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
3ac71b31f0
enable branch folding with an option
...
llvm-svn: 31335
2006-11-01 00:38:31 +00:00
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 $257, %ecx
jne LBB1_1 #label.0.no_exit.1_crit_edge.exitStub
jmp LBB1_2 #codeRepl5.exitStub
... which is much better layout :)
llvm-svn: 31282
2006-10-29 21:05:41 +00:00
c07657f59b
Teach branch folding to fold identical jump tables together and to delete
...
jump tables that are dead.
llvm-svn: 31273
2006-10-28 18:34:47 +00:00
af8383806b
improve deletion of blocks that just contain branches by knowing that
...
the pred block doesn't fall through into them if it's a jumptable.
llvm-svn: 31263
2006-10-28 17:32:47 +00:00
0d4479b77d
simplify code
...
llvm-svn: 31188
2006-10-25 22:21:37 +00:00
9feb308d51
turn off tail merging for now
...
llvm-svn: 31180
2006-10-25 18:08:50 +00:00
ceb51d8427
move single basic blocks that are neither fallen into nor fall out of into
...
a place more useful. In particular, if we can put them in a place where code
will be able to fall into it, do so. Otherwise, put it in a place it can fall
through into a successor. Otherwise, if preventing a fallthrough, move to the
end of the function, out of the way.
This deletes several hundred unconditional branches from spass.
llvm-svn: 31149
2006-10-24 01:12:32 +00:00
ebdb1d6724
Enable tail merging by default.
...
llvm-svn: 31140
2006-10-23 22:10:12 +00:00
5e1a34032b
More complete solution to deleting blocks and debug info.
...
llvm-svn: 31129
2006-10-23 14:56:37 +00:00
9f5a129543
don't break infinite loops
...
llvm-svn: 31102
2006-10-21 06:11:43 +00:00
28f17f45be
Use branch reversal to do stuff like this:
...
call L_strcmp$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)
llvm-svn: 31100
2006-10-21 05:54:00 +00:00
3ca52185af
Transform code like:
...
jle FOO
jmp BAR
BAR:
into:
jle FOO
BAR:
... whoa!
llvm-svn: 31098
2006-10-21 05:43:30 +00:00
4fe01c42ca
Three changes:
...
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.
llvm-svn: 31094
2006-10-21 05:08:28 +00:00
60c9d4dc76
Add an experimental cross-jumping implementation.
...
This is currently disabled by default and limited in several ways, but does
have a positive effect.
llvm-svn: 31090
2006-10-21 00:47:49 +00:00
73da320e50
Teach the branch folder to update debug info if it removes blocks with line
...
# notes in it.
llvm-svn: 31026
2006-10-17 23:17:27 +00:00
bca3e297fe
Enable deleting branches to successor blocks. With the previous patches,
...
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
llvm-svn: 31006
2006-10-17 18:16:40 +00:00
56c9d2597e
Reenable this pass, fixing the bugs in it.
...
It now correctly deletes unreachable blocks and blocks that are empty.
llvm-svn: 31000
2006-10-17 17:13:52 +00:00
47db29a405
disable this pass for now, it's causing issues
...
llvm-svn: 30951
2006-10-14 00:30:06 +00:00
3218e0eed5
falling off the end of a function is ok with an unreachable instruction.
...
llvm-svn: 30950
2006-10-14 00:21:48 +00:00
3e8e57c771
disable some objectionable code, maybe we can bring this pass to life
...
llvm-svn: 30939
2006-10-13 20:43:10 +00:00
835702a094
Remove trailing whitespace
...
llvm-svn: 21420
2005-04-21 22:36:52 +00:00
7c16caa336
Changes For Bug 352
...
Move include/Config and include/Support into include/llvm/Config,
include/llvm/ADT and include/llvm/Support. From here on out, all LLVM
public header files must be under include/llvm/.
llvm-svn: 16137
2004-09-01 22:55:40 +00:00
356f5a13f5
Dereferencing end() is bad.
...
llvm-svn: 15402
2004-08-01 09:51:42 +00:00
62c979ba07
Make OptimizeBlock take a MachineFunction::iterator instead of a
...
MachineBasicBlock* as a parameter so that nxext() and prior() helper
functions can work naturally on it.
llvm-svn: 15376
2004-07-31 19:24:41 +00:00
0f1c2ed907
Next on a pointer increments the pointer, not an iterator
...
llvm-svn: 15375
2004-07-31 18:40:36 +00:00
2303d3f660
Use next() helper to make code more readable. Use
...
MachineFunction::iterator instead of MachineBasicBlock* to avoid
dereferencing end iterators.
llvm-svn: 15373
2004-07-31 15:14:29 +00:00
1e8d8fd81f
Use MachineFunction::iterator instead of a MachineBasicBlock* because
...
FallThrough maybe == to MF.end().
llvm-svn: 15372
2004-07-31 15:03:52 +00:00
25e48dd2e0
Implement a simple target-independent CFG cleanup pass
...
llvm-svn: 15368
2004-07-31 10:01:27 +00:00
Chris Lattner