[llvm] [AArch64][GISel] Add fp128 and i128 sitofp/uitofp handling (PR #97691)

[Dhruv Chawla via llvm-commits]

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@@ -710,34 +710,45 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
           {{s32, s128}, {s64, s128}, {s128, s128}, {s128, s32}, {s128, s64}});
 
   getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
-      .legalForCartesianProduct({s32, s64, v2s64, v4s32, v2s32})
+      .legalFor({{s32, s32},
+             {s64, s32},
+             {s32, s64},
+             {s64, s64},
+             {v2s64, v2s64},
+             {v4s32, v4s32},
+             {v2s32, v2s32}})
       .legalIf([=](const LegalityQuery &Query) {
         return HasFP16 &&
                (Query.Types[0] == s16 || Query.Types[0] == v4s16 ||
                 Query.Types[0] == v8s16) &&
                (Query.Types[1] == s32 || Query.Types[1] == s64 ||
                 Query.Types[1] == v4s16 || Query.Types[1] == v8s16);
       })
-      .widenScalarToNextPow2(1)
-      .clampScalar(1, s32, s64)
-      .widenScalarToNextPow2(0)
-      .clampScalarOrElt(0, MinFPScalar, s64)
-      .moreElementsToNextPow2(0)
+      .scalarizeIf(scalarOrEltWiderThan(1, 64), 1)
+      .scalarizeIf(scalarOrEltWiderThan(0, 64), 0)
+      .moreElementsToNextPow2(1)
+      .widenScalarOrEltToNextPow2OrMinSize(1)
+      .minScalar(1, s32)
+      .widenScalarOrEltToNextPow2OrMinSize(0, /*MinSize=*/HasFP16 ? 16 : 32)
       .widenScalarIf(
           [=](const LegalityQuery &Query) {
-            return Query.Types[0].getScalarSizeInBits() <
-                   Query.Types[1].getScalarSizeInBits();
+            return Query.Types[0].getScalarSizeInBits() <= 64 &&
+                   Query.Types[0].getScalarSizeInBits() >
+                       Query.Types[1].getScalarSizeInBits();
           },
-          LegalizeMutations::changeElementSizeTo(0, 1))
+          LegalizeMutations::changeElementSizeTo(1, 0))
       .widenScalarIf(
           [=](const LegalityQuery &Query) {
-            return Query.Types[0].getScalarSizeInBits() >
-                   Query.Types[1].getScalarSizeInBits();
+            return Query.Types[1].getScalarSizeInBits() <= 64 &&
+                   Query.Types[0].getScalarSizeInBits() <
+                       Query.Types[1].getScalarSizeInBits();
           },
-          LegalizeMutations::changeElementSizeTo(1, 0))
+          LegalizeMutations::changeElementSizeTo(0, 1))
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dc03-work wrote:

I don't think it matters in practice (or at all really), but why were the `changeElementSizeTo` calls swapped?

https://github.com/llvm/llvm-project/pull/97691