Teach SCEV to handle more cases of 'and X, CST', specifically where CST is any number of contiguous 1 bits in a row, with any number of leading and trailing 0 bits.
Unfortunately, this in turn led to some lower quality SCEVs due to some different paths through expression simplification, so add getUDivExactExpr and use it. This fixes all instances of the problems that I found, but we can make that function smarter as necessary.
Merge test "xor-and.ll" into "and-xor.ll" since I needed to update it anyways. Test 'nsw-offset.ll' analyzes a little deeper, %n now gets a scev in terms of %no instead of a SCEVUnknown.
llvm-svn: 200203
diff --git a/llvm/test/Analysis/ScalarEvolution/nsw-offset.ll b/llvm/test/Analysis/ScalarEvolution/nsw-offset.ll
index 8969a5a..88cdcf2 100644
--- a/llvm/test/Analysis/ScalarEvolution/nsw-offset.ll
+++ b/llvm/test/Analysis/ScalarEvolution/nsw-offset.ll
@@ -73,5 +73,5 @@
ret void
}
-; CHECK: Loop %bb: backedge-taken count is ((-1 + %n) /u 2)
+; CHECK: Loop %bb: backedge-taken count is ((-1 + (2 * (%no /u 2))) /u 2)
; CHECK: Loop %bb: max backedge-taken count is 1073741822