[PATCH] D39262: [CodeGen] Peel off the dominant case in switch statement in lowering

[Hans Wennborg via Phabricator via llvm-commits]

hans added inline comments.


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Comment at: test/CodeGen/Generic/switch-lower-peel-top-case.ll:72
+; CHECK:   %{{[0-9]+}}:gr32 = ADD32ri8 %{{[0-9]+}}, -85, implicit-def dead %eflags
+; CHECK:   %{{[0-9]+}}:gr32 = SUB32ri8 %{{[0-9]+}}, 2, implicit-def %eflags
+; CHECK:   JB_1 %[[RETURN_LABEL]], implicit %eflags
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Actually, I think this test would pass even without switch peeling.
Since there are only three clusters, it will do straight-line comparisons, with the most probable one (i.e. 85-86) first.
I'd suggest adding a few more cases, so that the remaining cases are lowered with a binary tree. That will show more clearly that the switch is getting peeled.


https://reviews.llvm.org/D39262