1 Analysis Opportunities: 2 3 //===---------------------------------------------------------------------===// 4 5 In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the 6 ScalarEvolution expression for %r is this: 7 8 {1,+,3,+,2}<loop> 9 10 Outside the loop, this could be evaluated simply as (%n * %n), however 11 ScalarEvolution currently evaluates it as 12 13 (-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n)) 14 15 In addition to being much more complicated, it involves i65 arithmetic, 16 which is very inefficient when expanded into code. 17 18 //===---------------------------------------------------------------------===// 19 20 In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll, 21 22 ScalarEvolution is forming this expression: 23 24 ((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32))) 25 26 This could be folded to 27 28 (-1 * (trunc i64 undef to i32)) 29 30 //===---------------------------------------------------------------------===// 31
