several ways:
* Load expressions are not PRE'd well. Alias Analysis should be used to
get accurate information when computing anticipatibility.
* The expression collection implementation does not handle PHI nodes properly,
thus the implementation misses many opportunities to PRE.
* This code could be sped up quite a bit
Despite these flaws, the code seems to work well, and handles PR's as one
would expect.
llvm-svn: 5759
- Null values are implicitly encoded instead of explicitly, this makes
things more compact!
- More compactly represent ConstantPointerRefs
- Bytecode files are represented as:
Header|GlobalTypes|GlobalVars/Function Protos|Constants|Functions|SymTab
instead of
Header|GlobalTypes|Constants|GlobalVars/Function Protos|Functions|SymTab
which makes a lot of things simpler.
Writer changes:
- We now explictly encode versioning information in the bytecode files.
- This allows new code to read bytecode files produced by old code, but
new bytecode files can have enhancements such as the above. Although this
makes the reader a bit more complex (having to deal with old formats), the
writer only needs to be able to produce the most recent version.
llvm-svn: 5749
- Fix problems where the constant table would not get updated when
resolving constants causes other constants to change.
Changes to the V2 bytecode format
- Null values are implicitly encoded instead of explicitly, this makes
things more compact!
- More compactly represent ConstantPointerRefs
- Bytecode files are represented as:
Header|GlobalTypes|GlobalVars/Function Protos|Constants|Functions|SymTab
instead of
Header|GlobalTypes|Constants|GlobalVars/Function Protos|Functions|SymTab
which makes a lot of things simpler.
Changes to the reader:
- Function loading code is much simpler. We now no longer make function
PlaceHolderHelper objects to be replaced with real functions.
llvm-svn: 5748
allows optimization of this:
int %test4(int %A, int %B) {
%a = xor int %A, -1
%c = and int %a, 5 ; 5 = ~c2
%d = xor int %c, -1
ret int %d
}
into this:
int %test4(int %A, int %B) { ; No predecessors!
%c.demorgan = or int %A, -6 ; <int> [#uses=1]
ret int %c.demorgan
}
llvm-svn: 5736
Chris Lattner