Chris Lattner
5bad19bde7
Instcombine X/-1 --> 0-X
...
llvm-svn: 13172
2004-04-26 14:01:59 +00:00
Chris Lattner
b72fa5f541
Move the scev expansion code into this pass, where it belongs. There is
...
still room for cleanup, but at least the code modification is out of the
analysis now.
llvm-svn: 13135
2004-04-23 21:29:48 +00:00
Chris Lattner
6716bcd0cc
Disable a previous patch that was causing indvars to loop infinitely :(
...
llvm-svn: 13108
2004-04-22 15:12:36 +00:00
Chris Lattner
507ba1c3c3
Fix an extremely serious thinko I made in revision 1.60 of this file.
...
llvm-svn: 13106
2004-04-22 14:59:40 +00:00
Chris Lattner
d1906e2ace
Implement a todo, rewriting all possible scev expressions inside of the
...
loop. This eliminates the extra add from the previous case, but it's
not clear that this will be a performance win overall. Tommorows test
results will tell. :)
llvm-svn: 13103
2004-04-21 23:36:08 +00:00
Chris Lattner
96752d27f4
This code really wants to iterate over the OPERANDS of an instruction, not
...
over its USES. If it's dead it doesn't have any uses! :)
Thanks to the fabulous and mysterious Bill Wendling for pointing this out. :)
llvm-svn: 13102
2004-04-21 22:29:37 +00:00
Chris Lattner
a3e2004609
Implement a fixme. The helps loops that have induction variables of different
...
types in them. Instead of creating an induction variable for all types, it
creates a single induction variable and casts to the other sizes. This generates
this code:
no_exit: ; preds = %entry, %no_exit
%indvar = phi uint [ %indvar.next, %no_exit ], [ 0, %entry ] ; <uint> [#uses=4]
*** %j.0.0 = cast uint %indvar to short ; <short> [#uses=1]
%indvar = cast uint %indvar to int ; <int> [#uses=1]
%tmp.7 = getelementptr short* %P, uint %indvar ; <short*> [#uses=1]
store short %j.0.0, short* %tmp.7
%inc.0 = add int %indvar, 1 ; <int> [#uses=2]
%tmp.2 = setlt int %inc.0, %N ; <bool> [#uses=1]
%indvar.next = add uint %indvar, 1 ; <uint> [#uses=1]
br bool %tmp.2, label %no_exit, label %loopexit
instead of:
no_exit: ; preds = %entry, %no_exit
%indvar = phi ushort [ %indvar.next, %no_exit ], [ 0, %entry ] ; <ushort> [#uses=2]
*** %indvar = phi uint [ %indvar.next, %no_exit ], [ 0, %entry ] ; <uint> [#uses=3]
%indvar = cast uint %indvar to int ; <int> [#uses=1]
%indvar = cast ushort %indvar to short ; <short> [#uses=1]
%tmp.7 = getelementptr short* %P, uint %indvar ; <short*> [#uses=1]
store short %indvar, short* %tmp.7
%inc.0 = add int %indvar, 1 ; <int> [#uses=2]
%tmp.2 = setlt int %inc.0, %N ; <bool> [#uses=1]
%indvar.next = add uint %indvar, 1
*** %indvar.next = add ushort %indvar, 1
br bool %tmp.2, label %no_exit, label %loopexit
This is an improvement in register pressure, but probably doesn't happen that
often.
The more important fix will be to get rid of the redundant add.
llvm-svn: 13101
2004-04-21 22:22:01 +00:00
Chris Lattner
602146eea1
Fix PR325
...
llvm-svn: 13081
2004-04-20 20:26:03 +00:00
Chris Lattner
29f69938e7
Initial checkin of a simple loop unswitching pass. It still needs work,
...
but it's a start, and seems to do it's basic job.
llvm-svn: 13068
2004-04-19 18:07:02 +00:00
Chris Lattner
1849aa8b1f
Add #include
...
llvm-svn: 13057
2004-04-19 03:01:23 +00:00
Chris Lattner
ab6502f058
Move isLoopInvariant to the Loop class
...
llvm-svn: 13051
2004-04-18 22:46:08 +00:00
Chris Lattner
5a0ed18724
Correct rewriting of exit blocks after my last patch
...
llvm-svn: 13048
2004-04-18 22:27:10 +00:00
Chris Lattner
8e42c6f409
Loop exit sets are no longer explicitly held, they are dynamically computed on demand.
