Commit Graph

390 Commits

Author SHA1 Message Date
Reid Spencer 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
Chris Lattner 56273827b1 If we are extracting a block that has multiple successors that are the same
block (common in a switch), make sure to remove extra edges in successor
blocks.  This fixes CodeExtractor/2004-08-12-BlockExtractPHI.ll and should
be pulled into LLVM 1.3 (though the regression test need not be, as that
would require pulling in the LoopExtract.cpp changes).

llvm-svn: 15717
2004-08-13 03:27:07 +00:00
Chris Lattner f06b043204 When we code extract some stuff, leave the codeRepl block in the place where
the extracted code was, instead of putting it at the end of the function

llvm-svn: 15716
2004-08-13 03:17:39 +00:00
Chris Lattner 889d346e6e Add value mapper support for select constant exprs. This should fix a bug
Nate ran into when bugpointing siod.  This fix should go into LLVM 1.3

llvm-svn: 15712
2004-08-13 02:43:19 +00:00
Chris Lattner 7f1c7ede5b Fix code extraction of unwind blocks. This fixed bugs that bugpoint can
run into.  This should go into 1.3

llvm-svn: 15679
2004-08-12 03:17:02 +00:00
Alkis Evlogimenos 832437255d Stop using getValues().
llvm-svn: 15487
2004-08-04 08:44:43 +00:00
Chris Lattner 7471b96a05 Expose this as a functionpass
llvm-svn: 15369
2004-07-31 10:01:58 +00:00
Misha Brukman f4a410f907 Fix #includes of i*.h => Instructions.h as per PR403.
llvm-svn: 15337
2004-07-29 17:30:57 +00:00
Misha Brukman 63b38bd2ed Fix #includes of i*.h => Instructions.h as per PR403.
llvm-svn: 15334
2004-07-29 17:30:56 +00:00
Alkis Evlogimenos fd7a2d4477 Merge i*.h headers into Instructions.h as part of bug403.
llvm-svn: 15325
2004-07-29 12:17:34 +00:00
Brian Gaeke 902dcf0729 These files don't need to include <iostream> since they include "Support/Debug.h".
llvm-svn: 15089
2004-07-21 20:50:33 +00:00
Chris Lattner 45b50d14c9 Fix a serious code pessimization problem. If an inlined function has a single
return, clone the 'ret' BB code into the block AFTER the inlined call, not the
other way around.

llvm-svn: 15030
2004-07-20 05:45:24 +00:00
Chris Lattner 5823ac1c21 Implement SimplifyCFG/BrUnwind.ll
llvm-svn: 15022
2004-07-20 01:17:38 +00:00
Reid Spencer 3b4e83ec83 Remove an if statement that would never be reached.
llvm-svn: 14968
2004-07-18 08:41:47 +00:00
Reid Spencer cb3fb5d4f5 bug 122:
- Replace ConstantPointerRef usage with GlobalValue usage

llvm-svn: 14953
2004-07-18 00:44:37 +00:00
Reid Spencer ef784f01dd bug 122:
- Minimize redundant isa<GlobalValue> usage

llvm-svn: 14948
2004-07-18 00:32:14 +00:00
Chris Lattner 32c518e526 Progress on PR341
llvm-svn: 14840
2004-07-15 02:06:12 +00:00
Reid Spencer eb04d9bcb4 Add #include <iostream> since Value.h does not #include it any more.
llvm-svn: 14622
2004-07-04 12:19:56 +00:00
Misha Brukman 49bb82a4b8 Moved to lib/VMCore
llvm-svn: 14348
2004-06-23 17:21:17 +00:00
Brian Gaeke 1ea8447089 Use new IsNAN() wrapper.
llvm-svn: 14340
2004-06-23 00:25:35 +00:00
Chris Lattner f12c4a3d37 *FINALLY* Fix a really nasty nondeterministic bug that has been haunting us
since May 1st.  In this code, the pred iterator was being invalidated sometimes
causing the wrong entries to be added to PHI nodes.

