[llvm] [AArch64][GISel] Always fold G_SHL into addressing mode where possible, unless the subtarget has addr-lsl-slow-14 (PR #96603)

[Thorsten Schütt via llvm-commits]

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@@ -6717,19 +6722,70 @@ AArch64InstructionSelector::selectNegArithImmed(MachineOperand &Root) const {
   return select12BitValueWithLeftShift(Immed);
 }
 
+/// Checks if we are sure that folding MI into load/store addressing mode is
+/// beneficial or not.
+///
+/// Returns:
+/// - true if fodling MI would be beneficial.
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tschuett wrote:

folding

https://github.com/llvm/llvm-project/pull/96603