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Louis Gerbarg 8d2a43e9be Add support for combining GEPs across PHI nodes

Currently LLVM will generally merge GEPs. This allows backends to use more
complex addressing modes. In some cases this is not happening because there
is PHI inbetween the two GEPs:

  GEP1--\
        |-->PHI1-->GEP3
  GEP2--/

This patch checks to see if GEP1 and GEP2 are similiar enough that they can be
cloned (GEP12) in GEP3's BB, allowing GEP->GEP merging (GEP123):

  GEP1--\                     --\                           --\
        |-->PHI1-->GEP3  ==>    |-->PHI2->GEP12->GEP3 == >    |-->PHI2->GEP123
  GEP2--/                     --/                           --/

This also breaks certain use chains that are preventing GEP->GEP merges that the
the existing instcombine would merge otherwise.

Tests included.

rdar://15547484

llvm-svn: 209049

2014-05-16 23:47:24 +00:00

Hello

[Modules] Fix potential ODR violations by sinking the DEBUG_TYPE

2014-04-22 02:55:47 +00:00

InstCombine

Add support for combining GEPs across PHI nodes

2014-05-16 23:47:24 +00:00

Instrumentation

Delete getAliasedGlobal.

2014-05-16 22:37:03 +00:00

IPO

Fix most of PR10367.