The fix for this is to defererence and safe the *PI value before we hack on
branch instructions, which changes use/def chains, which SOMETIMES invalidates
the iterator.

llvm-svn: 14278
2004-06-21 07:19:01 +00:00
Chris Lattner 46f60890a3 Comment out the isnan stuff until we get a proper autoconf test for it
breaking the build on sparc is not acceptable.

llvm-svn: 14277
2004-06-21 06:17:21 +00:00
Chris Lattner 9734fd0980 Add some DEBUG output to the simplifycfg routines
Fix another non-deterministic behavior, this one should actually speed up the
code though as it was doing silly things.

llvm-svn: 14258
2004-06-20 01:13:18 +00:00
Chris Lattner 4db0f8260a Change to use the StableBasicBlockNumbering class
llvm-svn: 14247
2004-06-19 08:42:40 +00:00
Chris Lattner a52ab6f57f Do not let the numbering of PHI nodes placed in the function depend on
non-deterministic things like the ordering of blocks in the dominance
frontier of a BB.  Unfortunately, I don't know of a better way to solve
this problem than to explicitly sort the BB's in function-order before
processing them.  This is guaranteed to slow the pass down a bit, but
is absolutely necessary to get usable diffs between two different tools
executing the mem2reg or scalarrepl pass.

Before this, bazillions of spurious diff failures occurred all over the
place due to the different order of processing PHIs:

-       %tmp.111 = getelementptr %struct.Connector_struct* %upcon.0.0, uint 0, uint 0
+       %tmp.111 = getelementptr %struct.Connector_struct* %upcon.0.1, uint 0, uint 0

Now, the diffs match.

llvm-svn: 14244
2004-06-19 07:40:14 +00:00
Chris Lattner b2b151d297 Do not sort by the address of LLVM ConstantInt* objects. This produces
nondeterministic results that depend on where these objects land in memory.
Instead, sort by the value of the constant, which is stable.

Before this patch, the -simplifycfg pass run from two different compilers
could cause different code to be generated, though it was semantically the
same:

@@ -12258,8 +12258,8 @@
        %s_addr.1 = phi sbyte* [ %s, %entry ], [ %inc.0, %no_exit ]             ; <sbyte*> [#uses=5]
        %tmp.1 = load sbyte* %s_addr.1          ; <sbyte> [#uses=1]
        switch sbyte %tmp.1, label %no_exit [
-                sbyte 0, label %loopexit
                 sbyte 46, label %loopexit
+                sbyte 0, label %loopexit
        ]

We need to stomp all of this stuff out.

llvm-svn: 14243
2004-06-19 07:02:14 +00:00
Brian Gaeke 27b13253d9 I love the smell of a freshly broken PowerPC build in the morning.
llvm-svn: 14206
2004-06-17 22:27:04 +00:00
Chris Lattner f03f320b79 Fix compilation problem on freebsd. Problem noted by Vladimir Merzliakov in
PR371

llvm-svn: 14203
2004-06-17 21:20:52 +00:00
Chris Lattner 6b7275996c Rename Type::PrimitiveID to TypeId and ::getPrimitiveID() to ::getTypeID()
llvm-svn: 14201
2004-06-17 18:19:28 +00:00
Brian Gaeke 20e09e5c7b Um, did someone make a typo or something?
llvm-svn: 14192
2004-06-15 23:09:50 +00:00
Chris Lattner 5a542aadc8 Remove support for the isnan intrinsic
llvm-svn: 14186
2004-06-15 21:37:54 +00:00
Brian Gaeke 21370771ba Quick hack to get this file compiling again on Mac OS X. The right thing to do
is write an autoconf macro that checks whether __isnan or isnan actually works
**using the C++ compiler after #include <cmath>**, instead of doing it the easy
way with AC_CHECK_FUNCS().

