[PATCH] D139630: [InstCombine] Fold logic-and/logic-or by distributive laws part2

[chenglin.bi via Phabricator via llvm-commits]

bcl5980 added inline comments.


================
Comment at: llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp:2801
       bool FalseLogicAnd = isa<SelectInst>(FalseVal);
-      if (CondLogicAnd && FalseLogicAnd) {
-        // (A ? B : 0) ? 1 : (A ? D : 0) --> A ? (B ? 1 : D) : 0
+      auto AndFactorization = [&](Value *Common, Value *InnerCond,
+                                  Value *InnerVal,
----------------
spatel wrote:
> Can we add some description of the different possibilities? 
> 
> I know that handling all of the patterns poison-safely is not uniform, but what if we use freeze to make it safe with regular logic ops instead:
> https://alive2.llvm.org/ce/z/xb_moG
> 
> There is an existing code example for a similar transform below this block of code - search for "MayNeedFreeze".
> 
> 
So which way are you prefer now? Not uniform code without freeze instruction or use freeze asap to make code easier?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D139630/new/

https://reviews.llvm.org/D139630