[LLVMbugs] [Bug 8866] instcombine does not get max if hidden by sext

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=8866

Tobias Grosser <grosser at fim.uni-passau.de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #4 from Tobias Grosser <grosser at fim.uni-passau.de> 2011-01-07 15:55:03 CST ---
(In reply to comment #3)
> Patch posted:
> http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20110103/114606.html
> 
> Thanks Dan for the hint

An improved version of this patch committed:

Revision: 123034
URL: http://llvm.org/viewvc/llvm-project?rev=123034&view=rev
Log: InstCombine: Match min/max hidden by sext/zext

X = sext x; x >s c ? X : C+1 --> X = sext x; X <s C+1 ? C+1 : X
X = sext x; x <s c ? X : C-1 --> X = sext x; X >s C-1 ? C-1 : X
X = zext x; x >u c ? X : C+1 --> X = zext x; X <u C+1 ? C+1 : X
X = zext x; x <u c ? X : C-1 --> X = zext x; X >u C-1 ? C-1 : X
X = sext x; x >u c ? X : C+1 --> X = sext x; X <u C+1 ? C+1 : X
X = sext x; x <u c ? X : C-1 --> X = sext x; X >u C-1 ? C-1 : X

Instead of calculating this with mixed types promote all to the
larger type. This enables scalar evolution to analyze this
expression. PR8866

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