather than loop headers. The
header is just the entry block to the loop, and it needn't be at
the top of the loop in the code layout.

Remove the code that suppressed loop alignment for outer loops,
so that outer loops are aligned.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84158 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-15 00:36:22 +00:00
Dan Gohman
bd31b173d2 Fix this comment. The loop header is the loop entry point.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83437 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-07 00:33:10 +00:00
Bob Wilson
8ad05c4bdf Fix CodePlacementOpt::OptimizeIntraLoopEdges so that its return value
correctly indicates whether it changed the code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72038 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-18 21:02:18 +00:00
Evan Cheng
6ebf7bc740 Run code placement optimization for targets that want it (arm and x86 for now).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71726 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-13 21:42:09 +00:00
Evan Cheng
9d3094b38e If header of inner loop is aligned, do not align the outer loop header. We don't want to add nops in the outer loop for the sake of aligning the inner loop.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71609 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-12 23:58:14 +00:00
Bob Wilson
74b0ccc577 Fix pr4195: When iterating through predecessor blocks, break out of the loop
after finding the (unique) layout predecessor.  Sometimes a block may be listed
more than once, and processing it more than once in this loop can lead to
inconsistent values for FtTBB/FtFBB, since the AnalyzeBranch method does not
clear these values.  There's no point in continuing the loop regardless.
The testcase for this is reduced from the 2003-05-02-DependentPHI SingleSource
test.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71536 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-12 03:48:10 +00:00
Evan Cheng
5374405dc1 Oops. Don't forget to align single bb loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71363 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-09 19:18:01 +00:00
Evan Cheng
f045f80ba9 Enable loop bb placement optimization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71291 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-08 23:35:49 +00:00
Evan Cheng
0269d3cbf3 Don't align loop header unless the loop back edge is below the header.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71242 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-08 19:01:44 +00:00
Evan Cheng
4b7f7a6e1f Reverse branch condition only when there is a conditional branch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71214 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-08 09:35:53 +00:00
Nick Lewycky
0ab2dcee5b Add explicit braces to disambiguate nested if/else. Removes a warning.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71211 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-08 06:57:41 +00:00
Evan Cheng
45e0010e14 Optimize code placement in loop to eliminate unconditional branches or move unconditional branch to the outside of the loop. e.g.
///       A:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       <fallthrough to B>                                                                                                                                                 
///                                                                                                                                                                          
///       B:  --> loop header                                                                                                                                                
///       ...                                                                                                                                                                
///       jcc <cond> C, [exit]                                                                                                                                               
///                                                                                                                                                                          
///       C:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       jmp B                                                                                                                                                              
///                                                                                                                                                                          
/// ==>                                                                                                                                                                      
///                                                                                                                                                                          
///       A:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       jmp B                                                                                                                                                              
///                                                                                                                                                                          
///       C:  --> new loop header                                                                                                                                            
///       ...                                                                                                                                                                
///       <fallthough to B>                                                                                                                                                  
///                                                                                                                                                                          
///       B:                                                                                                                                                                 
///       ...                                                                                                                                                                
///       jcc <cond> C, [exit] 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71209 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-08 06:34:09 +00:00
Evan Cheng
7132e12ee5 Code refactoring.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71151 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-07 05:49:39 +00:00
Evan Cheng
bbf1db7213 Rename "loop aligner" pass to "code placement optimization" pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71150 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-07 05:42:24 +00:00