[llvm] [InstCombine] Implement vp.reverse elimination through binop/unop (PR #143963)

[Philip Reames via llvm-commits]

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@@ -3582,6 +3582,42 @@ Instruction *InstCombinerImpl::visitCallInst(CallInst &CI) {
     }
     break;
   }
+  case Intrinsic::experimental_vp_reverse: {
+    Value *BO0, *BO1, *X, *Y;
+    Value *Vec = II->getArgOperand(0);
+    Value *Mask = II->getArgOperand(1);
+    Value *EVL = II->getArgOperand(2);
+    auto m_VPReverse = [&](Value *&Vec) {
+      return m_Intrinsic<Intrinsic::experimental_vp_reverse>(
+          m_Value(Vec), m_Specific(Mask), m_Specific(EVL));
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preames wrote:

You're 100% right.  The case I actually care about is a true mask, so I'm going to restrict it to that. 

https://github.com/llvm/llvm-project/pull/143963