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163 Commits

Author SHA1 Message Date
Chris Lattner 03c4953cdd rename Type::isIntegral to Type::isInteger, eliminating the old Type::isInteger. 
rename Type::getIntegralTypeMask to Type::getIntegerTypeMask.

This makes naming much more consistent.  For example, there are now no longer any
instances of IntegerType that are not considered isInteger! :)

llvm-svn: 33225
 2007-01-15 02:27:26 +00:00
Chris Lattner 1942249c5b Eliminate calls to isInteger, generalizing code and tightening checks as needed. 
llvm-svn: 33218
 2007-01-15 01:55:30 +00:00
Reid Spencer cddc9dfe97 Implement review feedback for the ConstantBool->ConstantInt merge. Chris 
recommended that getBoolValue be replaced with getZExtValue and that
get(bool) be replaced by get(const Type*, uint64_t). This implements
those changes.

llvm-svn: 33110
 2007-01-12 04:24:46 +00:00
Reid Spencer 542964f55b Rename BoolTy as Int1Ty. Patch by Sheng Zhou. 
llvm-svn: 33076
 2007-01-11 18:21:29 +00:00
Zhou Sheng 75b871fb1e For PR1043: 
Merge ConstantIntegral and ConstantBool into ConstantInt.
Remove ConstantIntegral and ConstantBool from LLVM.

llvm-svn: 33073
 2007-01-11 12:24:14 +00:00
Reid Spencer 266e42b312 For PR950: 
This patch removes the SetCC instructions and replaces them with the ICmp
and FCmp instructions. The SetCondInst instruction has been removed and
been replaced with ICmpInst and FCmpInst.

llvm-svn: 32751
 2006-12-23 06:05:41 +00:00
Reid Spencer 6c38f0bb07 For PR950: 
The long awaited CAST patch. This introduces 12 new instructions into LLVM
to replace the cast instruction. Corresponding changes throughout LLVM are
provided. This passes llvm-test, llvm/test, and SPEC CPUINT2000 with the
exception of 175.vpr which fails only on a slight floating point output
difference.

llvm-svn: 31931
 2006-11-27 01:05:10 +00:00
Bill Wendling 4ae401074c Remove #include <iostream> and use llvm_* streams instead. 
llvm-svn: 31925
 2006-11-26 10:17:54 +00:00
Chris Lattner 95adf8f1da Do not convert massive blocks on phi nodes into select statements. Instead 
only do these transformations if there are a small number of phi's.
This speeds up Ptrdist/ks from 2.35s to 2.19s on my mac pro.

llvm-svn: 31853
 2006-11-18 19:19:36 +00:00
Reid Spencer fdff938a7e For PR950: 
This patch converts the old SHR instruction into two instructions,
AShr (Arithmetic) and LShr (Logical). The Shr instructions now are not
dependent on the sign of their operands.

llvm-svn: 31542
 2006-11-08 06:47:33 +00:00
Reid Spencer de46e48420 For PR786: 
Turn on -Wunused and -Wno-unused-parameter. Clean up most of the resulting
fall out by removing unused variables. Remaining warnings have to do with
unused functions (I didn't want to delete code without review) and unused
variables in generated code. Maintainers should clean up the remaining
issues when they see them. All changes pass DejaGnu tests and Olden.

llvm-svn: 31380
 2006-11-02 20:25:50 +00:00
Chris Lattner fc519cd2d1 Fix SimplifyCFG/2006-10-29-InvokeCrash.ll, a crash compiling QT. 
llvm-svn: 31284
 2006-10-29 21:21:20 +00:00
Reid Spencer e0fc4dfc22 For PR950: 
This patch implements the first increment for the Signless Types feature.
All changes pertain to removing the ConstantSInt and ConstantUInt classes
in favor of just using ConstantInt.

