Change the other half of aliasGEP (which handles GEP differencing) to use DecomposeGEPExpression.  This dramatically simplifies and shrinks the code by eliminating the horrible CheckGEPInstructions method, fixes a miscompilation (@test3) and makes the code more aggressive.  In particular, we now handle the @test4 case, which is reduced from the SmallPtrSet constructor.  Missing this caused us to emit a variable length memset instead of a fixed size one.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89922 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed