================
@@ -4216,6 +4217,97 @@ MachineSDNode *X86DAGToDAGISel::emitPCMPESTR(unsigned
ROpc, unsigned MOpc,
return CNode;
}
+// When the consumer of a right shift (arithmetic or logical) wouldn't notice
+// the difference if the instruction was a rotate right instead (because the
+// bits shifted in are truncated away), the shift can be replaced by the RORX
+// instruction from BMI2. This doesn't set flags and can output to a different
+// register. However, this increases code size in most cases, and doesn't leave
+// the high bits in a useful state. There may be other situations where this
+// transformation is profitable given those conditions, but currently the
+// transformation is only made when it likely avoids spilling flags.
+bool X86DAGToDAGISel::rightShiftUncloberFlags(SDNode *N) {
----------------
RKSimon wrote:
typo: rightShiftUncloberFlags -> rightShiftUnclobberFlags
https://github.com/llvm/llvm-project/pull/77964
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