...
llvm-svn: 13046
2004-04-18 22:15:13 +00:00
Chris Lattner
7174acca00
Change the ExitBlocks list from being explicitly contained in the Loop
...
structure to being dynamically computed on demand. This makes updating
loop information MUCH easier.
llvm-svn: 13045
2004-04-18 22:14:10 +00:00
Chris Lattner
13140766df
Reduce the unrolling limit
...
llvm-svn: 13040
2004-04-18 18:06:14 +00:00
Chris Lattner
430968ac2f
If the preheader of the loop was the entry block of the function, make sure
...
that the exit block of the loop becomes the new entry block of the function.
This was causing a verifier assertion on 252.eon.
llvm-svn: 13039
2004-04-18 17:38:42 +00:00
Chris Lattner
199b58db3f
Be much more careful about how we update instructions outside of the loop
...
using instructions inside of the loop. This should fix the MishaTest failure
from last night.
llvm-svn: 13038
2004-04-18 17:32:39 +00:00
Chris Lattner
33ec7f2f9f
After unrolling our single basic block loop, fold it into the preheader and exit
...
block. The primary motivation for doing this is that we can now unroll nested loops.
This makes a pretty big difference in some cases. For example, in 183.equake,
we are now beating the native compiler with the CBE, and we are a lot closer
with LLC.
I'm now going to play around a bit with the unroll factor and see what effect
it really has.
llvm-svn: 13034
2004-04-18 06:27:43 +00:00
Chris Lattner
f2045a8c05
Fix a bug: this does not preserve the CFG!
...
While we're at it, add support for updating loop information correctly.
llvm-svn: 13033
2004-04-18 05:38:37 +00:00
Chris Lattner
b0d23bf99d
Initial checkin of a simple loop unroller. This pass is extremely basic and
...
limited. Even in it's extremely simple state (it can only *fully* unroll single
basic block loops that execute a constant number of times), it already helps improve
performance a LOT on some benchmarks, particularly with the native code generators.
llvm-svn: 13028
2004-04-18 05:20:17 +00:00
Chris Lattner
e0f56972f0
Make the tail duplication threshold accessible from the command line instead of hardcoded
...
llvm-svn: 13025
2004-04-18 00:52:43 +00:00
Chris Lattner
740ae78ae6
If the loop executes a constant number of times, try a bit harder to replace
...
exit values.
llvm-svn: 13018
2004-04-17 18:44:09 +00:00
Chris Lattner
bcb690dc9b
Fix a HUGE pessimization on X86. The indvars pass was taking this
...
(familiar) function:
int _strlen(const char *str) {
int len = 0;
while (*str++) len++;
return len;
}
And transforming it to use a ulong induction variable, because the type of
the pointer index was left as a constant long. This is obviously very bad.
The fix is to shrink long constants in getelementptr instructions to intptr_t,
making the indvars pass insert a uint induction variable, which is much more
efficient.
