[llvm-bugs] [Bug 52518] New: [InstCombine] Failure to simplify (~A|B)^A --> ~(A&B)

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=52518

            Bug ID: 52518
           Summary: [InstCombine] Failure to simplify (~A|B)^A --> ~(A&B)
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
          Assignee: unassignedbugs at nondot.org
          Reporter: jay.foad at gmail.com
                CC: llvm-bugs at lists.llvm.org

InstCombine should simplify (~A|B)^A --> ~(A&B).

Here's CompilerExplorer showing that (a) the transformation is valid according
to Alive2, and (b) "opt -O2" does not do it:
https://alive2.llvm.org/ce/#z:OYLghAFBqd5QCxAYwPYBMCmBRdBLAF1QCcAaPECAM1QDsCBlZAQwBtMQBGAFlICsupVs1qhWrAG4BbUgGdM7ZATx1KmWugDCqVgFcptLgFZS69ABk8tTADl9AI0zEQAdlIAHVLMIra2vQbGHl4%2BdJbWdlKOzm7yisp0DATMxAT%2B%2BoacJnGYSr5JKQThtg5OrnLJqemBWRWFxZHRrgCUcqi6xMgcAORYVFaYANR43IMAAgTABBAjgwCkAExGAAykw6OLRpzNg6yoLKwA%2Brq0tMxSmOiHzOjoxPMLAMzL8y4AQnPLAIL29iCfX0GDyMC3mjwAIoMROh1sDOGtNssAUDNo8wZCAB4kWGbBZrAC0nGRg2ImAIOKWjwBcxc4IBfQGsLGsk6Mw2S1WFK2Oz2B2Op3Ol2ut3ui2erw%2B31%2B/2%2BKKWoLmEMGWPus0RBKJsuBaMVkOxavlCKWmsBwI2SpVXMeRpWxNJ5INRm41NpAO6rVYIG6Rm6pEM3WWvtQXvM5gAagBZQYASQASoNZO1OkMxZxfQQvYHmq0ANYgFZCL3cX3%2BwOkYPdX2yECrDMB92kOCwGCIFCoKTuPDsMgUCBoDtdsqodwEUj9VgEJzViB/eukexWFIATy9adI/Yu9AA8rRWCu51gpCJgOxM778KS8hJMNW55gMbldJPV76rJPPXPWHh7MRl9osC%2BpAEMQeBSC%2BrQ0PQTBsBwPD8IIwiiCA4jSEI37VpArTDgktC3viW4LFWCi5DhagaNUmSmBoDSlM48KeN4OEUYIDGhLQNFRGU8I5HkiSVGkOgZIIPE4QUqQcU03H8cxUn1AMjRca0iYdF0XAel6Pp%2Bme5ZethgwQLghDYqmazaAO3YPI82yDKGkYxrG6ZntmpAIJgNxlBAub5qsH7FqQYEFqWQZelWNZAU5jYthASD9p23bkJQsWDs4bB4NeY5dpOxDTrOZYLmcxD7muG7qAQO57tph7HqeB54JeyjXreZb3o%2Bz7dGub4KNpX4/n%2BGA9GuwGgeBY50IwBywbwAh4ohYiSDIPUYZ55Yjr4t5EfEvhkVogk1FRFjybRLEhExu2UaxOESVxcjEbxtBiQJASUSJ%2BT8VddF1FUZ3CW9h2cXRSlJqp2yFt6JbaRWqXXviBASPphlEKKTzwoMZlxU4lkLDstlRnGjn1s5rnuc4y2%2Bb6AWrEFOmVnIYV1lmXkFh%2Bjzg3OFb4wzoOEVpbMheFBOtNe2VbdwQA%3D%3D%3D

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