Commit Graph

72 Commits

Author SHA1 Message Date
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