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

David Sherwood via llvm-commits llvm-commits at lists.llvm.org
Mon Jan 15 07:20:52 PST 2024


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@@ -412,6 +412,16 @@ class AArch64TTIImpl : public BasicTTIImplBase<AArch64TTIImpl> {
 
   bool enableSelectOptimize() { return ST->enableSelectOptimize(); }
 
+  bool shouldTreatInstructionLikeSelect(Instruction *I) {
+    // For the binary operators (e.g. or) we need to be more careful than
+    // selects, here we only transform them if they are already at a natural
+    // break point in the code - the end of a block with an unconditional
+    // terminator.
+    return isa<SelectInst>(I) ||
----------------
david-arm wrote:

Instead of checking for `BinaryOperator` here, do we actually want to explicitly look for `or` instructions instead? I'm just wondering what happens if later on someone extends the SelectLike class in SelectOptimize to cover more binary operators.

I actually wonder if this function should be called directly by SelectLike::match and whether that simplifies the logic a little?

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


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