b580d26e7d
Fix a problem that Nate noticed that boils down to an over conservative check
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in the code that does "select C, (X+Y), (X-Y) --> (X+(select C, Y, (-Y)))".
We now compile this loop:
LBB1_1: ; no_exit
add r6, r2, r3
subf r3, r2, r3
cmpwi cr0, r2, 0
addi r7, r5, 4
lwz r2, 0(r5)
addi r4, r4, 1
blt cr0, LBB1_4 ; no_exit
LBB1_3: ; no_exit
mr r3, r6
LBB1_4: ; no_exit
cmpwi cr0, r4, 16
mr r5, r7
bne cr0, LBB1_1 ; no_exit
into this instead:
LBB1_1: ; no_exit
srawi r6, r2, 31
add r2, r2, r6
xor r6, r2, r6
addi r7, r5, 4
lwz r2, 0(r5)
addi r4, r4, 1
add r3, r3, r6
cmpwi cr0, r4, 16
mr r5, r7
bne cr0, LBB1_1 ; no_exit
llvm-svn: 26356
2006-02-24 18:05:58 +00:00
e5521db5bc
Fix Regression/Transforms/LoopUnswitch/2006-02-22-UnswitchCrash.ll, which
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caused SPASS to fail building last night.
We can't trivially unswitch a loop if the exit block has phi nodes in it,
because we don't know which predecessor to use.
llvm-svn: 26320
2006-02-22 23:55:00 +00:00
8a5a324dac
Add some comments, simplify some code, and fix a bug that caused rewriting
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to rewrite with the wrong value.
llvm-svn: 26311
2006-02-22 06:37:14 +00:00
c2e3a7a4ce
improved support for branch folding, still not enabled.
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llvm-svn: 26289
2006-02-18 07:57:38 +00:00
0add83e969
Fix bugs identified by VC++.
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llvm-svn: 26287
2006-02-18 03:20:33 +00:00
19fa8ac938
Implement deletion of dead blocks, currently disabled.
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llvm-svn: 26285
2006-02-18 02:42:34 +00:00
cb853de534
a previous patch completely disabled trivial unswitching, this fixees it.
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Thanks to nate for pointing this out :)
llvm-svn: 26280
2006-02-18 01:32:04 +00:00
29f771ba21
initial trivial support for folding branches that have now-constant destinations.
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llvm-svn: 26279
2006-02-18 01:27:45 +00:00
8e44ff50b0
When unswitching a loop, make sure to update loop info with exit blocks in
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the right loop.
llvm-svn: 26277
2006-02-18 00:55:32 +00:00
d95665188b
Fix Transforms/SimplifyCFG/2006-02-17-InfiniteUnroll.ll
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llvm-svn: 26275
2006-02-18 00:33:17 +00:00
baddba41c7
Fix loops where the header has an exit, fixing a loop-unswitch crash on crafty
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llvm-svn: 26258
2006-02-17 06:39:56 +00:00
6fd136239b
start of some new simplification code, not thoroughly tested, use at your own
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risk :)
llvm-svn: 26248
2006-02-17 00:31:07 +00:00
8a77efe4f7
Rework the SelectionDAG-based implementations of SimplifyDemandedBits
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and ComputeMaskedBits to match the new improved versions in instcombine.
Tested against all of multisource/benchmarks on ppc.
llvm-svn: 26238
2006-02-16 21:11:51 +00:00
fa335f6083
Change SplitBlock to increment a BasicBlock::iterator, not an Instruction*. Apparently they do different things :)
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This fixes a testcase that nate reduced from spass.
Also included are a couple minor code changes that don't affect the generated
code at all.
llvm-svn: 26235
2006-02-16 19:36:22 +00:00
55f63f1b53
Fix VC++ warning.
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llvm-svn: 26228
2006-02-16 04:07:37 +00:00
ff42e81028
fix a bug where we unswitched the wrong way
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llvm-svn: 26225
2006-02-16 01:24:41 +00:00
fdff0bb43e
Implement trivial unswitching for switch stmts. This allows us to trivial
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unswitch this loop on 2 before sweating to unswitch on 1/3.
void test4(int N, int i, int C, int*P, int*Q) {
int j;
for (j = 0; j < N; ++j) {
switch (C) { // general unswitching.
default: P[i+j] = 0; break;
case 1: Q[i+j] = 0; break;
case 3: P[i+j] = Q[i+j]; break;
case 2: break; // TRIVIAL UNSWITCH on C==2
}
}
}
llvm-svn: 26223
2006-02-15 22:52:05 +00:00
e5cb76d744
make "trivial" unswitching significantly more general. It can now handle
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this for example:
for (j = 0; j < N; ++j) { // trivial unswitch
if (C)
P[i+j] = 0;
}
turning it into the obvious code without bothering to duplicate an empty loop.
llvm-svn: 26220
2006-02-15 22:03:36 +00:00
47da60130a
fix a bunch of alpha regressions. see bug 709
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llvm-svn: 26218
2006-02-15 21:13:37 +00:00
65152d80ec
Checking the wrong value. This caused us to emit silly code like
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Y = seteq bool X, true
instead of just using X :)
llvm-svn: 26215
2006-02-15 19:05:52 +00:00
01db04efb0
more refactoring, no functionality change.
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llvm-svn: 26194
2006-02-15 01:44:42 +00:00
b0cbe7106e
pull some code out into a function
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llvm-svn: 26191
2006-02-15 00:07:43 +00:00
9c5693fb2a
Canonicalize inner loops before outer loops. Inner loop canonicalization
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can provide work for the outer loop to canonicalize.
