[llvm] [DXIL] Implement pow lowering (PR #86733)

[Joshua Batista via llvm-commits]

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@@ -197,6 +198,26 @@ static bool expandLog10Intrinsic(CallInst *Orig) {
   return expandLogIntrinsic(Orig, numbers::ln2f / numbers::ln10f);
 }
 
+static bool expandPowIntrinsic(CallInst *Orig) {
+
+  Value *X = Orig->getOperand(0);
+  Value *Y = Orig->getOperand(1);
+  Type *Ty = X->getType();
+  IRBuilder<> Builder(Orig->getParent());
+  Builder.SetInsertPoint(Orig);
+
+  auto *Log2Call =
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bob80905 wrote:

These edge cases may be addressed elsewhere, but do we want special cases for when X is 0?
Logs probably won't work when the input base parameter is 0, since it's mathematically undefined to take the log of 0. But, 0^3 should be 0 from a power op point of view. So I wonder if this implementation is sufficient for that edge case.

https://github.com/llvm/llvm-project/pull/86733