llvm-svn: 14171
2004-06-14 06:33:19 +00:00
Alkis Evlogimenos e395468ae5 Add constant folding capabilities to the isunordered intrinsic.
llvm-svn: 14168
2004-06-13 01:23:56 +00:00
Chris Lattner ec941f7abb Constant fold the isnan intrinsic
llvm-svn: 14150
2004-06-11 06:16:23 +00:00
Chris Lattner c6e21fbd5c Implement constant folding of fmod, which is used a lot in povray
llvm-svn: 13823
2004-05-27 07:25:00 +00:00
Chris Lattner 06158d140c Restructure call constant folding code a bit to make it simpler
Add support for acos/asin/atan.  188.ammp contains three calls to acos with
constant arguments.  Constant folding it allows elimination of those 3 calls
and three FP divisions of the results.

llvm-svn: 13821
2004-05-27 06:26:28 +00:00
Alkis Evlogimenos 0eefdcd73f Do not pass a null pointer if this instruction is not prepended or
appended anywhere.

llvm-svn: 13798
2004-05-26 22:50:28 +00:00
Alkis Evlogimenos 9e84b503f0 Use one destination constructor for the unconditional branch.
llvm-svn: 13792
2004-05-26 21:38:14 +00:00
Reid Spencer e7e9671cad Convert to SymbolTable's new iteration interface.
llvm-svn: 13754
2004-05-25 08:53:40 +00:00
Reid Spencer abb6f008ca Convert to SymbolTable's new lookup and iteration interfaces.
llvm-svn: 13751
2004-05-25 08:52:20 +00:00
Brian Gaeke 72185765bc Add CloneTraceInto(), which is based on (and has mostly the same
effects as) CloneFunctionInto().

llvm-svn: 13601
2004-05-19 09:08:14 +00:00
Brian Gaeke 6182acf92a Move RemapInstruction() to ValueMapper, so that it can be shared with
CloneTrace, and because it is primarily an operation on ValueMaps.  It
is now a global (non-static) function which can be pulled in using
ValueMapper.h.

llvm-svn: 13600
2004-05-19 09:08:12 +00:00
Chris Lattner 66219abac7 Do not pass in the same argument to the extracted function more than once, and
give the extracted function a more useful name than just foo_code.

llvm-svn: 13493
2004-05-12 16:26:18 +00:00
Chris Lattner 13d2ddfe9c Implement support for code extracting basic blocks that have a return
instruction in them.

llvm-svn: 13490
2004-05-12 16:07:41 +00:00
Chris Lattner 795c9933e2 Implement splitting of PHI nodes, allowing block extraction of BB's that have
PHI node entries from multiple outside-the-region blocks.  This also fixes
extraction of the entry block in a function.  Yaay.

This has successfully block extracted all (but one) block from the score_move
function in obsequi (out of 33).  Hrm, I wonder which block the bug is in.  :)

llvm-svn: 13489
2004-05-12 15:29:13 +00:00
Chris Lattner 3b2917bfcf * Pull some code out into the definedInRegion/definedInCaller methods
* Add a stub for the severSplitPHINodes which will allow us to bbextract
  bb's with PHI nodes in them soon.
* Remove unused arguments from findInputsOutputs
* Dramatically simplify the code in findInputsOutputs.  In particular,
  nothing really cares whether or not a PHI node is using something.
* Move moveCodeToFunction to after emitCallAndSwitchStatement as that's the
  order they get called.
* Fix a bug where we would code extract a region that included a call to
  vastart.  Like 'alloca', calls to vastart must stay in the function that
  they are defined in.
* Add some comments.

llvm-svn: 13482
2004-05-12 06:01:40 +00:00
Chris Lattner ffc4926263 Generate substantially better code when there are a limited number of exits
from the extracted region.  If the return has 0 or 1 exit blocks, the new
function returns void.  If it has 2 exits, it returns bool, otherwise it
returns a ushort as before.

This allows us to use a conditional branch instruction when there are two
exit blocks, as often happens during block extraction.

llvm-svn: 13481
2004-05-12 04:14:24 +00:00
Chris Lattner 3d1ca67fdd Two minor improvements:
1. Get rid of the silly abort block.  When doing bb extraction, we get one
     abort block for every block extracted, which is kinda annoying.
  2. If the switch ends up having a single destination, turn it into an
     unconditional branch.

