[llvm] [DAG] Support saturated truncate (PR #99418)

[Craig Topper via llvm-commits]

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@@ -14915,6 +14920,159 @@ SDValue DAGCombiner::visitEXTEND_VECTOR_INREG(SDNode *N) {
   return SDValue();
 }
 
+SDValue DAGCombiner::visitTRUNCATE_USAT(SDNode *N) {
+  EVT VT = N->getValueType(0);
+  SDValue N0 = N->getOperand(0);
+  SDValue FPInstr = N0.getOpcode() == ISD::SMAX ? N0.getOperand(0) : N0;
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topperc wrote:

Do you need to check the other operand of this SMAX?

https://github.com/llvm/llvm-project/pull/99418