llvm-svn: 31063
 2006-10-20 07:07:24 +00:00
Chris Lattner b8b11599dd Fix SimplifyCFG/2006-10-19-UncondDiv.ll by disabling a bad xform. 
llvm-svn: 31061
 2006-10-20 00:42:07 +00:00
Chris Lattner c9009d917d Fix PR867 (and maybe 868) and testcsae: 
Transforms/SimplifyCFG/2006-08-03-Crash.ll

llvm-svn: 29515
 2006-08-03 21:40:24 +00:00
Chris Lattner b5c9d7a0af Fix an infinite loop on Transforms/SimplifyCFG/2006-06-12-InfLoop.ll 
llvm-svn: 28758
 2006-06-12 20:18:01 +00:00
Chris Lattner 35515557c7 remove some dead code identified by coverity 
llvm-svn: 28289
 2006-05-14 18:45:44 +00:00
Chris Lattner 3237da073e remove dead variables 
llvm-svn: 28286
 2006-05-14 18:33:57 +00:00
Chris Lattner d95665188b Fix Transforms/SimplifyCFG/2006-02-17-InfiniteUnroll.ll 
llvm-svn: 26275
 2006-02-18 00:33:17 +00:00
Chris Lattner 469640e506 Add explicit #includes of <iostream> 
llvm-svn: 25509
 2006-01-22 22:53:01 +00:00
Chris Lattner 2820b8c855 Fix SimplifyCFG/2005-12-03-IncorrectPHIFold.ll 
llvm-svn: 24581
 2005-12-03 18:25:58 +00:00
Chris Lattner 4c3b2b536c Clean up the code a bit. Use isInstructionTriviallyDead to be more aggressive 
and more correct than use_empty().  This fixes PR635 and
SimplifyCFG/2005-10-02-InvokeSimplify.ll

llvm-svn: 23616
 2005-10-03 23:43:43 +00:00
Chris Lattner 499e33646e remove some debugging code 
llvm-svn: 23411
 2005-09-23 18:49:09 +00:00
Chris Lattner c59a371d45 Fold two consequtive branches that share a common destination between them. 
This implements SimplifyCFG/branch-fold.ll, and is useful on ?:/min/max heavy
code

llvm-svn: 23410
 2005-09-23 18:47:20 +00:00
Chris Lattner 3a978bf66d simplify some logic further 
llvm-svn: 23408
 2005-09-23 07:23:18 +00:00
Chris Lattner cc14ebc17b pull a bunch of logic out of SimplifyCFG into a helper fn 
llvm-svn: 23407
 2005-09-23 06:39:30 +00:00
Chris Lattner 6c70106053 Start threading across blocks with code in them, so long as the code does 
not define a value that is used outside of it's block.  This catches many
more simplifications, e.g. 854 in 176.gcc, 137 in vpr, etc.

This implements branch-phi-thread.ll:test3.ll

llvm-svn: 23397
 2005-09-20 01:48:40 +00:00
Chris Lattner f0bd8d0107 Implement merging of blocks with the same condition if the block has multiple 
predecessors.  This implements branch-phi-thread.ll::test1

llvm-svn: 23395
 2005-09-20 00:43:16 +00:00
Chris Lattner 049cb4482f Reject a case we don't handle yet 
llvm-svn: 23393
 2005-09-19 23:57:04 +00:00
Chris Lattner a160924d57 remove debugging code :-/ 
llvm-svn: 23392
 2005-09-19 23:50:15 +00:00
Chris Lattner 748f903046 Implement SimplifyCFG/branch-phi-thread.ll, the most trivial case of threading 
control across branches with determined outcomes.  More generality to follow.
This triggers a couple thousand times in specint.

