load elimination code from RedundantLoadElimination.

llvm-svn: 40469

llvm-svn: 40457

llvm-svn: 40456

llvm-svn: 40448

llvm-svn: 40445

llvm-svn: 40440

undefs.

llvm-svn: 40439

reported in PR 1556.

llvm-svn: 40133

llvm-svn: 40124

llvm-svn: 40102

pacifies g++-4.2.

llvm-svn: 40089

llvm-svn: 40085

llvm-svn: 40064

With this, the time to optimize 403.gcc is down to 15.1s.

llvm-svn: 40042

This results in a slight speedup for 403.gcc.

llvm-svn: 40040

reduces the time to optimize 403.gcc from 17.6s to 16.4s.

llvm-svn: 40036

llvm-svn: 40025

This fixes PR1559.

llvm-svn: 40024

beyond the end of an alloca to make FastDSE faster and more aggressive.

llvm-svn: 39945

dead stores on 400.perlbench.

llvm-svn: 39929

llvm-svn: 39921

llvm-svn: 39896

llvm-svn: 39894

First teach instcombine that sign bit checks only demand the 
sign bit, this allows simplify demanded bits to hack on 
expressions better.

Second, teach instcombine that ashr is useless if only the
sign bit is demanded.

llvm-svn: 39880

(X << 31) <s 0  --> (X&1) != 0

This happens dozens of times in the CFE.

llvm-svn: 39879

llvm-svn: 39852

Handle GEPs with all-zero indices in the same way we handle pointer-pointer bitcasts. Also, fix a potentia infinite loop.

This brings FastDSE to parity with old DSE on 175.vpr.

llvm-svn: 39839

llvm-svn: 39834

This drastically improves the effect of FastDSE on kimwitu++.

llvm-svn: 39819

llvm-svn: 39790

llvm-svn: 39789

Remove the end-block handling code.  It was unsafe, and making it safe would have resulted in falling back to the slow DSE case.  I need to think some more about the right way to handle this.

llvm-svn: 39788

thanks Benoit Boissinot!

llvm-svn: 39774

llvm-svn: 39769

llvm-svn: 39767

that structure.

Also, refactor the runOnBasicBlock() function, splitting some of the special cases into separate functions.

llvm-svn: 39762

of a function.

llvm-svn: 39754

llvm-svn: 39753

llvm-svn: 39747

as the current DSE, but it only a linear scan over each block, rather than quadratic.  Eventually
(once it has been improved somewhat), this will replace the current DSE.

NOTE: This has not yet been extensively tested.
llvm-svn: 38517