Commit Graph

2 Commits

Author SHA1 Message Date
Chris Lattner
39c27eddc5 Fix PR3452 (an infinite loop bootstrapping) by disabling the recent
improvements to the EvaluateInDifferentType code.  This code works 
by just inserted a bunch of new code and then seeing if it is 
useful.  Instcombine is not allowed to do this: it can only insert
new code if it is useful, and only when it is converging to a more
canonical fixed point.  Now that we iterate when DCE makes progress,
this causes an infinite loop when the code ends up not being used.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63483 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-31 19:05:27 +00:00
Evan Cheng
f35fd547ac - Teach CanEvaluateInDifferentType of this xform: sext (zext ty1), ty2 -> zext ty2
- Looking at the number of sign bits of the a sext instruction to determine  whether new trunc + sext pair should be added when its source is being evaluated in a different type.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62263 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-15 17:01:23 +00:00