[flang-commits] [flang] [flang] still apply vectorization cost model with IVDEP (PR #180760)

[Peter Klausler via flang-commits]

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@@ -51,6 +51,9 @@ A list of non-standard directives supported by Flang
   be passed in registers, so it's not clear how lowering should handle this
   case. (Passing scalar actual argument to `ignore_tkr(R)` dummy argument
   that is a scalar with `VALUE` attribute is allowed.)
+* `!dir$ ivdep` asserts that there are no vector dependencies in the following loop,
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klausler wrote:

`CDIR$ IVDEP` historically (in CFT) allowed vectorization in cases of unknown and potentially unsafe dependences, like `A(J)=A(J+K)` where `K` is an unknown loop-invariant value.  For cases like `A(J)=A(J-1)` that really do have an obvious dependence, will `IVDEP` elicit a warning?

https://github.com/llvm/llvm-project/pull/180760