Commit Graph

71 Commits

Author SHA1 Message Date
Duncan Sands d5ea194b6c If assertions are not enabled, we should return False here.
llvm-svn: 38535
2007-07-11 08:47:55 +00:00
David Greene d9034f717a Make this work with GLIBCXX_DEBUG.
llvm-svn: 38516
2007-07-10 22:00:30 +00:00
David Greene 451d1a6ecd Fix misue of iterator pointing to erased object. Uncovered by
_GLIBCXX_DEBUG.

llvm-svn: 37793
2007-06-29 02:45:24 +00:00
Evan Cheng 2afd702c20 Move CorrectExtraCFGEdges() from BranchFolding.cpp to a MachineBasicBlock method.
llvm-svn: 37633
2007-06-18 22:43:58 +00:00
Dale Johannesen 86798e5e11 Make throttle a hidden parameter, per review.
llvm-svn: 37511
2007-06-08 01:08:52 +00:00
Dale Johannesen 52fcf022f7 Throttle tail merging; handling blocks with large numbers of predecessors
is too slow.

llvm-svn: 37509
2007-06-08 00:34:27 +00:00
Dale Johannesen 0558dda319 Tail merging wasn't working for predecessors of landing pads. PR 1496.
llvm-svn: 37427
2007-06-04 23:52:54 +00:00
Evan Cheng df75785594 Move ReplaceUsesOfBlockWith() out of BranchFolding into a MachineBasicBlock general facility.
llvm-svn: 37408
2007-06-04 06:44:01 +00:00
Dale Johannesen 6e7cdce773 Fix CorrectExtraCFGEdges to allow for multiple LandingPad targets.
llvm-svn: 37394
2007-06-02 00:08:15 +00:00
Dale Johannesen 3c0a13762d Implement smarter algorithm for choosing which blocks to tail-merge.
See test/CodeGen/X86/test-pic-jtbl.ll for a case where it works well;
shaves another 10K off our favorite benchmark.  I was hesitant about
this because of compile speed, but seems to do OK on a bootstrap.

llvm-svn: 37392
2007-06-01 23:02:45 +00:00
Dale Johannesen 1a401e68a8 Arrange for only 1 of multiple branches to landing pad to be kept.
Do not remove empty landing pads (EH table needs to be updated)

llvm-svn: 37375
2007-05-31 21:54:00 +00:00
Dale Johannesen d14ad078c6 Changed per review comment.
llvm-svn: 37355
2007-05-30 00:32:01 +00:00
Dale Johannesen a69ebdbebc Make stable_sort in tail merging actually be stable (it never was, but didn't
matter until my last change).  Reenable tail merging by default.

llvm-svn: 37354
2007-05-29 23:47:50 +00:00
Dale Johannesen 1409b6a59b Blocks that cond-br and uncond-br/fallthrough to same block should have
only one successor.

llvm-svn: 37324
2007-05-24 18:31:55 +00:00
Dale Johannesen 1af8c870c7 Fix for PR1444: do not create two successors to the same block.
Temporarily, this breaks CodeGen/Generic/2006-02-12-InsertLibraryCall.ll
by exposing an unrelated latent problem; working on that.

llvm-svn: 37323
2007-05-24 17:39:32 +00:00
Dale Johannesen f4a77d2481 Two tail merging improvements:
When considering blocks with more than 2 predecessors, merge the block with
the largest number of matching insns, rather than the first block found.
Considering that 1 matching insn is enough to show a win for candidates that
already end with a branch.

llvm-svn: 37315
2007-05-23 21:07:20 +00:00
Dale Johannesen 82810c8a13 Make tail merging the default, except on powerPC. There was no prior art
for a target-dependent default with a command-line override; this way
should be generally usable.

llvm-svn: 37285
2007-05-22 17:14:46 +00:00
Dale Johannesen f8956178af Remove some unneeded branches. (spotted by Evan, thanks)
llvm-svn: 37198
2007-05-18 01:28:58 +00:00
Dale Johannesen 420a85d0cf Remove extra CFG edges before doing these passes; it makes them happier.
llvm-svn: 37089
2007-05-15 21:19:17 +00:00
Dale Johannesen cc8f571bc8 Do not generate branches to entry block. This fixes several test suite
failures on PPC (can happen only when prologue code is null)

llvm-svn: 36979
2007-05-10 23:59:23 +00:00
Dale Johannesen 6e16d09252 Make tail merging handle many more cases (all it can, I think).
llvm-svn: 36966
2007-05-10 01:01:49 +00:00
Dale Johannesen 9a25b3afcd Handle some non-exit blocks in tail merging.
llvm-svn: 36907
2007-05-07 20:57:21 +00:00
Devang Patel 8c78a0bff0 Drop 'const'
llvm-svn: 36662
2007-05-03 01:11:54 +00:00
Devang Patel e95c6ad802 Use 'static const char' instead of 'static const int'.
Due to darwin gcc bug, one version of darwin linker coalesces
static const int, which defauts PassID based pass identification.

