[llvm] [LAA] Prepare to handle diff type sizes v2 (PR #161238)

[Florian Hahn via llvm-commits]

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@@ -2267,32 +2286,22 @@ MemoryDepChecker::isDependent(const MemAccessInfo &A, unsigned AIdx,
   uint64_t ConstDist =
       match(Dist, m_scev_APInt(APDist)) ? APDist->abs().getZExtValue() : 0;
 
-  // Attempt to prove strided accesses independent.
-  if (APDist) {
-    // If the distance between accesses and their strides are known constants,
-    // check whether the accesses interlace each other.
-    if (ConstDist > 0 && CommonStride && CommonStride > 1 && HasSameSize &&
-        areStridedAccessesIndependent(ConstDist, *CommonStride, TypeByteSize)) {
-      LLVM_DEBUG(dbgs() << "LAA: Strided accesses are independent\n");
-      return Dependence::NoDep;
-    }
-  } else {
-    if (!LoopGuards)
-      LoopGuards.emplace(
-          ScalarEvolution::LoopGuards::collect(InnermostLoop, SE));
-    Dist = SE.applyLoopGuards(Dist, *LoopGuards);
+  // Attempt to prove strided accesses independent. If the distance between
+  // accesses and their strides are known constants, check whether the accesses
+  // interlace each other.
+  if (ConstDist && CommonStride && CommonStride > 1 && HasSameSize &&
+      areStridedAccessesIndependent(ConstDist, *CommonStride,
+                                    TypeByteSize.first)) {
+    LLVM_DEBUG(dbgs() << "LAA: Strided accesses are independent\n");
+    return Dependence::NoDep;
   }
 
   // Negative distances are not plausible dependencies.
   if (SE.isKnownNonPositive(Dist)) {
     if (SE.isKnownNonNegative(Dist)) {
-      if (HasSameSize) {
-        // Write to the same location with the same size.
-        return Dependence::Forward;
-      }
-      LLVM_DEBUG(dbgs() << "LAA: possibly zero dependence difference but "
-                           "different type sizes\n");
-      return Dependence::Unknown;
+      // Write to the same location with the same size.
+      assert(HasSameSize && "Accesses must have the same size");
+      return Dependence::Forward;
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fhahn wrote:

can this be split off?

https://github.com/llvm/llvm-project/pull/161238