[llvm] [RISCV] Porting hasAllNBitUsers to RISCV GISel for instruction select (PR #124678)

[Luke Quinn via llvm-commits]

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@@ -186,6 +199,169 @@ RISCVInstructionSelector::RISCVInstructionSelector(
 {
 }
 
+bool RISCVInstructionSelector::hasAllNBitUsers(const MachineInstr &MI,
+                                               unsigned Bits,
+                                               const unsigned Depth) const {
+
+  assert((MI.getOpcode() == TargetOpcode::G_ADD ||
+          MI.getOpcode() == TargetOpcode::G_SUB ||
+          MI.getOpcode() == TargetOpcode::G_MUL ||
+          MI.getOpcode() == TargetOpcode::G_SHL ||
+          MI.getOpcode() == TargetOpcode::G_LSHR ||
+          MI.getOpcode() == TargetOpcode::G_AND ||
+          MI.getOpcode() == TargetOpcode::G_OR ||
+          MI.getOpcode() == TargetOpcode::G_XOR ||
+          MI.getOpcode() == TargetOpcode::G_SEXT_INREG || Depth != 0) &&
+         "Unexpected opcode");
+
+  if (Depth >= /*TODO*/ 20)
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lquinn2015 wrote:

Okay I'll add one locally to the follow and set it to 6 

https://github.com/llvm/llvm-project/pull/124678