[llvm] [AArch64][GISel] Support SVE with 128-bit min-size for G_LOAD and G_STORE (PR #92130)

[Thorsten Schütt via llvm-commits]

================
@@ -61,6 +61,79 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
   const LLT v2s64 = LLT::fixed_vector(2, 64);
   const LLT v2p0 = LLT::fixed_vector(2, p0);
 
+  // Scalable vector sizes range from 128 to 2048
+  // Note that subtargets may not support the full range.
+  // See [ScalableVecTypes] below.
+  const LLT nxv16s8 = LLT::scalable_vector(16, s8);
+  const LLT nxv32s8 = LLT::scalable_vector(32, s8);
+  const LLT nxv64s8 = LLT::scalable_vector(64, s8);
+  const LLT nxv128s8 = LLT::scalable_vector(128, s8);
+  const LLT nxv256s8 = LLT::scalable_vector(256, s8);
----------------
tschuett wrote:

This is a scalable vector, which size is an unknown multiple of 256 * 8. Legalizing loads of scalable vectors is unintuitive.

https://github.com/llvm/llvm-project/pull/92130