llvm-svn: 36652
2007-05-02 21:39:20 +00:00
Devang Patel 09f162ca6a Do not use typeinfo to identify pass in pass manager.
llvm-svn: 36632
2007-05-01 21:15:47 +00:00
Chris Lattner 4dbbace4ff Fix PR1228 and CodeGen/Generic/2007-04-30-LandingPadBranchFolding.ll
llvm-svn: 36602
2007-04-30 23:35:00 +00:00
Dale Johannesen d05a1a2ade maintain LiveIn when splitting blocks (register scavenging needs it)
llvm-svn: 35226
2007-03-20 21:35:06 +00:00
Jim Laskey 9df1a1d8d8 Remove isAccessable.
llvm-svn: 34497
2007-02-22 16:39:03 +00:00
Jim Laskey 2dc5245c4a Make branch folding behave in the presence of landing pads.
llvm-svn: 34476
2007-02-21 22:42:20 +00:00
Dale Johannesen 12920dda9e Fixes PR 1200
llvm-svn: 34359
2007-02-17 00:44:34 +00:00
Jim Laskey c56315c2b5 Change the MachineDebugInfo to MachineModuleInfo to better reflect usage
for debugging and exception handling.

llvm-svn: 33550
2007-01-26 21:22:28 +00:00
Jim Laskey f9e5445ed4 Make LABEL a builtin opcode.
llvm-svn: 33537
2007-01-26 14:34:52 +00:00
Chris Lattner aee775a6b7 Eliminate static ctors from Statistics
llvm-svn: 32698
2006-12-19 22:41:21 +00:00
Chris Lattner 700b873130 Detemplatize the Statistic class. The only type it is instantiated with
is 'unsigned'.

llvm-svn: 32279
2006-12-06 17:46:33 +00:00
Chris Lattner ea017f66f7 Don't transform in another bad case: if the block is empty, it should be
simplified before we do this xform so that our cost model is accurate.

llvm-svn: 31864
2006-11-18 22:25:39 +00:00
Chris Lattner 56ec81ff73 Fix another case we *don't* want to do this xform.
llvm-svn: 31861
2006-11-18 21:56:39 +00:00
Chris Lattner 7acdc17fe4 make the previous change more aggressive, moving any block with no fallthrough.
This speeds up yacr2 by 7% on a core2.

llvm-svn: 31856
2006-11-18 21:30:35 +00:00
Chris Lattner 47ce26158f Minor code layout tweak: if we have something like this:
if (cond) goto BB2
BB1:
    ...
    return;
BB2:
   ...

Move BB1 to the end of the function so that the code falls through in the
non-return case.  This has the effect of moving assert (and other no-return
call) bodies and return blocks out of loops.

llvm-svn: 31855
2006-11-18 20:47:54 +00:00
Chris Lattner bf3b57f221 optimize single MBB loops better. In particular, produce:
LBB1_57:        #bb207.i
        movl 72(%esp), %ecx
        movb (%ecx,%eax), %cl
        movl 80(%esp), %edx
        movb %cl, 1(%edx,%eax)
        incl %eax
        cmpl $143, %eax
        jne LBB1_57     #bb207.i
        jmp LBB1_64     #cond_next255.i

intead of:

LBB1_57:        #bb207.i
        movl 72(%esp), %ecx
        movb (%ecx,%eax), %cl
        movl 80(%esp), %edx
        movb %cl, 1(%edx,%eax)
        incl %eax
        cmpl $143, %eax
        je LBB1_64      #cond_next255.i
        jmp LBB1_57     #bb207.i

This eliminates a branch per iteration of the loop.  This hurted PPC
particularly, because the extra branch meant another dispatch group for each
iteration of the loop.

llvm-svn: 31530
2006-11-08 01:03:21 +00:00
Jeff Cohen 7d6f3db3e2 Unbreak VC++ build.
llvm-svn: 31464
2006-11-05 19:31:28 +00:00
Reid Spencer de46e48420 For PR786:
Turn on -Wunused and -Wno-unused-parameter. Clean up most of the resulting
fall out by removing unused variables. Remaining warnings have to do with
unused functions (I didn't want to delete code without review) and unused
variables in generated code. Maintainers should clean up the remaining
issues when they see them. All changes pass DejaGnu tests and Olden.