I would like to add support for conditional branches, but to do this we will
want to have the function return a bool instead of a ushort.

llvm-svn: 13478
2004-05-12 03:22:33 +00:00
Chris Lattner be6f06818c Do not clone arbitrary condition instructions.
llvm-svn: 13316
2004-05-02 05:19:36 +00:00
Chris Lattner 51a6dbcb65 Do not infinitely "unroll" single BB loops.
llvm-svn: 13315
2004-05-02 05:02:03 +00:00
Chris Lattner 1e94ed606e Dont' merge terminators that are needed to select PHI node values.
llvm-svn: 13312
2004-05-02 01:00:44 +00:00
Chris Lattner 2e93c4275e Implement SimplifyCFG/branch-cond-merge.ll
Turning "if (A < B && B < C)" into "if (A < B & B < C)"

llvm-svn: 13311
2004-05-01 23:35:43 +00:00
Chris Lattner 4cbd160b45 Fix my missing parens
llvm-svn: 13307
2004-05-01 22:41:51 +00:00
Chris Lattner 88da6f7b52 Implement SimplifyCFG/branch-cond-prop.ll
llvm-svn: 13306
2004-05-01 22:36:37 +00:00
Misha Brukman 3596f0a180 * Allow aggregating extracted function arguments (controlled by flag)
* Commandline option (for now) controls that flag that is passed in

llvm-svn: 13141
2004-04-23 23:54:17 +00:00
Alkis Evlogimenos f68f40ea42 Include cerrno (gcc-3.4 fix)
llvm-svn: 13091
2004-04-21 16:11:40 +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
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 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 ca52d0468e Add a simple call constant propagation interface.
llvm-svn: 12919
2004-04-13 19:28:52 +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 3b3861d305 Implement ScalarRepl/select_promote.ll
llvm-svn: 12779
2004-04-08 19:59:34 +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 709f03e2dd Fix linking of constant expr casts due to type resolution changes. With
this and the other patches 253.perlbmk links again.

llvm-svn: 12565
2004-03-31 02:58:28 +00:00
Chris Lattner 81bdcb90ce Now that all the code generators support the select instruction, and the instcombine
pass can eliminate many nasty cases of them, start generating them in the optimizers

llvm-svn: 12545
2004-03-30 19:44:05 +00:00
Chris Lattner 232155dc1b Fix bug: CodeExtractor/2004-03-17-MissedLiveIns.ll
With this fix we now successfully extract all 149 loops from 256.bzip2 without
crashing or miscompiling the program!

llvm-svn: 12493
2004-03-18 05:56:32 +00:00
Chris Lattner acd75986ee Fix CodeExtractor/2004-03-17-UpdatePHIsOutsideRegion.ll
llvm-svn: 12489
2004-03-18 05:38:31 +00:00
Chris Lattner 320d59f4cd Seriously simplify and correct the PHI node handling code.
llvm-svn: 12487
2004-03-18 05:28:49 +00:00
Chris Lattner d8017a340d Fix CodeExtractor/2004-03-17-OutputMismatch.ll
llvm-svn: 12486
2004-03-18 04:12:05 +00:00
Chris Lattner 37de257ef0 Fix several bugs in the extractor:
1. Names were not put on the new arguments created (ok, this just helps sanity :)
2. Fix outgoing pointer values
3. Do not insert stores for values that had not been computed
4. Fix some wierd problems with the outset calculation

This fixes CodeExtractor/2004-03-14-DominanceProblem.ll, making the extractor
work on at least one simple case!

llvm-svn: 12484
2004-03-18 03:49:40 +00:00
Chris Lattner cee3404d0a Prune #includes, moving the module interface to the front. Note that this
exposed the fact that the header was not self-contained.  There is a reason
we do things :)

llvm-svn: 12481
2004-03-18 03:15:29 +00:00
Chris Lattner a078f47b39 Fix compilation of mesa, which I broke earlier today
llvm-svn: 12465
2004-03-17 02:02:47 +00:00
Chris Lattner bb1a2cc7ab This code was both incredibly complex and incredibly broken. Fix it.
llvm-svn: 12456
2004-03-16 23:23:11 +00:00
Chris Lattner a64923ad26 Do not copy gigantic switch instructions
llvm-svn: 12441
2004-03-16 19:45:22 +00:00
Chris Lattner fb87cdecd8 Mostly cosmetic improvements. Do fix the bug where a global value was considered an input.
llvm-svn: 12406
2004-03-15 01:26:44 +00:00
Chris Lattner 73ab1fa7c8 Assert that input blocks meet the invariants we expect
Simplify the input/output finder.  All elements of a basic block are
instructions.  Any used arguments are also inputs.  An instruction can only
be used by another instruction.

