[PATCH] D31194: [InstSimplify] Try to Constant Fold the Instruction before simplification

Daniel Berlin via Phabricator via llvm-commits llvm-commits at lists.llvm.org
Thu Jun 1 09:24:52 PDT 2017


dberlin added inline comments.


================
Comment at: test/Transforms/NewGVN/completeness.ll:403
 ; CHECK:       k:
-; CHECK-NEXT:    br i1 false, label [[C]], label [[O:%.*]]
+; CHECK-NEXT:    br i1 %{{.*}}, label [[C]], label [[O:%.*]]
 ; CHECK:       o:
----------------
dberlin wrote:
> Did you change this manually?
> We normally use update_test_checks on these tests, and i've never seen it do that.
> (also, the update would mean we lost optimization, since it should stay false)
Just tested it.
It's definitely lost optimization.
We are not longer able to simplify that br i1 to false, because we don't simplify the phi to false with this patch,.



https://reviews.llvm.org/D31194





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