search for: getopaqueexpr

...e interpretations of a specific solution. > Adding simplification barriers into SCEV expressions seems like a > dangerous idea, especially since LSR is not the only user of SCEV. So I don't intend for SCEV to produce SCEVOpaqueExpr nodes itself. There would instead be a 'const SCEV *getOpaqueExpr(const SCEV *)' function that clients of SCEV can use to create an opaque expression. Then most of the simplification routines SCEV will be changed to have the moral equivalent of 'if (isa<SCEVOpaqueExpr>(E)) continue;'. -- Sanjoy [1]: http://lists.llvm.org/pipermail/llvm-dev/201...

This is related to an issue in loop strength reduction [1] that I've been trying to fix on and off for a while. [1] has a more detailed description of the issue and an example, but briefly put, I want LSR to consider formulae that have "Zext T" as base and/or scale registers, and to appropriately rate such formulae. My first attempt[2] at fixing this was buggy and had to be