llvm-svn: 17818

class.  The only changes are minor:

 * Do not try to SCCP instructions that return void in the rewrite loop.
   This is silly and fool hardy, wasting a map lookup and adding an entry
   to the map which is never used.
 * If we decide something has an undefined value, rewrite it to undef,
   potentially leading to further simplications.

llvm-svn: 17816

If this happens, detect it early instead of relying on instcombine to notice
it later.  This can be a big speedup, because PHI nodes can have many
incoming values.

llvm-svn: 17741

This exposes subsequent optimization possiblities and reduces code size.
This triggers 1423 times in spec.

llvm-svn: 17740

  %X = alloca ...
  %Y = alloca ...
    X == Y

into false.  This allows us to simplify some stuff in eon (and probably
many other C++ programs) where operator= was checking for self assignment.
Folding this allows us to SROA several additional structs.

llvm-svn: 17735

of the array is just two.  This occurs 8 times in gcc, 6 times in crafty, and
12 times in 099.go.

This implements ScalarRepl/sroa_two.ll

llvm-svn: 17727

llvm-svn: 17724

for (X * C1) + (X * C2) (where * can be mul or shl), allowing us to fold:

   Y+Y+Y+Y+Y+Y+Y+Y

into
         %tmp.8 = shl long %Y, ubyte 3           ; <long> [#uses=1]

instead of

        %tmp.4 = shl long %Y, ubyte 2           ; <long> [#uses=1]
        %tmp.12 = shl long %Y, ubyte 2          ; <long> [#uses=1]
        %tmp.8 = add long %tmp.4, %tmp.12               ; <long> [#uses=1]

This implements add.ll:test25

Also add support for (X*C1)-(X*C2) -> X*(C1-C2), implementing sub.ll:test18

llvm-svn: 17704

   (X + (X << C2)) --> X * ((1 << C2) + 1)
   ((X << C2) + X) --> X * ((1 << C2) + 1)

This means that we now canonicalize "Y+Y+Y" into:

        %tmp.2 = mul long %Y, 3         ; <long> [#uses=1]

instead of:

        %tmp.10 = shl long %Y, ubyte 1          ; <long> [#uses=1]
        %tmp.6 = add long %Y, %tmp.10               ; <long> [#uses=1]

llvm-svn: 17701

will actually get it.

llvm-svn: 17700

llvm-svn: 17696

llvm-svn: 17545

llvm-svn: 17481

* Disable broken transforms for simplifying (setcc (cast X to larger), CI)
  where CC is not != or ==

llvm-svn: 17422

#define CL0(a) case a: f(); 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 comes from GCC PR 15524

llvm-svn: 17390

llvm-svn: 17286

and work better with VC++.  Patch contributed by Morten Ofstad!

llvm-svn: 17281

http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20041018/019708.html

exposed ANOTHER latent bug in this xform, which caused Prolangs-C/bison to fill
the zion nightly tester disk up and make the tester barf.

This is obviously not a good thing, so lets fix this bug shall we? :)

llvm-svn: 17276

llvm-svn: 17270

llvm-svn: 17218

llvm-svn: 17157

llvm-svn: 17155

doing... I guess they're right.

llvm-svn: 17142

llvm-svn: 17136

loops.  This optimization is not turned on by default yet, but may be run
with the opt tool's -loop-reduce flag.  There are many FIXMEs listed in the
code that will make it far more applicable to a wide range of code, but you
have to start somewhere :)

This limited version currently triggers on the following tests in the
MultiSource directory:
pcompress2: 7 times
cfrac: 5 times
anagram: 2 times
ks: 6 times
yacr2: 2 times

llvm-svn: 17134

Patch contributed by Morten Ofstad. Thanks Morten!

llvm-svn: 17123

change hacks off 10K of bytecode from perlbmk (.5%) even though the front-end
is not generating them yet and we are not optimizing the resultant code.
This isn't too bad.

llvm-svn: 17111

llvm-svn: 17110

occurs in the entry node of a function

llvm-svn: 17109

exercise that I'm not interested in tackling right now.  Just punt and treat them
like unwind's.

This 'fixes' test/Regression/Transforms/ADCE/unreachable-function.ll

llvm-svn: 17106

other blocks.

llvm-svn: 17099

so prepare for this.

llvm-svn: 17095

llvm-svn: 17069

llvm-svn: 17067

ugly and giant constnat exprs in some programs.

llvm-svn: 17066

llvm-svn: 17047

ignore unreachable instructions

llvm-svn: 17044

llvm-svn: 17043

llvm-svn: 16950

llvm-svn: 16932