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Author SHA1 Message Date
Chris Lattner
a814080025 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
1e9ac1a45e 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
885a6eb74d 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
a43312d30b Add support for evaluation of exp/log/log10/pow 
llvm-svn: 13011
 2004-04-16 22:35:33 +00:00
Chris Lattner
284d3b0311 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
Brian Gaeke
174633b078 Include <cmath> for compatibility with gcc 3.0.x (the system compiler on 
Debian.)

llvm-svn: 12986
 2004-04-16 15:57:32 +00:00
Chris Lattner
9e9b2b7474 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
0328d75c83 Fix Inline/2004-04-15-InlineDeletesCall.ll 
Basically we were using SimplifyCFG as a huge sledgehammer for a simple
optimization.  Because simplifycfg does so many things, we can't use it
for this purpose.

llvm-svn: 12977
 2004-04-16 05:17:59 +00:00
Chris Lattner
d7a559e353 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
0cec5cb92c 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
6679e46b59 ADd a trivial instcombine: load null -> null 
llvm-svn: 12940
 2004-04-14 03:28:36 +00:00
Chris Lattner
ff9362a8da 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
ca52d0468e Add a simple call constant propagation interface. 
llvm-svn: 12919
 2004-04-13 19:28:52 +00:00
Chris Lattner
d0dc6d5295 Constant propagation should remove the dead instructions 
llvm-svn: 12917
 2004-04-13 19:28:20 +00:00
Chris Lattner
89e959bb1f 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
a6e22814ab 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
8417052938 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
be43544429 Actually update the call graph as the inliner changes it. This allows us to 
execute other CallGraphSCCPasses after the inliner without crashing.

llvm-svn: 12861
 2004-04-12 05:37:29 +00:00
Chris Lattner
494a685449 Add support for removing invoke instructions 
llvm-svn: 12858
 2004-04-12 05:15:13 +00:00
Chris Lattner
08f201bee5 Stop printing Function* 
llvm-svn: 12857
 2004-04-12 04:06:56 +00:00
Chris Lattner
d041dcd92f Simplify code a bit, and be sure to mark the external node as potentially throwing 
llvm-svn: 12856
 2004-04-12 04:06:38 +00:00
Chris Lattner
24cf0200c7 Fix a bug in my select transformation 
llvm-svn: 12826
 2004-04-11 01:39:19 +00:00
Chris Lattner
f16fe7206c Update the value numbering interface. 
llvm-svn: 12824
 2004-04-10 22:33:34 +00:00
Chris Lattner
623fba1107 Implement InstCombine/select.ll:test13* 
llvm-svn: 12821
 2004-04-10 22:21:27 +00:00
Chris Lattner
cf4a996cba 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
69c4900512 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
f9d9665138 Fix spurious warning in release mode 
llvm-svn: 12816
 2004-04-10 19:15:56 +00:00
Chris Lattner
d95ef7eff0 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
7ebfe61dc1 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
5093213c40 Fix previous patch 
llvm-svn: 12811
 2004-04-10 07:27:48 +00:00
Chris Lattner
6149ac8991 Correctly update counters 
llvm-svn: 12810
 2004-04-10 07:02:02 +00:00
Chris Lattner
cfa1adcdb8 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
56e4d3d8ad 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
0aa565647c Fold code like: 
if (C)
    V1 |= V2;

into:
  Vx = V1 | V2;
  V1 = select C, V1, Vx

when the expression can be evaluated unconditionally and is *cheap* to
execute.  This limited form of if conversion is quite handy in lots of cases.
For example, it turns this testcase into straight-line code:

int in0 ; int in1 ; int in2 ; int in3 ;
int in4 ; int in5 ; int in6 ; int in7 ;
int in8 ; int in9 ; int in10; int in11;
int in12; int in13; int in14; int in15;
long output;

