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------------------------------------------------------------------------ r293345 | spatel | 2017-01-27 15:26:27 -0800 (Fri, 27 Jan 2017) | 19 lines [InstCombine] move icmp transforms that might be recognized as min/max and inf-loop (PR31751) This is a minimal patch to avoid the infinite loop in: https://llvm.org/bugs/show_bug.cgi?id=31751 But the general problem is bigger: we're not canonicalizing all of the min/max forms reported by value tracking's matchSelectPattern(), and we don't define min/max consistently. Some code uses matchSelectPattern(), other code uses matchers like m_Umax, and others have their own inline definitions which may be subtly different from any of the above. The reason that the test cases in this patch need a cast op to trigger is because we don't (yet) canonicalize all min/max forms based on matchSelectPattern() in canonicalizeMinMaxWithConstant(), but we do make min/max+cast transforms based on matchSelectPattern() in visitSelectInst(). The location of the icmp transforms that trigger the inf-loop seems arbitrary at best, so I'm moving those behind the min/max fence in visitICmpInst() as the quick fix. ------------------------------------------------------------------------ git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_40@293947 91177308-0d34-0410-b5e6-96231b3b80d8