llvm-svn: 31380
2006-11-02 20:25:50 +00:00
Chris Lattner 7cee6ddcd8 give branch folding a simple heuristic to decide which block to split so that
it inserts an uncond branch where it is less likely to cause a problem.  This
fixes some perf issues on ppc.

llvm-svn: 31354
2006-11-01 19:36:29 +00:00
Chris Lattner f505a5a063 make tail merging more aggressive. If two blocks share a common tail, but the
tail is not an entire block for either of them, pick one, split it, then
merge the common part.

llvm-svn: 31336
2006-11-01 01:16:12 +00:00
Chris Lattner 3ac71b31f0 enable branch folding with an option
llvm-svn: 31335
2006-11-01 00:38:31 +00:00
Chris Lattner 504eeda365 Make CanFallThrough more intelligent (so it can handle blocks with (e.g.) no
successors), and make island block movement more general.

This compiles CodeGen/X86/2006-04-27-ISelFoldingBug.ll to:

_loadAndRLEsource_no_exit_2E_1_label_2E_0:
        subl $8, %esp
        movl %esi, 4(%esp)
        movl %ebx, (%esp)
        movl 16(%esp), %eax
        movl 12(%esp), %ecx
LBB1_3: #label.0
        movl _last, %edx
        movl %edx, %esi
        incl %esi
        movl %esi, _last
        movl %ecx, %ebx
        # TRUNCATE movb %bl, %bl
        movl _block, %esi
        movb %bl, 1(%esi,%edx)
        cmpl %eax, _last
        jge LBB1_2      #codeRepl5.exitStub
LBB1_4: #label.0
        cmpl $257, %ecx
        je LBB1_2       #codeRepl5.exitStub
LBB1_1: #label.0.no_exit.1_crit_edge.exitStub
        movl $1, %eax
        movl (%esp), %ebx
        movl 4(%esp), %esi
        addl $8, %esp
        ret
LBB1_2: #codeRepl5.exitStub
        xorl %eax, %eax
        movl (%esp), %ebx
        movl 4(%esp), %esi
        addl $8, %esp
        ret

instead of:

_loadAndRLEsource_no_exit_2E_1_label_2E_0:
        subl $8, %esp
        movl %esi, 4(%esp)
        movl %ebx, (%esp)
        movl 16(%esp), %eax
        movl 12(%esp), %ecx
        jmp LBB1_3      #label.0
LBB1_1: #label.0.no_exit.1_crit_edge.exitStub
        movl $1, %eax
        movl (%esp), %ebx
        movl 4(%esp), %esi
        addl $8, %esp
        ret
LBB1_2: #codeRepl5.exitStub
        xorl %eax, %eax
        movl (%esp), %ebx
        movl 4(%esp), %esi
        addl $8, %esp
        ret
LBB1_3: #label.0
        movl _last, %edx
        movl %edx, %esi
        incl %esi
        movl %esi, _last
        movl %ecx, %ebx
        # TRUNCATE movb %bl, %bl
        movl _block, %esi
        movb %bl, 1(%esi,%edx)
        cmpl %eax, _last
        jge LBB1_2      #codeRepl5.exitStub
LBB1_4: #label.0
        cmpl $257, %ecx
        jne LBB1_1      #label.0.no_exit.1_crit_edge.exitStub
        jmp LBB1_2      #codeRepl5.exitStub

... which is much better layout :)

llvm-svn: 31282
2006-10-29 21:05:41 +00:00
Chris Lattner c07657f59b Teach branch folding to fold identical jump tables together and to delete
jump tables that are dead.

llvm-svn: 31273
2006-10-28 18:34:47 +00:00
Chris Lattner af8383806b improve deletion of blocks that just contain branches by knowing that
the pred block doesn't fall through into them if it's a jumptable.

llvm-svn: 31263
2006-10-28 17:32:47 +00:00
Chris Lattner 0d4479b77d simplify code
llvm-svn: 31188
2006-10-25 22:21:37 +00:00
Chris Lattner 9feb308d51 turn off tail merging for now
llvm-svn: 31180
2006-10-25 18:08:50 +00:00
Chris Lattner ceb51d8427 move single basic blocks that are neither fallen into nor fall out of into
a place more useful.  In particular, if we can put them in a place where code
will be able to fall into it, do so.  Otherwise, put it in a place it can fall
through into a successor.  Otherwise, if preventing a fallthrough, move to the
end of the function, out of the way.

This deletes several hundred unconditional branches from spass.

llvm-svn: 31149
2006-10-24 01:12:32 +00:00