Commit Graph

38 Commits

Author SHA1 Message Date
Chris Lattner
e67fa05036 Implement SimplifyCFG/branch-cond-merge.ll
Turning "if (A < B && B < C)" into "if (A < B & B < C)"


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13311 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-01 23:35:43 +00:00
Chris Lattner
951fdb9764 Fix my missing parens
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13307 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-01 22:41:51 +00:00
Chris Lattner
92da2c2053 Implement SimplifyCFG/branch-cond-prop.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13306 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-01 22:36:37 +00:00
Chris Lattner
570751c2a7 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) ;
}


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12798 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-09 22:50:22 +00:00
Chris Lattner
7aa773bc07 Fix the obvious bug in my previous checkin
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12618 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-02 18:15:10 +00:00
Chris Lattner
147af6b75f Implement Transforms/SimplifyCFG/return-merge.ll
This actually causes us to turn code like:

  return C ? A : B;

into a select instruction.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12617 91177308-0d34-0410-b5e6-96231b3b80d8
2004-04-02 18:13:43 +00:00
Chris Lattner
552112f2f8 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


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12545 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-30 19:44:05 +00:00
Chris Lattner
7acd1ccb8a Fix compilation of mesa, which I broke earlier today
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12465 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-17 02:02:47 +00:00
Chris Lattner
4bebf08d15 Do not copy gigantic switch instructions
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@12441 91177308-0d34-0410-b5e6-96231b3b80d8
2004-03-16 19:45:22 +00:00
Chris Lattner
542f149f00 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11964 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-28 21:28:10 +00:00
Chris Lattner
f2dbf50efa 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11870 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-26 07:13:46 +00:00
Chris Lattner
8e509dd5e8 If a block is made dead, make sure to promptly remove it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11799 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24 16:09:21 +00:00
Chris Lattner
d52c261cf8 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)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11797 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24 07:23:58 +00:00
Chris Lattner
e14ea0804a Rearrange code a bit
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11793 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24 05:54:22 +00:00
Chris Lattner
0d56008f53 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11792 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-24 05:38:11 +00:00
Chris Lattner
19831ec853 Implement test/Regression/Transforms/SimplifyCFG/UncondBranchToReturn.ll,
see the testcase for the reasoning.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11496 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-16 06:35:48 +00:00
Chris Lattner
723c66d4c0 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11307 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-11 03:36:04 +00:00
Chris Lattner
2355f948c5 The hasConstantReferences predicate always returns false.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11301 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-11 01:17:07 +00:00
Chris Lattner
aeb2a1d708 rename the "exceptional" destination of an invoke instruction to the 'unwind' dest
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@11202 91177308-0d34-0410-b5e6-96231b3b80d8
2004-02-08 21:44:31 +00:00
Chris Lattner
f7703df496 Finegrainify namespacification
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@10727 91177308-0d34-0410-b5e6-96231b3b80d8
2004-01-09 06:12:26 +00:00
Brian Gaeke
d0fde30ce8 Put all LLVM code into the llvm namespace, as per bug 109.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9903 91177308-0d34-0410-b5e6-96231b3b80d8
2003-11-11 22:41:34 +00:00
John Criswell
b576c94c15 Added LLVM project notice to the top of every C++ source file.
Header files will be on the way.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9298 91177308-0d34-0410-b5e6-96231b3b80d8
2003-10-20 19:43:21 +00:00
Misha Brukman
cf00c4ab3b Fix spelling.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9027 91177308-0d34-0410-b5e6-96231b3b80d8
2003-10-10 17:57:28 +00:00
Chris Lattner
ee5457cbe8 Eliminate support for the llvm.unwind intrinisic, using the Unwind instruction instead
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8411 91177308-0d34-0410-b5e6-96231b3b80d8
2003-09-08 19:44:26 +00:00
Chris Lattner
dc3602bf0d Implement SimplifyCFG/InvokeEliminate.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@8126 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-24 18:36:16 +00:00
Chris Lattner
694e37f08a Fix bug: SimplifyCFG/2003-08-17-BranchFoldOrdering.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7921 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-17 19:41:53 +00:00
Chris Lattner
122558b05b Fix bug: SimplifyCFG/2003-08-05-InvokeCrash.ll
Fix bug: SimplifyCFG/2003-08-05-MishandleInvoke.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@7599 91177308-0d34-0410-b5e6-96231b3b80d8
2003-08-05 16:27:44 +00:00
Chris Lattner
e408e25132 Remove unnecesary &*'s
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5872 91177308-0d34-0410-b5e6-96231b3b80d8
2003-04-23 16:37:45 +00:00
Chris Lattner
3a43837d85 Fix bug: SimplifyCFG/2003-03-07-DominateProblem.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5722 91177308-0d34-0410-b5e6-96231b3b80d8
2003-03-07 18:13:41 +00:00
Chris Lattner
46a5f1f6e4 Implement CFGSimplify/PhiBlockMerge*.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5702 91177308-0d34-0410-b5e6-96231b3b80d8
2003-03-05 21:36:33 +00:00
Chris Lattner
e2ca540e7c Implement testcase CFGSimplify/EqualPHIEdgeBlockMerge.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5699 91177308-0d34-0410-b5e6-96231b3b80d8
2003-03-05 21:01:52 +00:00
Misha Brukman
a3bbcb5b66 Fix spelling of `propagate'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4423 91177308-0d34-0410-b5e6-96231b3b80d8
2002-10-29 23:06:16 +00:00
Chris Lattner
bb190ac8da Changes to support PHINode::removeIncoming changes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4079 91177308-0d34-0410-b5e6-96231b3b80d8
2002-10-08 21:36:33 +00:00
Chris Lattner
929b2c6900 Fix bug: SimplifyCFG/2002-09-24-PHIAssertion.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3913 91177308-0d34-0410-b5e6-96231b3b80d8
2002-09-24 16:09:17 +00:00
Chris Lattner
3abb95df01 Minor cleanups
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3904 91177308-0d34-0410-b5e6-96231b3b80d8
2002-09-24 00:09:26 +00:00
Chris Lattner
91b65c0b42 Allow folding of basic blocks that have PHI nodes in them, fixing "bug":
test/Regression/Transforms/SimplifyCFG/2002-06-24-PHINode.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@3128 91177308-0d34-0410-b5e6-96231b3b80d8
2002-07-29 21:26:30 +00:00
Chris Lattner
18961504fc *** empty log message ***
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2777 91177308-0d34-0410-b5e6-96231b3b80d8
2002-06-25 16:12:52 +00:00
Chris Lattner
01d1ee3a4c Add implementation of SimplifyCFG
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2701 91177308-0d34-0410-b5e6-96231b3b80d8
2002-05-21 20:50:24 +00:00