llvm-svn: 23391
 2005-09-19 23:49:37 +00:00
Chris Lattner d683bdd0f8 Fix Transforms/SimplifyCFG/2005-08-03-PHIFactorCrash.ll, a problem that 
occurred while bugpointing another testcase

llvm-svn: 22621
 2005-08-03 17:59:45 +00:00
Chris Lattner 2dbf1960ff Finally, add the required constraint checks to fix Transforms/SimplifyCFG/2005-08-01-PHIUpdateFail.ll 
the right way

llvm-svn: 22615
 2005-08-03 00:59:12 +00:00
Chris Lattner 908036942c Simplify some code, add the correct pred checks 
llvm-svn: 22613
 2005-08-03 00:38:27 +00:00
Chris Lattner 982b75c061 Refactor code out of PropagatePredecessorsForPHIs, turning it into a pure function with no side-effects 
llvm-svn: 22612
 2005-08-03 00:29:26 +00:00
Chris Lattner 1f047fd513 use splice instead of remove/insert to avoid some symtab operations 
llvm-svn: 22611
 2005-08-03 00:23:42 +00:00
Chris Lattner 76dc204488 move two functions up in the file, use SafeToMergeTerminators to eliminate 
some duplicated code

llvm-svn: 22610
 2005-08-03 00:19:45 +00:00
Chris Lattner 733d6704ce Rip some code out of the main SimplifyCFG function into a subfunction and 
call it from the only place it is live.  No functionality changes.

llvm-svn: 22609
 2005-08-03 00:11:16 +00:00
Chris Lattner ac594de8dc Disable this patch: 
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20050801/027345.html

This breaks real programs and only fixes an obscure regression testcase.  A
real fix is in development.

llvm-svn: 22606
 2005-08-02 23:31:38 +00:00
Chris Lattner eee90f7eb4 Change a place to use an arbitrary value instead of null, when possible 
llvm-svn: 22605
 2005-08-02 23:29:23 +00:00
Chris Lattner 4fd3e16cbd This code was very close, but not quite right. It did not take into 
consideration the case where a reference in an unreachable block could
occur.  This fixes Transforms/SimplifyCFG/2005-08-01-PHIUpdateFail.ll,
something I ran into while bugpoint'ing another pass.

llvm-svn: 22584
 2005-08-02 03:24:05 +00:00
Chris Lattner 5e735294bf Don't crash on: X = phi (X, X). 
This fixes PR584 and Transforms/SimplifyCFG/2005-06-16-PHICrash.ll

llvm-svn: 22232
 2005-06-17 01:45:53 +00:00
Chris Lattner 19f9f32a5c Fix Transforms/SimplifyCFG/switch-simplify-crash.ll 
llvm-svn: 22158
 2005-05-20 22:19:54 +00:00
Chris Lattner bcefcf8552 Make sure to preserve the calling convention when changing an invoke into 
a call.  This fixes Prolangs-C++/deriv2, kimwitu++, and Misc-C++/bigfib
on X86 with -enable-x86-fastcc.

llvm-svn: 22023
 2005-05-14 12:21:56 +00:00
Misha Brukman b1c9317bb4 Remove trailing whitespace 
llvm-svn: 21427
 2005-04-21 23:48:37 +00:00
Chris Lattner b38b443b15 Teach simplifycfg that setcc is cheap and non-trapping, so that it can 
convert this:

        %tmp.1 = seteq int %i, 0                ; <bool> [#uses=1]
        br bool %tmp.1, label %shortcirc_done, label %shortcirc_next

shortcirc_next:         ; preds = %entry
        %tmp.4 = seteq int %j, 0                ; <bool> [#uses=1]
        br label %shortcirc_done

shortcirc_done:         ; preds = %shortcirc_next, %entry
        %shortcirc_val = phi bool [ %tmp.4, %shortcirc_next ], [ true, %entry ]         ; <bool> [#uses=1]

to this:
        %tmp.1 = seteq int %i, 0                ; <bool> [#uses=1]
        %tmp.4 = seteq int %j, 0                ; <bool> [#uses=1]
        %shortcirc_val = select bool %tmp.1, bool true, bool %tmp.4             ; <bool> [#uses=1]

... which is later simplified by instcombine into an or.

