Commit Graph

542 Commits

Author SHA1 Message Date
1654cff8e8 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.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14243 91177308-0d34-0410-b5e6-96231b3b80d8
2004-06-19 07:02:14 +00:00
bdcc0b8c55 Do not clone arbitrary condition instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13316 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-02 05:19:36 +00:00
12fe2b1b82 Do not infinitely "unroll" single BB loops.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13315 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-02 05:02:03 +00:00
a1f79fb08b Dont' merge terminators that are needed to select PHI node values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@13312 91177308-0d34-0410-b5e6-96231b3b80d8
2004-05-02 01:00:44 +00:00
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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