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Commit Graph

41 Commits

Author SHA1 Message Date
Chris Lattner
d8345001fa Do not clone arbitrary condition instructions.
llvm-svn: 13316
2004-05-02 05:19:36 +00:00
Chris Lattner
da2d746a3b Do not infinitely "unroll" single BB loops.
llvm-svn: 13315
2004-05-02 05:02:03 +00:00
Chris Lattner
5f393764c8 Dont' merge terminators that are needed to select PHI node values.
llvm-svn: 13312
2004-05-02 01:00:44 +00:00
Chris Lattner
bd705d7776 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
911e21e8ca Fix my missing parens
llvm-svn: 13307
2004-05-01 22:41:51 +00:00
Chris Lattner
82278b599b Implement SimplifyCFG/branch-cond-prop.ll
llvm-svn: 13306
2004-05-01 22:36:37 +00:00
Chris Lattner
8ccddbd123 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
3f202e3a54 Fix the obvious bug in my previous checkin
llvm-svn: 12618
2004-04-02 18:15:10 +00:00
Chris Lattner
bca948c99d 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
145aea5c4c 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
849234af99 Fix compilation of mesa, which I broke earlier today
llvm-svn: 12465
2004-03-17 02:02:47 +00:00
Chris Lattner
2175b35b46 Do not copy gigantic switch instructions
llvm-svn: 12441
2004-03-16 19:45:22 +00:00
Chris Lattner
a854ddd528 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
e07d786aa6 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
7845e4f7f0 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
d678669018 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
1293e1d00c Rearrange code a bit
llvm-svn: 11793
2004-02-24 05:54:22 +00:00
Chris Lattner
e5db7dc4c6 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
f51bbb7eec 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
4418633216 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
754914b142 The hasConstantReferences predicate always returns false.
llvm-svn: 11301
2004-02-11 01:17:07 +00:00
Chris Lattner
68fdb35576 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
031bd7e9f3 Finegrainify namespacification
llvm-svn: 10727
2004-01-09 06:12:26 +00:00
Brian Gaeke
d25f86d683 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
b402729b30 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
868eac95dd Fix spelling.
llvm-svn: 9027
2003-10-10 17:57:28 +00:00
Chris Lattner
e8ae7bf114 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
a0203709f4 Implement SimplifyCFG/InvokeEliminate.ll
llvm-svn: 8126
2003-08-24 18:36:16 +00:00
Chris Lattner
1f5afd2a1c Fix bug: SimplifyCFG/2003-08-17-BranchFoldOrdering.ll
llvm-svn: 7921
2003-08-17 19:41:53 +00:00
Chris Lattner
488b0e52a8 Fix bug: SimplifyCFG/2003-08-05-InvokeCrash.ll
Fix bug: SimplifyCFG/2003-08-05-MishandleInvoke.ll

llvm-svn: 7599
2003-08-05 16:27:44 +00:00
Chris Lattner
db6b7ba364 Remove unnecesary &*'s
llvm-svn: 5872
2003-04-23 16:37:45 +00:00
Chris Lattner
9f2f48a648 Fix bug: SimplifyCFG/2003-03-07-DominateProblem.ll
llvm-svn: 5722
2003-03-07 18:13:41 +00:00
Chris Lattner
4a9f0be9dd Implement CFGSimplify/PhiBlockMerge*.ll
llvm-svn: 5702
2003-03-05 21:36:33 +00:00
Chris Lattner
e025920ff8 Implement testcase CFGSimplify/EqualPHIEdgeBlockMerge.ll
llvm-svn: 5699
2003-03-05 21:01:52 +00:00
Misha Brukman
c9c721edf0 Fix spelling of `propagate'.
llvm-svn: 4423
2002-10-29 23:06:16 +00:00
Chris Lattner
9c236351fd Changes to support PHINode::removeIncoming changes
llvm-svn: 4079
2002-10-08 21:36:33 +00:00
Chris Lattner
54cf78c786 Fix bug: SimplifyCFG/2002-09-24-PHIAssertion.ll
llvm-svn: 3913
2002-09-24 16:09:17 +00:00
Chris Lattner
4e11d9e5de Minor cleanups
llvm-svn: 3904
2002-09-24 00:09:26 +00:00
Chris Lattner
2f7ce877c5 Allow folding of basic blocks that have PHI nodes in them, fixing "bug":
test/Regression/Transforms/SimplifyCFG/2002-06-24-PHINode.ll

llvm-svn: 3128
2002-07-29 21:26:30 +00:00
Chris Lattner
cee706572b *** empty log message ***
llvm-svn: 2777
2002-06-25 16:12:52 +00:00
Chris Lattner
e7ce749d63 Add implementation of SimplifyCFG
llvm-svn: 2701
2002-05-21 20:50:24 +00:00