llvm-svn: 12405
2004-03-15 01:18:23 +00:00
Chris Lattner 5b2072ecd3 No correctness fixes here, just minor qoi fixes:
* Don't insert a branch to the switch instruction after the call, just
  make it a single block.
* Insert the new alloca instructions in the entry block of the original
  function instead of having them execute dynamically
* Don't make the default edge of the switch instruction go back to the switch.
  The loop extractor shouldn't create new loops!
* Give meaningful names to the alloca slots and the reload instructions
* Some minor code simplifications

llvm-svn: 12402
2004-03-14 23:43:24 +00:00
Chris Lattner b4d8bf365c Simplify code a bit, and fix bug CodeExtractor/2004-03-14-NoSwitchSupport.ll
This also implements a two minor improvements:
  * Don't insert live-out stores IN the region, insert them on the code path
    that exits the region
  * If the region is exited to the same block from multiple paths, share the
    switch statement entry, live-out store code, and the basic block.

llvm-svn: 12401
2004-03-14 23:05:49 +00:00
Chris Lattner 9c431f6c44 Simplify the code a bit by making the collection of basic blocks to extract
a member of the class.  While we're at it, turn the collection into a set
instead of a vector to improve efficiency and make queries simpler.

llvm-svn: 12400
2004-03-14 22:34:55 +00:00
Chris Lattner 4fca71eb44 Minor random cleanups
llvm-svn: 12382
2004-03-14 04:01:47 +00:00
Chris Lattner 3684469326 Verify functions as they are produced if -debug is specified. Reduce
curly braceage

llvm-svn: 12378
2004-03-14 03:17:22 +00:00
Chris Lattner 41ec709e00 Move to the IPO library. Utils shouldn't contain passes.
llvm-svn: 12372
2004-03-14 02:32:27 +00:00
Chris Lattner 8eebc49884 DemoteRegToStack got moved from DemoteRegToStack.h to Local.h
llvm-svn: 12368
2004-03-14 02:13:38 +00:00
Chris Lattner cb015ee6c0 Add constant folding wrapper support for select instructions.
llvm-svn: 12319
2004-03-12 05:53:03 +00:00
Misha Brukman f44acae31e Implement ExtractCodeRegion()
llvm-svn: 12070
2004-03-02 00:20:57 +00:00
Misha Brukman f272f9b3d5 Make a note that this is usually used via bugpoint.
llvm-svn: 12068
2004-03-02 00:19:09 +00:00
Misha Brukman 5af2be7d09 * Add implementation of ExtractBasicBlock()
* Add comments to ExtractLoop()

llvm-svn: 12053
2004-03-01 18:28:34 +00:00
Chris Lattner 2de229f31b Fix bug: test/Regression/Transforms/LowerInvoke/2004-02-29-PHICrash.llx
... which tickled the lowerinvoke pass because it used the BCE routines.

llvm-svn: 12012
2004-02-29 22:24:41 +00:00
Chris Lattner d3e6ae263c Implement switch->br and br->switch folding by ripping out the switch->switch
and br->br code and generalizing it.  This allows us to compile code like this:

int test(Instruction *I) {
  if (isa<CastInst>(I))
    return foo(7);
  else if (isa<BranchInst>(I))
    return foo(123);
  else if (isa<UnwindInst>(I))
    return foo(1241);
  else if (isa<SetCondInst>(I))
    return foo(1);
  else if (isa<VAArgInst>(I))
    return foo(42);
  return foo(-1);
}

into:

