[llvm] [DAG][X86]added shrd in combineor for bzhiq+shlq+or (PR #125734)

[Simon Pilgrim via llvm-commits]

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@@ -51887,6 +51887,47 @@ static SDValue combineOr(SDNode *N, SelectionDAG &DAG,
     }
   }
 
+  if (!Subtarget.isSHLDSlow()) {
+    using namespace llvm::SDPatternMatch;
+    APInt MaskConst, ShlConst;
+    SDValue A, B;
+    if (sd_match(N, m_Or(m_Shl(m_Value(B), m_ConstInt(ShlConst)),
+                         m_And(m_Value(A), m_ConstInt(MaskConst))))) {
+      uint64_t ShiftValue = ShlConst.getZExtValue();
+      if (MaskConst.isMask(ShiftValue) && (A.getOpcode() == ISD::CopyFromReg) &&
+          (B.getOpcode() == ISD::CopyFromReg)) {
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RKSimon wrote:

Using CopyFromReg feels like you're trying to prevent regressions on something?

https://github.com/llvm/llvm-project/pull/125734