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path: root/lib/CodeGen/BranchFolding.cpp
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2007-05-31Arrange for only 1 of multiple branches to landing pad to be kept.Dale Johannesen
Do not remove empty landing pads (EH table needs to be updated) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37375 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-30Changed per review comment.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37355 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-29Make stable_sort in tail merging actually be stable (it never was, but didn'tDale Johannesen
matter until my last change). Reenable tail merging by default. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37354 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-24Blocks that cond-br and uncond-br/fallthrough to same block should haveDale Johannesen
only one successor. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37324 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-24Fix for PR1444: do not create two successors to the same block.Dale Johannesen
Temporarily, this breaks CodeGen/Generic/2006-02-12-InsertLibraryCall.ll by exposing an unrelated latent problem; working on that. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37323 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-23Two tail merging improvements:Dale Johannesen
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37315 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-22Make tail merging the default, except on powerPC. There was no prior artDale Johannesen
for a target-dependent default with a command-line override; this way should be generally usable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37285 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-18Remove some unneeded branches. (spotted by Evan, thanks)Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37198 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-15Remove extra CFG edges before doing these passes; it makes them happier.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@37089 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-10Do not generate branches to entry block. This fixes several test suiteDale Johannesen
failures on PPC (can happen only when prologue code is null) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36979 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-10Make tail merging handle many more cases (all it can, I think).Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36966 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-07Handle some non-exit blocks in tail merging.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36907 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-03Drop 'const'Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36662 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-02Use 'static const char' instead of 'static const int'.Devang Patel
Due to darwin gcc bug, one version of darwin linker coalesces static const int, which defauts PassID based pass identification. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36652 91177308-0d34-0410-b5e6-96231b3b80d8
2007-05-01Do not use typeinfo to identify pass in pass manager.Devang Patel
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36632 91177308-0d34-0410-b5e6-96231b3b80d8
2007-04-30Fix PR1228 and CodeGen/Generic/2007-04-30-LandingPadBranchFolding.llChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36602 91177308-0d34-0410-b5e6-96231b3b80d8
2007-03-20maintain LiveIn when splitting blocks (register scavenging needs it)Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35226 91177308-0d34-0410-b5e6-96231b3b80d8
2007-02-22Remove isAccessable.Jim Laskey
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34497 91177308-0d34-0410-b5e6-96231b3b80d8
2007-02-21Make branch folding behave in the presence of landing pads.Jim Laskey
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34476 91177308-0d34-0410-b5e6-96231b3b80d8
2007-02-17Fixes PR 1200Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34359 91177308-0d34-0410-b5e6-96231b3b80d8
2007-01-26Change the MachineDebugInfo to MachineModuleInfo to better reflect usageJim Laskey
for debugging and exception handling. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33550 91177308-0d34-0410-b5e6-96231b3b80d8
2007-01-26Make LABEL a builtin opcode.Jim Laskey
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33537 91177308-0d34-0410-b5e6-96231b3b80d8
2006-12-19Eliminate static ctors from StatisticsChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32698 91177308-0d34-0410-b5e6-96231b3b80d8
2006-12-06Detemplatize the Statistic class. The only type it is instantiated withChris Lattner
is 'unsigned'. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32279 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-18Don't transform in another bad case: if the block is empty, it should beChris Lattner
simplified before we do this xform so that our cost model is accurate. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31864 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-18Fix another case we *don't* want to do this xform.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31861 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-18make the previous change more aggressive, moving any block with no fallthrough.Chris Lattner
This speeds up yacr2 by 7% on a core2. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31856 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-18Minor code layout tweak: if we have something like this:Chris Lattner
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31855 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-08optimize single MBB loops better. In particular, produce:Chris Lattner
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31530 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-05Unbreak VC++ build.Jeff Cohen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31464 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-02For PR786:Reid Spencer
