[llvm] [SelectOpt] Add handling for Select-like operations. (PR #77284)

[David Green via llvm-commits]

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@@ -368,15 +508,24 @@ void SelectOptimizeImpl::optimizeSelectsInnerLoops(Function &F,
 /// select instructions in \p Selects, look through the defining select
 /// instruction until the true/false value is not defined in \p Selects.
 static Value *
-getTrueOrFalseValue(SelectInst *SI, bool isTrue,
-                    const SmallPtrSet<const Instruction *, 2> &Selects) {
+getTrueOrFalseValue(SelectOptimizeImpl::SelectLike SI, bool isTrue,
+                    const SmallPtrSet<const Instruction *, 2> &Selects,
+                    IRBuilder<> &IB) {
   Value *V = nullptr;
-  for (SelectInst *DefSI = SI; DefSI != nullptr && Selects.count(DefSI);
+  for (SelectInst *DefSI = dyn_cast<SelectInst>(SI.getSI());
+       DefSI != nullptr && Selects.count(DefSI);
        DefSI = dyn_cast<SelectInst>(V)) {
-    assert(DefSI->getCondition() == SI->getCondition() &&
+    assert(DefSI->getCondition() == SI.getCondition() &&
            "The condition of DefSI does not match with SI");
     V = (isTrue ? DefSI->getTrueValue() : DefSI->getFalseValue());
   }
+
+  if (isa<BinaryOperator>(SI.getSI())) {
+    V = SI.getFalseValue();
+    if (isTrue)
+      V = IB.CreateOr(V, ConstantInt::get(V->getType(), 1));
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davemgreen wrote:

Yep good point - it's assuming that it is an Or at the moment. (Treating some other binary operations like selects would also work, but may or may not be profitable and I'm trying to keep the changes to a minimum). I can try and make it more explicit about it being an Or.

https://github.com/llvm/llvm-project/pull/77284