llvm-svn: 17110

occurs in the entry node of a function

llvm-svn: 17109

particular, invoke ret values are only live in the normal dest of the invoke
not in the unwind dest.

llvm-svn: 17108

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

If a function had no return instruction in it, and the result of the inlined
call instruction was used, we would crash.

llvm-svn: 17104

other blocks.

llvm-svn: 17099

unneccesary.  This allows us to delete several hundred phi nodes of the
form PHI(x,x,x,undef) from 253.perlbmk and probably other programs as well.

This implements Mem2Reg/UndefValuesMerge.ll

llvm-svn: 17098

to think that PHI[4, undef] == 4.

llvm-svn: 17096

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: 17056

llvm-svn: 17047

llvm-svn: 17046

llvm-svn: 17045

ignore unreachable instructions

llvm-svn: 17044

llvm-svn: 17043

that are initialized with undef.  When promoting malloc to a global, start out
initialized to undef

llvm-svn: 17042

weak functions.  Thanks for finding this John!

llvm-svn: 16997

nodes unless we KNOW that we are able to promote all of them.

This fixes: test/Regression/Transforms/SimplifyCFG/PhiNoEliminate.ll

llvm-svn: 16973

llvm-svn: 16950

llvm-svn: 16932

marker from one ilist into the middle of another basic block!

llvm-svn: 16925

pointer recurrences into expressions from this:

  %P_addr.0.i.0 = phi sbyte* [ getelementptr ([8 x sbyte]* %.str_1, int 0, int 0), %entry ], [ %inc.0.i, %no_exit.i ]
  %inc.0.i = getelementptr sbyte* %P_addr.0.i.0, int 1            ; <sbyte*> [#uses=2]

into this:

  %inc.0.i = getelementptr sbyte* getelementptr ([8 x sbyte]* %.str_1, int 0, int 0), int %inc.0.i.rec

Actually create something nice, like this:

  %inc.0.i = getelementptr [8 x sbyte]* %.str_1, int 0, int %inc.0.i.rec

llvm-svn: 16924

llvm-svn: 16918

First, it allows SRA of globals that have embedded arrays, implementing
GlobalOpt/globalsra-partial.llx.  This comes up infrequently, but does allow,
for example, deleting several stores to dead parts of globals in dhrystone.

Second, this implements GlobalOpt/malloc-promote-*.llx, which is the
following nifty transformation:

Basically if a global pointer is initialized with malloc, and we can tell
that the program won't notice, we transform this:

struct foo *FooPtr;
...
  FooPtr = malloc(sizeof(struct foo));
...
  FooPtr->A   FooPtr->B

Into:

struct foo FooPtrBody;
...
   FooPtrBody.A  FooPtrBody.B

This comes up occasionally, for example, the 'disp' global in 183.equake (where
the xform speeds the CBE version of the program up from 56.16s to 52.40s (7%)
on apoc), and the 'desired_accept', 'fixLRBT', 'macroArray', & 'key_queue'
globals in 300.twolf (speeding it up from 22.29s to 21.55s (3.4%)).

The nice thing about this xform is that it exposes the resulting global to
global variable optimization and makes alias analysis easier in addition to
eliminating a few loads.

llvm-svn: 16916

still optimize away all of the indirect calls and loads, etc from it.
This turns code like this:

  if (G != 0)
    G();

into
   if (G != 0)
     ActualCallee();

This triggers a couple of times in gcc and libstdc++.

llvm-svn: 16901

llvm-svn: 16893

llvm-svn: 16878

stored to, but are stored at variable indexes.  This occurs at least in
176.gcc, but probably others, and we should handle it for completeness.

llvm-svn: 16876

has a large number of users.  Instead, just keep track of whether we're
making changes as we do so.

This patch has no functionlity changes.

llvm-svn: 16874

we know that all uses of the global will trap if the pointer contained is
null.  In this case, we forward substitute the stored value to any uses.

This has the effect of devirtualizing trivial globals in trivial cases.  For
example, 164.gzip contains this:

gzip.h:extern   int (*read_buf) OF((char *buf, unsigned size));
bits.c: read_buf  = file_read;
deflate.c:    lookahead = read_buf((char*)window,
deflate.c:        n = read_buf((char*)window+strstart+lookahead, more);

Since read_buf has to point to file_read at every use, we just replace
the calls through read_buf with a direct call to file_read.

This occurs in several benchmarks, including 176.gcc and 164.gzip.  Direct
calls are good and stuff.

llvm-svn: 16871

-debug-only!

llvm-svn: 16868

llvm-svn: 16864

llvm-svn: 16863

llvm-svn: 16858

* Do not lead dangling dead constants prevent optimization
* Iterate global optimization while we're making progress.

These changes allow us to be more aggressive, handling cases like
GlobalOpt/iterate.llx without a problem (turning it into 'ret int 0').

llvm-svn: 16857

we know it is dead.

llvm-svn: 16855

254.gap.

llvm-svn: 16853