Here's the before code for this function:
int %_strlen(sbyte* %str) {
entry:
%tmp.13 = load sbyte* %str ; <sbyte> [#uses=1]
%tmp.24 = seteq sbyte %tmp.13, 0 ; <bool> [#uses=1]
br bool %tmp.24, label %loopexit, label %no_exit
no_exit: ; preds = %entry, %no_exit
*** %indvar = phi uint [ %indvar.next, %no_exit ], [ 0, %entry ] ; <uint> [#uses=2]
*** %indvar = phi ulong [ %indvar.next, %no_exit ], [ 0, %entry ] ; <ulong> [#uses=2]
%indvar1 = cast ulong %indvar to uint ; <uint> [#uses=1]
%inc.02.sum = add uint %indvar1, 1 ; <uint> [#uses=1]
%inc.0.0 = getelementptr sbyte* %str, uint %inc.02.sum ; <sbyte*> [#uses=1]
%tmp.1 = load sbyte* %inc.0.0 ; <sbyte> [#uses=1]
%tmp.2 = seteq sbyte %tmp.1, 0 ; <bool> [#uses=1]
%indvar.next = add ulong %indvar, 1 ; <ulong> [#uses=1]
%indvar.next = add uint %indvar, 1 ; <uint> [#uses=1]
br bool %tmp.2, label %loopexit.loopexit, label %no_exit
loopexit.loopexit: ; preds = %no_exit
%indvar = cast uint %indvar to int ; <int> [#uses=1]
%inc.1 = add int %indvar, 1 ; <int> [#uses=1]
ret int %inc.1
loopexit: ; preds = %entry
ret int 0
}
Here's the after code:
int %_strlen(sbyte* %str) {
entry:
%inc.02 = getelementptr sbyte* %str, uint 1 ; <sbyte*> [#uses=1]
%tmp.13 = load sbyte* %str ; <sbyte> [#uses=1]
%tmp.24 = seteq sbyte %tmp.13, 0 ; <bool> [#uses=1]
br bool %tmp.24, label %loopexit, label %no_exit
no_exit: ; preds = %entry, %no_exit
*** %indvar = phi uint [ %indvar.next, %no_exit ], [ 0, %entry ] ; <uint> [#uses=3]
%indvar = cast uint %indvar to int ; <int> [#uses=1]
%inc.0.0 = getelementptr sbyte* %inc.02, uint %indvar ; <sbyte*> [#uses=1]
%inc.1 = add int %indvar, 1 ; <int> [#uses=1]
%tmp.1 = load sbyte* %inc.0.0 ; <sbyte> [#uses=1]
%tmp.2 = seteq sbyte %tmp.1, 0 ; <bool> [#uses=1]
%indvar.next = add uint %indvar, 1 ; <uint> [#uses=1]
br bool %tmp.2, label %loopexit, label %no_exit
loopexit: ; preds = %entry, %no_exit
%len.0.1 = phi int [ 0, %entry ], [ %inc.1, %no_exit ] ; <int> [#uses=1]
ret int %len.0.1
}
llvm-svn: 13016
2004-04-17 18:16:10 +00:00
Chris Lattner
5c85946417
Even if there are not any induction variables in the loop, if we can compute
...
the trip count for the loop, insert one so that we can canonicalize the exit
condition.
llvm-svn: 13015
2004-04-17 18:08:33 +00:00
Chris Lattner
ed423cc09d
Fix some really nasty dominance bugs that were exposed by my patch to
...
make the verifier more strict. This fixes building zlib
llvm-svn: 13002
2004-04-16 18:08:07 +00:00
Chris Lattner
bc458be5f9
Fix some of the strange CBE-only failures that happened last night.
...
llvm-svn: 12980
2004-04-16 06:03:17 +00:00
Chris Lattner
ac2b465cb4
Fix a bug in the previous checkin: if the exit block is not the same as
...
the back-edge block, we must check the preincremented value.
llvm-svn: 12968
2004-04-15 20:26:22 +00:00
Chris Lattner
dcf2ca93e6
Change the canonical induction variable that we insert.
...
Instead of producing code like this:
Loop:
X = phi 0, X2
...
X2 = X + 1
if (X != N-1) goto Loop
We now generate code that looks like this:
Loop:
X = phi 0, X2
...
X2 = X + 1
if (X2 != N) goto Loop
This has two big advantages:
1. The trip count of the loop is now explicit in the code, allowing
the direct implementation of Loop::getTripCount()
2. This reduces register pressure in the loop, and allows X and X2 to be
put into the same register.
As a consequence of the second point, the code we generate for loops went
from:
.LBB2: # no_exit.1
...
mov %EDI, %ESI
inc %EDI
cmp %ESI, 2
mov %ESI, %EDI
jne .LBB2 # PC rel: no_exit.1
To:
.LBB2: # no_exit.1
...
inc %ESI
cmp %ESI, 3
jne .LBB2 # PC rel: no_exit.1
... which has two fewer moves, and uses one less register.
llvm-svn: 12961
2004-04-15 15:21:43 +00:00
Chris Lattner
6fcf8c7402
ADd a trivial instcombine: load null -> null
...
llvm-svn: 12940
2004-04-14 03:28:36 +00:00
Chris Lattner
545e77c9d5
Add SCCP support for constant folding calls, implementing:
...
test/Regression/Transforms/SCCP/calltest.ll
llvm-svn: 12921
2004-04-13 19:43:54 +00:00
Chris Lattner
8c0e9c95e9
Constant propagation should remove the dead instructions
...
llvm-svn: 12917
2004-04-13 19:28:20 +00:00
Chris Lattner
70f6a0ddcf
Fix LoopSimplify/2004-04-13-LoopSimplifyUpdateDomFrontier.ll
...
