forked from OSchip/llvm-project
0bdc027e31
Summary: Converting outermost zext(a) to sext(a) causes worse code when the computation of zext(a) could be reused. For example, after converting ... = array[zext(a)] ... = array[zext(a) + 1] to ... = array[sext(a)] ... = array[zext(a) + 1], the program computes sext(a), which is actually unnecessary. I added one test in split-gep-and-gvn.ll to illustrate this scenario. Also, with r211281 and r211084, we annotate more "nuw" tags to computation involving CUDA intrinsics such as threadIdx.x. These annotations help with splitting GEP a lot, rendering the benefit we get from this reverted optimization only marginal. Test Plan: make check-all Reviewers: eliben, meheff Reviewed By: meheff Subscribers: jholewinski, llvm-commits Differential Revision: http://reviews.llvm.org/D4542 llvm-svn: 213209 |
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lit.local.cfg | ||
split-gep-and-gvn.ll | ||
split-gep.ll |