llvm-svn: 21388
 2005-04-21 05:31:13 +00:00
Chris Lattner 95f16a3ac4 Get rid of this for_each loop 
llvm-svn: 21253
 2005-04-12 18:51:33 +00:00
Chris Lattner 0ce80cd542 Fix spelling, patch contributed by Gabor Greif! 
llvm-svn: 20343
 2005-02-27 06:18:25 +00:00
Chris Lattner cc6d75fddf remove extraneous cast 
llvm-svn: 20334
 2005-02-26 18:33:28 +00:00
Chris Lattner 1cca959e5d Implement Transforms/SimplifyCFG/switch_thread.ll 
This does a simple form of "jump threading", which eliminates CFG edges that
are provably dead.  This triggers 90 times in the external tests, and
eliminating CFG edges is always always a good thing! :)

llvm-svn: 20300
 2005-02-24 06:17:52 +00:00
Chris Lattner a35dfcedd3 switchinst ctor now takes a hint for the number of cases that it will have. 
llvm-svn: 19898
 2005-01-29 00:38:26 +00:00
Chris Lattner 3215bb6049 Implement SimplifyCFG/DeadSetCC.ll 
SimplifyCFG is one of those passes that we use for final cleanup: it should
not rely on other passes to clean up its garbage.  This fixes the "why are
trivially dead setcc's in the output of gccas" problem.

llvm-svn: 19212
 2005-01-01 16:02:12 +00:00
Chris Lattner 4fc998da2e Fix Regression/Transforms/SimplifyCFG/2004-12-10-SimplifyCFGCrash.ll, 
and the failure on make_dparser last night.

llvm-svn: 18766
 2004-12-10 17:42:31 +00:00
Chris Lattner 019445715e Squelch warning 
llvm-svn: 18381
 2004-11-30 07:47:34 +00:00
Chris Lattner fd8cbc257e Alkis noticed that this variable is dead. Thanks! 
llvm-svn: 18369
 2004-11-30 04:01:44 +00:00
Chris Lattner 389cfac0d1 If we have something like this: 
if (x) {
    code
    ...
  } else {
    code
    ...
  }

Turn it into:

  code
  if (x) {
    ...
  } else {
    ...
  }

This reduces code size and in some common cases allows us to completely
eliminate the conditional.  This turns several if/then/else blocks in loops
into straightline code in 179.art, turning the loops into single basic blocks
(good for modsched even!).

Maybe now brg will leave me alone ;-)

llvm-svn: 18366
 2004-11-30 00:29:14 +00:00
Chris Lattner 93d1e39f3e Do not compute the predecessor list for a block unless we need it. 
This speeds up simplifycfg on this program, from 44.87s to 0.29s (with
a profiled build):

 #define CL0(a) case a: goto c;
 #define CL1(a) CL0(a##0) CL0(a##1) CL0(a##2) CL0(a##3) CL0(a##4) CL0(a##5) \
 CL0(a##6) CL0(a##7) CL0(a##8) CL0(a##9)
 #define CL2(a) CL1(a##0) CL1(a##1) CL1(a##2) CL1(a##3) CL1(a##4) CL1(a##5) \
 CL1(a##6) CL1(a##7) CL1(a##8) CL1(a##9)
 #define CL3(a) CL2(a##0) CL2(a##1) CL2(a##2) CL2(a##3) CL2(a##4) CL2(a##5) \
 CL2(a##6) CL2(a##7) CL2(a##8) CL2(a##9)
 #define CL4(a) CL3(a##0) CL3(a##1) CL3(a##2) CL3(a##3) CL3(a##4) CL3(a##5) \
 CL3(a##6) CL3(a##7) CL3(a##8) CL3(a##9)

 void f();

 void a() {
     int b;
  c: switch (b) {
         CL4(1)
     }
 }

This testcase is contrived to expose N^2 behavior, but this patch should speedup
simplifycfg on any programs that use large switch statements.  This testcase
comes from GCC PR17895.