LoopSimplify was not updating dominator frontiers correctly in some cases.
llvm-svn: 12890
2004-04-13 16:23:25 +00:00
Chris Lattner
ae63c235f9
Refactor code a bit to make it simpler and eliminate the goto
...
llvm-svn: 12888
2004-04-13 15:21:18 +00:00
Chris Lattner
faf377df58
This patch addresses PR35: Loop simplify should reconstruct nested loops.
...
This is fairly straight-forward, but was a real nightmare to get just
perfect. aarg. :)
llvm-svn: 12884
2004-04-13 05:05:33 +00:00
Chris Lattner
603d821596
Add support for removing invoke instructions
...
llvm-svn: 12858
2004-04-12 05:15:13 +00:00
Chris Lattner
ca1428e01c
Fix a bug in my select transformation
...
llvm-svn: 12826
2004-04-11 01:39:19 +00:00
Chris Lattner
777977bf2e
Update the value numbering interface.
...
llvm-svn: 12824
2004-04-10 22:33:34 +00:00
Chris Lattner
96fca8de3d
Implement InstCombine/select.ll:test13*
...
llvm-svn: 12821
2004-04-10 22:21:27 +00:00
Chris Lattner
618c89d5eb
Implement InstCombine/add.ll:test20
...
Canonicalize add of sign bit constant into a xor
llvm-svn: 12819
2004-04-10 22:01:55 +00:00
Chris Lattner
6d569b52ed
Rewrite the GCSE pass to be *substantially* simpler, a bit more efficient,
...
and a bit more powerful
llvm-svn: 12817
2004-04-10 21:11:11 +00:00
Chris Lattner
22c22de2f0
Fix spurious warning in release mode
...
llvm-svn: 12816
2004-04-10 19:15:56 +00:00
Chris Lattner
924b6c173c
Simplify code a bit, and fix a bug that was breaking perlbmk
...
llvm-svn: 12814
2004-04-10 18:06:21 +00:00
Chris Lattner
f126f03878
Fix a bug in my checkin last night that was breaking programs using invoke.
...
llvm-svn: 12813
2004-04-10 16:53:29 +00:00
Chris Lattner
d4979e2904
Fix previous patch
...
llvm-svn: 12811
2004-04-10 07:27:48 +00:00
Chris Lattner
3b211f0432
Correctly update counters
...
llvm-svn: 12810
2004-04-10 07:02:02 +00:00
Chris Lattner
1676188024
Simplify code a bit, and use alias analysis to allow us to delete unused
...
call and invoke instructions that are known to not write to memory.
llvm-svn: 12807
2004-04-10 06:53:09 +00:00
Chris Lattner
306540a2f4
Implement select.ll:test12*
...
This transforms code like this:
%C = or %A, %B
%D = select %cond, %C, %A
into:
%C = select %cond, %B, 0
%D = or %A, %C
Since B is often a constant, the select can often be eliminated. In any case,
this reduces the usage count of A, allowing subsequent optimizations to happen.
This xform applies when the operator is any of:
add, sub, mul, or, xor, and, shl, shr
llvm-svn: 12800
2004-04-09 23:46:01 +00:00
Chris Lattner
3a6e4b9a35
Fold binary operators with a constant operand into select instructions
...
that have a constant operand. This implements
add.ll:test19, shift.ll:test15*, and others that are not tested
llvm-svn: 12794
2004-04-09 19:05:30 +00:00
Chris Lattner
0e1f5553df
Implement select.ll:test11
...
llvm-svn: 12793
2004-04-09 18:19:44 +00:00
Chris Lattner
0ca3cbfa5e
Implement InstCombine/cast-propagate.ll
...
llvm-svn: 12784
2004-04-08 20:39:49 +00:00