int %_Z4testPN4llvm11InstructionE("struct.llvm::Instruction"* %I) {
entry:
        %tmp.1.i.i.i.i.i.i.i = getelementptr "struct.llvm::Instruction"* %I, long 0, ubyte 4            ; <uint*> [#uses=1]
        %tmp.2.i.i.i.i.i.i.i = load uint* %tmp.1.i.i.i.i.i.i.i          ; <uint> [#uses=2]
        %tmp.2.i.i.i.i.i.i = seteq uint %tmp.2.i.i.i.i.i.i.i, 27                ; <bool> [#uses=0]
        switch uint %tmp.2.i.i.i.i.i.i.i, label %endif.0 [
                 uint 27, label %then.0
                 uint 2, label %then.1
                 uint 5, label %then.2
                 uint 14, label %then.3
                 uint 15, label %then.3
                 uint 16, label %then.3
                 uint 17, label %then.3
                 uint 18, label %then.3
                 uint 19, label %then.3
                 uint 32, label %then.4
        ]
...

As well as handling the cases in 176.gcc and many other programs more effectively.

llvm-svn: 11964
2004-02-28 21:28:10 +00:00
Misha Brukman 8a2c28fdda Right, it's really Extractor, not Extraction.
llvm-svn: 11939
2004-02-28 03:37:58 +00:00
Misha Brukman 03a11340ff A pass that uses the generic CodeExtractor to rip out *every* loop in every
function, as long as the loop isn't the only one in that function. This should
help debugging passes easier with BugPoint.

llvm-svn: 11936
2004-02-28 03:33:01 +00:00
Misha Brukman caa1a5abeb A generic code extractor: given a list of BasicBlocks, it will rip them out into
a new function, taking care of inputs and outputs.

llvm-svn: 11935
2004-02-28 03:26:20 +00:00
Chris Lattner 21e941fbfd turn things like:
if (X == 0 || X == 2)

...where the comparisons and branches are in different blocks... into a switch
instruction.  This comes up a lot in various programs, and works well with
the switch/switch merging code I checked earlier.  For example, this testcase:

int switchtest(int C) {
  return C == 0 ? f(123) :
         C == 1 ? f(3123) :
         C == 4 ? f(312) :
         C == 5 ? f(1234): f(444);
}

is converted into this:
        switch int %C, label %cond_false.3 [
                 int 0, label %cond_true.0
                 int 1, label %cond_true.1
                 int 4, label %cond_true.2
                 int 5, label %cond_true.3
        ]

instead of a whole bunch of conditional branches.

Admittedly the code is ugly, and incomplete.  To be complete, we need to add
br -> switch merging and switch -> br merging.  For example, this testcase:

struct foo { int Q, R, Z; };
#define A (X->Q+X->R * 123)
int test(struct foo *X) {
  return A  == 123 ? X1() :
        A == 12321 ? X2():
        (A == 111 || A == 222) ? X3() :
        A == 875 ? X4() : X5();
}

Gets compiled to this:
        switch int %tmp.7, label %cond_false.2 [
                 int 123, label %cond_true.0
                 int 12321, label %cond_true.1
                 int 111, label %cond_true.2
                 int 222, label %cond_true.2
        ]
...
cond_false.2:           ; preds = %entry
        %tmp.52 = seteq int %tmp.7, 875         ; <bool> [#uses=1]
        br bool %tmp.52, label %cond_true.3, label %cond_false.3

where the branch could be folded into the switch.

This kind of thing occurs *ALL OF THE TIME*, especially in programs like
176.gcc, which is a horrible mess of code.  It contains stuff like *shudder*:

