1 files changed, 41 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 8297260cb1e..faae4a836bb 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -3390,6 +3390,47 @@ bool TypePromotionHelper::canGetThrough(const Instruction *Inst,
        (IsSExt && BinOp->hasNoSignedWrap())))
     return true;
 
+  // ext(and(opnd, cst)) --> and(ext(opnd), ext(cst))
+  if ((Inst->getOpcode() == Instruction::And ||
+       Inst->getOpcode() == Instruction::Or))
+    return true;
+
+  // ext(xor(opnd, cst)) --> xor(ext(opnd), ext(cst))
+  if (Inst->getOpcode() == Instruction::Xor) {
+    const ConstantInt *Cst = dyn_cast<ConstantInt>(Inst->getOperand(1));
+    // Make sure it is not a NOT.
+    if (Cst && !Cst->getValue().isAllOnesValue())
+      return true;
+  }
+
+  // zext(shrl(opnd, cst)) --> shrl(zext(opnd), zext(cst))
+  // It may change a poisoned value into a regular value, like
+  //     zext i32 (shrl i8 %val, 12)  -->  shrl i32 (zext i8 %val), 12
+  //          poisoned value                    regular value
+  // It should be OK since undef covers valid value.
+  if (Inst->getOpcode() == Instruction::LShr && !IsSExt)
+    return true;
+
+  // and(ext(shl(opnd, cst)), cst) --> and(shl(ext(opnd), ext(cst)), cst)
+  // It may change a poisoned value into a regular value, like
+  //     zext i32 (shl i8 %val, 12)  -->  shl i32 (zext i8 %val), 12
+  //          poisoned value                    regular value
+  // It should be OK since undef covers valid value.
+  if (Inst->getOpcode() == Instruction::Shl && Inst->hasOneUse()) {
+    const Instruction *ExtInst =
+        dyn_cast<const Instruction>(*Inst->user_begin());
+    if (ExtInst->hasOneUse()) {
+      const Instruction *AndInst =
+          dyn_cast<const Instruction>(*ExtInst->user_begin());
+      if (AndInst && AndInst->getOpcode() == Instruction::And) {
+        const ConstantInt *Cst = dyn_cast<ConstantInt>(AndInst->getOperand(1));
+        if (Cst &&
+            Cst->getValue().isIntN(Inst->getType()->getIntegerBitWidth()))
+          return true;
+      }
+    }
+  }
+
   // Check if we can do the following simplification.
   // ext(trunc(opnd)) --> ext(opnd)
   if (!isa<TruncInst>(Inst))