llvm-svn: 17389
 2004-11-01 06:53:58 +00:00
Reid Spencer fad217c847 Eliminate compilation warning on uninitialized variable. 
llvm-svn: 17163
 2004-10-22 16:10:39 +00:00
Chris Lattner 5edb2f32d0 Simplify code by deleting instructions that preceed unreachable instructions. 
Simplify code by simplifying terminators that branch to blocks that start
with an unreachable instruction.

llvm-svn: 17116
 2004-10-18 04:07:22 +00:00
Chris Lattner 45c35b1d1f When converting phi nodes into select instructions, we shouldn't promote PHI 
nodes unless we KNOW that we are able to promote all of them.

This fixes: test/Regression/Transforms/SimplifyCFG/PhiNoEliminate.ll

llvm-svn: 16973
 2004-10-14 05:13:36 +00:00
Chris Lattner 879ce7894c Do not insert trivially dead select instructions, which allows us to 
potentially fold more in one pass.

llvm-svn: 16583
 2004-09-29 05:43:32 +00:00
Reid Spencer 6614946443 Convert code to compile with vc7.1. 
Patch contributed by Paolo Invernizzi. Thanks Paolo!

llvm-svn: 16368
 2004-09-15 17:06:42 +00:00
Alkis Evlogimenos a5c04ee50f Fixes to make LLVM compile with vc7.1. 
Patch contributed by Paolo Invernizzi!

llvm-svn: 16152
 2004-09-03 18:19:51 +00:00
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
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 5823ac1c21 Implement SimplifyCFG/BrUnwind.ll 
llvm-svn: 15022
 2004-07-20 01:17:38 +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
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 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 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
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
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 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 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 a078f47b39 Fix compilation of mesa, which I broke earlier today 
llvm-svn: 12465
 2004-03-17 02:02:47 +00:00
Chris Lattner a64923ad26 Do not copy gigantic switch instructions 
llvm-svn: 12441
 2004-03-16 19:45:22 +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
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 e42732e75f Implement test/Regression/Transforms/SimplifyCFG/UncondBranchToReturn.ll, 
see the testcase for the reasoning.

llvm-svn: 11496
 2004-02-16 06:35:48 +00:00
Chris Lattner 18d1f19fba Implement SimplifyCFG/PhiEliminate.ll 
Having a proper 'select' instruction would allow the elimination of a lot
of the special case cruft in this patch, but we don't have one yet.

llvm-svn: 11307
 2004-02-11 03:36:04 +00:00
Chris Lattner 838b845781 The hasConstantReferences predicate always returns false. 
llvm-svn: 11301
 2004-02-11 01:17:07 +00:00
Chris Lattner fae8ab3088 rename the "exceptional" destination of an invoke instruction to the 'unwind' dest 
llvm-svn: 11202
 2004-02-08 21:44:31 +00:00
Chris Lattner df3c342a4c Finegrainify namespacification 
llvm-svn: 10727
 2004-01-09 06:12:26 +00:00
Brian Gaeke 960707c335 Put all LLVM code into the llvm namespace, as per bug 109. 
llvm-svn: 9903
 2003-11-11 22:41:34 +00:00
John Criswell 482202a601 Added LLVM project notice to the top of every C++ source file. 
Header files will be on the way.

llvm-svn: 9298
 2003-10-20 19:43:21 +00:00
Misha Brukman 8b2bd4ed47 Fix spelling. 
llvm-svn: 9027
 2003-10-10 17:57:28 +00:00
Chris Lattner 04ecefe232 Eliminate support for the llvm.unwind intrinisic, using the Unwind instruction instead 
llvm-svn: 8411
 2003-09-08 19:44:26 +00:00
Chris Lattner 3f5823f131 Implement SimplifyCFG/InvokeEliminate.ll 
llvm-svn: 8126
 2003-08-24 18:36:16 +00:00