void mux(void) {
  output =
      (in0   ?  0x00000001 : 0) | (in1   ?  0x00000002 : 0) |
      (in2   ?  0x00000004 : 0) | (in3   ?  0x00000008 : 0) |
      (in4   ?  0x00000010 : 0) | (in5   ?  0x00000020 : 0) |
      (in6   ?  0x00000040 : 0) | (in7   ?  0x00000080 : 0) |
      (in8   ?  0x00000100 : 0) | (in9   ?  0x00000200 : 0) |
      (in10  ?  0x00000400 : 0) | (in11  ?  0x00000800 : 0) |
      (in12  ?  0x00001000 : 0) | (in13  ?  0x00002000 : 0) |
      (in14  ?  0x00004000 : 0) | (in15  ?  0x00008000 : 0) ;
}

llvm-svn: 12798
 2004-04-09 22:50:22 +00:00
Chris Lattner
183b336a54 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
cf7baf3519 Implement select.ll:test11 
llvm-svn: 12793
 2004-04-09 18:19:44 +00:00
Chris Lattner
e228ee5870 Implement InstCombine/cast-propagate.ll 
llvm-svn: 12784
 2004-04-08 20:39:49 +00:00
Chris Lattner
3b3861d305 Implement ScalarRepl/select_promote.ll 
llvm-svn: 12779
 2004-04-08 19:59:34 +00:00
Chris Lattner
4d25c86b52 Remove the "really gross hacks" that are there to deal with recursive functions. 
Now we collect all of the call sites we are interested in inlining, then inline
them.  This entirely avoids issues with trying to inline a call site we got by
inlining another call site.  This also eliminates iterator invalidation issues.

llvm-svn: 12770
 2004-04-08 06:34:31 +00:00
Chris Lattner
1c631e813d Implement InstCombine/select.ll:test[7-10] 
llvm-svn: 12769
 2004-04-08 04:43:23 +00:00
Chris Lattner
2b2412d0c8 Implement test/Regression/Transforms/InstCombine/getelementptr_index.ll 
llvm-svn: 12762
 2004-04-07 18:38:20 +00:00
Chris Lattner
4d1fcf1dcd Fix a bug in yesterdays checkins which broke siod. siod is a great testcase! :) 
llvm-svn: 12659
 2004-04-05 16:02:41 +00:00
Chris Lattner
8953b90aaa Fix InstCombine/2004-04-04-InstCombineReplaceAllUsesWith.ll 
llvm-svn: 12658
 2004-04-05 02:10:19 +00:00
Chris Lattner
69193f93b6 Support getelementptr instructions which use uint's to index into structure 
types and can have arbitrary 32- and 64-bit integer types indexing into
sequential types.

llvm-svn: 12653
 2004-04-05 01:30:19 +00:00
Chris Lattner
e61b67d7d5 Rewrite the indvars pass to use the ScalarEvolution analysis. 
This also implements some new features for the indvars pass, including
linear function test replacement, exit value substitution, and it works with
a much more general class of induction variables and loops.

llvm-svn: 12620
 2004-04-02 20:24:31 +00:00
Chris Lattner
eed034bcd3 Fix the obvious bug in my previous checkin 
llvm-svn: 12618
 2004-04-02 18:15:10 +00:00
Chris Lattner
9f0db32625 Implement Transforms/SimplifyCFG/return-merge.ll 
This actually causes us to turn code like:

  return C ? A : B;

into a select instruction.

llvm-svn: 12617
 2004-04-02 18:13:43 +00:00
Chris Lattner
c24019c825 Fix PR310 and TailDup/2004-04-01-DemoteRegToStack.llx 
llvm-svn: 12597
 2004-04-01 20:28:45 +00:00
Chris Lattner
59fdf74968 Remove some assertions that are now bogus with the last patch I put in 
llvm-svn: 12595
 2004-04-01 19:21:46 +00:00
Chris Lattner
146d0df5e4 Fix PR306: Loop simplify incorrectly updates dominator information 
Testcase: LoopSimplify/2004-04-01-IncorrectDomUpdate.ll

llvm-svn: 12592
 2004-04-01 19:06:07 +00:00