[PATCH] D145220: [X86][InstCombine] Simplify some `pternlog` intrinsics

[Noah Goldstein via Phabricator via llvm-commits]

goldstein.w.n marked an inline comment as not done.
goldstein.w.n added inline comments.


================
Comment at: llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp:591-594
+  // Currently we only handle cases that convert directly to another instruction
+  // or cases where all the ops are constant.  This is because we don't properly
+  // handle creating ternary ops in the backend, so splitting them here may
+  // cause regressions. As the backend improves, uncomment more cases.
----------------
goldstein.w.n wrote:
> pengfei wrote:
> > Maybe better to do it in FE and remove all these intrinsics finally?
> What do you mean? Like in the header for `_mm_ternarylogic_....` add a switch statement? Or something else?
> 
> But would prefer to keep it somewhere we have const/non-const info on A/B/C because it will currently cause regressions to simplify many of the cases (working on a patch for backend generation, but a ways away).
> What do you mean? Like in the header for `_mm_ternarylogic_....` add a switch statement? Or something else?
> 
> But would prefer to keep it somewhere we have const/non-const info on A/B/C because it will currently cause regressions to simplify many of the cases (working on a patch for backend generation, but a ways away).

We can handle the constants algorithimically if you prefer (my feeling however is 1 implementation is preferred and if we need the table would be simpler to just use that).


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