[llvm] [LSR] Recognize vscale-relative immediates (PR #88124)

[Sam Tebbs via llvm-commits]

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@@ -1698,47 +1786,53 @@ static bool isAMCompletelyFolded(const TargetTransformInfo &TTI,
 
     // If we have low-level target information, ask the target if it can fold an
     // integer immediate on an icmp.
-    if (BaseOffset != 0) {
+    if (BaseOffset.isNonZero()) {
       // We have one of:
       // ICmpZero     BaseReg + BaseOffset => ICmp BaseReg, -BaseOffset
       // ICmpZero -1*ScaleReg + BaseOffset => ICmp ScaleReg, BaseOffset
       // Offs is the ICmp immediate.
       if (Scale == 0)
         // The cast does the right thing with
         // std::numeric_limits<int64_t>::min().
-        BaseOffset = -(uint64_t)BaseOffset;
-      return TTI.isLegalICmpImmediate(BaseOffset);
+        BaseOffset = BaseOffset.getFixed((uint64_t)BaseOffset.getFixedValue());
+      return TTI.isLegalICmpImmediate(BaseOffset.getFixedValue());
     }
 
     // ICmpZero BaseReg + -1*ScaleReg => ICmp BaseReg, ScaleReg
     return true;
 
   case LSRUse::Basic:
     // Only handle single-register values.
-    return !BaseGV && Scale == 0 && BaseOffset == 0;
+    return !BaseGV && Scale == 0 && BaseOffset.isZero();
 
   case LSRUse::Special:
     // Special case Basic to handle -1 scales.
-    return !BaseGV && (Scale == 0 || Scale == -1) && BaseOffset == 0;
+    return !BaseGV && (Scale == 0 || Scale == -1) && BaseOffset.isZero();
   }
 
   llvm_unreachable("Invalid LSRUse Kind!");
 }
 
 static bool isAMCompletelyFolded(const TargetTransformInfo &TTI,
-                                 int64_t MinOffset, int64_t MaxOffset,
+                                 Immediate MinOffset, Immediate MaxOffset,
                                  LSRUse::KindType Kind, MemAccessTy AccessTy,
-                                 GlobalValue *BaseGV, int64_t BaseOffset,
+                                 GlobalValue *BaseGV, Immediate BaseOffset,
                                  bool HasBaseReg, int64_t Scale) {
+  if (BaseOffset.isNonZero() &&
+      (BaseOffset.isScalable() != MinOffset.isScalable() ||
+       BaseOffset.isScalable() != MaxOffset.isScalable()))
+    return false;
+  // Check for overflow.
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SamTebbs33 wrote:

Duplicate comment here.

https://github.com/llvm/llvm-project/pull/88124