R600: Use lower-case for EnableIRStructurizer feature

llc converts all values passed to -mattr= to lowercase, so this
enables us to toggle this feature when using llc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195028 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Add a SubtargetFeatture for disabling the ifcvt pass.

This is useful when writing test cases for the AMDIL structurizer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195029 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Fix a crash in the AMDILCFGStrucurizer

The ifPatternMatch() function was not correctly reporting the number
of matches in some cases.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195030 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Enable the IR structurizer by default

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@195031 91177308-0d34-0410-b5e6-96231b3b80d8