This fixes a case that breaks unswitching.
llvm-svn: 26189
2006-02-14 23:06:02 +00:00
cffbbee8d1
When splitting exit edges to canonicalize loops, make sure to put the new
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block in the appropriate loop nest.
Third time is the charm, right?
llvm-svn: 26187
2006-02-14 22:34:08 +00:00
0b8ec1a132
Use statistics to keep track of what flavors of loops we are unswitching
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llvm-svn: 26157
2006-02-14 01:01:41 +00:00
8b10ab3002
Implement Instcombine/and.ll:test34
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llvm-svn: 26155
2006-02-13 23:07:23 +00:00
7d8522884b
If any of the sign extended bits are demanded, the input sign bit is demanded
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for a sign extension.
This fixes InstCombine/2006-02-13-DemandedMiscompile.ll and Ptrdist/bc.
llvm-svn: 26152
2006-02-13 22:41:07 +00:00
68e7475777
Be careful not to request or look at bits shifted in from outside the size
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of the input. This fixes the mediabench/gsm/toast failure last night.
llvm-svn: 26138
2006-02-13 06:09:08 +00:00
f5b4ef7f58
remove some more dead special case code
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llvm-svn: 26135
2006-02-12 08:07:37 +00:00
5b2edb1fca
Eliminate special case hacks that are superceded by general purpose hacks
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llvm-svn: 26134
2006-02-12 08:02:11 +00:00
ee0f280743
Three changes:
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1. Teach GetConstantInType to handle boolean constants.
2. Teach instcombine to fold (compare X, CST) when X has known 0/1 bits.
Testcase here: set.ll:test22
3. Improve the "(X >> c1) & C2 == 0" folding code to allow a noop cast
between the shift and and. More aggressive bitfolding for other reasons
was turning signed shr's into unsigned shr's, leaving the noop cast in
the way.
llvm-svn: 26131
2006-02-12 02:07:56 +00:00
02f53ad3a2
Revert my last patch. It too breaks stuff
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llvm-svn: 26128
2006-02-12 01:59:10 +00:00
35248e06bc
Fix for my previously reverted patch
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llvm-svn: 26126
2006-02-11 21:24:54 +00:00
0157e7f55b
Port the recent innovations in ComputeMaskedBits to SimplifyDemandedBits.
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This allows us to simplify on conditions where bits are not known, but they
are not demanded either! This also fixes a couple of bugs in
ComputeMaskedBits that were exposed during this work.
In the future, swaths of instcombine should be removed, as this code
subsumes a bunch of ad-hockery.
llvm-svn: 26122
2006-02-11 09:31:47 +00:00
b24ce3a2a8
revert my previous change, it exposed other problems.
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llvm-svn: 26121
2006-02-11 08:47:47 +00:00
05bf90dddf
Make this check stricter. Disallow loop exit blocks from being shared by
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loops and their subloops.
llvm-svn: 26118
2006-02-11 02:13:17 +00:00
a6ae101afa
remove dead expr
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llvm-svn: 26116
2006-02-11 01:43:37 +00:00
fbadd7e1ee
implement unswitching of loops with switch stmts and selects in them
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llvm-svn: 26114
2006-02-11 00:43:37 +00:00
f1b151684d
Update PHI nodes in successors of exit blocks.
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llvm-svn: 26113
2006-02-10 23:26:14 +00:00
fe4151efe7
Reform the unswitching code in terms of edge splitting, not block splitting.
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llvm-svn: 26112
2006-02-10 23:16:39 +00:00
ec6b40a093
Fix a case where UnswitchTrivialCondition broke critical edges with
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phi's in the successors
llvm-svn: 26108
2006-02-10 19:08:15 +00:00
6e263155a6
add some notes, move some code around. Implement unswitching of loops
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with branches on partially invariant computations.
llvm-svn: 26104
2006-02-10 02:30:37 +00:00
4935417a84
Move code around to be more logical, no functionality change.
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llvm-svn: 26103
2006-02-10 02:01:22 +00:00
3fc3148b85
When unswitching a trivial loop, do admit we are doing it! :)
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llvm-svn: 26102
2006-02-10 01:36:35 +00:00
ed7a67b0de
Implement unconditional unswitching of 'trivial' loops, those loops that contain
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branches in their entry block that control whether or not the loop is a noop or not.
llvm-svn: 26101
2006-02-10 01:24:09 +00:00
4f0e66df6a
Simplify control flow a bit, note that unswitch preserves canonical loop form
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llvm-svn: 26098
2006-02-09 22:15:42 +00:00
8976219850
Make the threshold a parameter
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llvm-svn: 26093
2006-02-09 20:15:48 +00:00
2826e0511b
Simplify the loop-unswitch pass, by not even trying to unswitch loops with
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uses of loop values outside the loop. We need loop-closed SSA form to do
this right, or to use SSA rewriting if we really care.
llvm-svn: 26089
2006-02-09 19:14:52 +00:00
24cd2fa269
Fix 80-column violations
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llvm-svn: 26088
2006-02-09 07:41:14 +00:00
4534dd59a3
Enhance MVIZ in three ways:
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1. Teach it new tricks: in particular how to propagate through signed shr and sexts.
2. Teach it to return a bitset of known-1 and known-0 bits, instead of just zero.
3. Teach instcombine (AND X, C) to fold when we know all C bits of X.
This implements Regression/Transforms/InstCombine/bittest.ll, and allows
future things to be simplified.
llvm-svn: 26087
2006-02-09 07:38:58 +00:00
Chris Lattner