#define SWITCH_TAKES_ARG(CHAR) \
  (   (CHAR) == 'D' \
   || (CHAR) == 'U' \
   || (CHAR) == 'o' \
   || (CHAR) == 'e' \
   || (CHAR) == 'u' \
   || (CHAR) == 'I' \
   || (CHAR) == 'm' \
   || (CHAR) == 'L' \
   || (CHAR) == 'A' \
   || (CHAR) == 'h' \
   || (CHAR) == 'z')

and

#define CONST_OK_FOR_LETTER_P(VALUE, C)                 \
  ((C) == 'I' ? SMALL_INTVAL (VALUE)                    \
   : (C) == 'J' ? SMALL_INTVAL (-(VALUE))               \
   : (C) == 'K' ? (unsigned)(VALUE) < 32                \
   : (C) == 'L' ? ((VALUE) & 0xffff) == 0               \
   : (C) == 'M' ? integer_ok_for_set (VALUE)            \
   : (C) == 'N' ? (VALUE) < 0                           \
   : (C) == 'O' ? (VALUE) == 0                          \
   : (C) == 'P' ? (VALUE) >= 0                          \
   : 0)

and

#define LEGITIMIZE_ADDRESS(X,OLDX,MODE,WIN)                     \
{                                                               \
  if (GET_CODE (X) == PLUS && CONSTANT_ADDRESS_P (XEXP (X, 1))) \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 0),                   \
                   copy_to_mode_reg (SImode, XEXP (X, 1)));     \
  if (GET_CODE (X) == PLUS && CONSTANT_ADDRESS_P (XEXP (X, 0))) \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 1),                   \
                   copy_to_mode_reg (SImode, XEXP (X, 0)));     \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 0)) == MULT)   \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 1),                   \
                   force_operand (XEXP (X, 0), 0));             \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == MULT)   \
    (X) = gen_rtx (PLUS, SImode, XEXP (X, 0),                   \
                   force_operand (XEXP (X, 1), 0));             \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 0)) == PLUS)   \
    (X) = gen_rtx (PLUS, Pmode, force_operand (XEXP (X, 0), NULL_RTX),\
                   XEXP (X, 1));                                \
  if (GET_CODE (X) == PLUS && GET_CODE (XEXP (X, 1)) == PLUS)   \
    (X) = gen_rtx (PLUS, Pmode, XEXP (X, 0),                    \
                   force_operand (XEXP (X, 1), NULL_RTX));      \
  if (GET_CODE (X) == SYMBOL_REF || GET_CODE (X) == CONST       \
           || GET_CODE (X) == LABEL_REF)                        \
    (X) = legitimize_address (flag_pic, X, 0, 0);               \
  if (memory_address_p (MODE, X))                               \
    goto WIN; }

and others.  These macros get used multiple times of course.  These are such
lovely candidates for macros, aren't they?  :)

This code also nicely handles LLVM constructs that look like this:

  if (isa<CastInst>(I))
   ...
  else if (isa<BranchInst>(I))
   ...
  else if (isa<SetCondInst>(I))
   ...
  else if (isa<UnwindInst>(I))
   ...
  else if (isa<VAArgInst>(I))
   ...

where the isa can obviously be a dyn_cast as well.  Switch instructions are a
good thing.

llvm-svn: 11870
2004-02-26 07:13:46 +00:00
Chris Lattner 90ea78edba If a block is made dead, make sure to promptly remove it.
llvm-svn: 11799
2004-02-24 16:09:21 +00:00
Chris Lattner a2ab489135 Implement SimplifyCFG/switch_switch_fold.ll
This case occurs many times in various benchmarks, especially when combined
with the previous patch.  This allows it to get stuff like:
  if (X == 4 || X == 3)
    if (X == 5 || X == 8)

and

switch (X) {
case 4: case 5: case 6:
  if (X == 4 || X == 5)

llvm-svn: 11797
2004-02-24 07:23:58 +00:00
Chris Lattner 3cd98f054a Rearrange code a bit
llvm-svn: 11793
2004-02-24 05:54:22 +00:00
Chris Lattner 6f4b45acf5 Implement: test/Regression/Transforms/SimplifyCFG/switch_create.ll
This turns code like this:
  if (X == 4 | X == 7)
and
  if (X != 4 & X != 7)
into switch instructions.

llvm-svn: 11792
2004-02-24 05:38:11 +00:00
Chris Lattner 693e393fee Fix PR245: Linking weak and strong global variables is dependent on link order
llvm-svn: 11565
2004-02-17 21:56:04 +00:00