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31380 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-01give branch folding a simple heuristic to decide which block to split so thatChris Lattner
it inserts an uncond branch where it is less likely to cause a problem. This fixes some perf issues on ppc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31354 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-01make tail merging more aggressive. If two blocks share a common tail, but theChris Lattner
tail is not an entire block for either of them, pick one, split it, then merge the common part. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31336 91177308-0d34-0410-b5e6-96231b3b80d8
2006-11-01enable branch folding with an optionChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31335 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-29Make CanFallThrough more intelligent (so it can handle blocks with (e.g.) noChris Lattner
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 :) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31282 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-28Teach branch folding to fold identical jump tables together and to deleteChris Lattner
jump tables that are dead. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31273 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-28improve deletion of blocks that just contain branches by knowing thatChris Lattner
the pred block doesn't fall through into them if it's a jumptable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31263 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-25simplify codeChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31188 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-25turn off tail merging for nowChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31180 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-24move single basic blocks that are neither fallen into nor fall out of intoChris Lattner
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. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31149 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-23Enable tail merging by default.Chris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31140 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-23More complete solution to deleting blocks and debug info.Jim Laskey
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31129 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-21don't break infinite loopsChris Lattner
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31102 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-21Use branch reversal to do stuff like this:Chris Lattner
call L_strcmp$stub testl %eax, %eax - jne LBB26_208 #cond_true6020 - jmp LBB26_227 #bb7119 + je LBB26_227 #bb7119 LBB26_208: #cond_true6020 movl $l31_str14, 4(%esp) testl %eax, %eax - jne LBB26_704 #cond_true13042 - jmp LBB26_713 #bb13151 + je LBB26_713 #bb13151 LBB26_704: #cond_true13042 movl $_str52, 4(%esp) cmpl 76(%ecx), %eax - jge LBB26_1628 #cond_false63.i.i - jmp LBB26_1769 #_Z8makeGridP13mrSurfaceListidiidd.exit.i + jl LBB26_1769 #_Z8makeGridP13mrSurfaceListidiidd.exit.i LBB26_1628: #cond_false63.i.i movl $0, 48964(%esp) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31100 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-21Transform code like:Chris Lattner
jle FOO jmp BAR BAR: into: jle FOO BAR: ... whoa! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31098 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-21Three changes:Chris Lattner
1. Remove a bunch of ifdef'd code. 2. When a block just contains an uncond branch, change all blocks branching to it to jump to the destination instead. 3. If branch analysis tells us some edges in the machinecfg are not actually possible, remove them. #2 triggers a suprisingly large number of times. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31094 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-21Add an experimental cross-jumping implementation.Chris Lattner
This is currently disabled by default and limited in several ways, but does have a positive effect. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31090 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-17Teach the branch folder to update debug info if it removes blocks with lineChris Lattner
# notes in it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31026 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-17Enable deleting branches to successor blocks. With the previous patches,Chris Lattner
branch folding can now compile stuff like this: void foo(int W, int X, int Y, int Z) { if (W & 1) { for (; X;--X) bar(); } else if (W & 2) { for (; Y;--Y) bar(); } else if (W & 4) { for (; Z;--Z) bar(); } else if (W & 8) { for (; W;--W) bar(); } if (W) { bar(); } } contrived testcase where loops exits all end up merging together. To have the loop merges be: ... cmplw cr0, r30, r27 bne cr0, LBB1_14 ;bb38 LBB1_16: ;cond_next48.loopexit mr r27, r29 LBB1_20: ;cond_next48 cmplwi cr0, r27, 0 beq cr0, LBB1_22 ;UnifiedReturnBlock ... instead of: ... cmplw cr0, r30, r27 bne cr0, LBB1_14 ;bb38 LBB1_16: ;cond_next48.loopexit mr r27, r29 b LBB1_20 ;cond_next48 LBB1_17: ;cond_next48.loopexit1 b LBB1_20 ;cond_next48 LBB1_18: ;cond_next48.loopexit2 b LBB1_20 ;cond_next48 LBB1_19: ;cond_next48.loopexit3 LBB1_20: ;cond_next48 cmplwi cr0, r27, 0 beq cr0, LBB1_22 ;UnifiedReturnBlock ... This is CodeGen/PowerPC/branch-opt.ll git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31006 91177308-0d34-0410-b5e6-96231b3b80d8
2006-10-17Reenable this pass, fixing the bugs in it.Chris Lattner
It now correctly deletes unreachable blocks and blocks that are empty. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31000 91177308-0d34-0410-b5e6-96231b3b80d8
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