[llvm] [DA] Replace delinearization for fixed size array (PR #161822)

[Ryotaro Kasuga via llvm-commits]

https://github.com/kasuga-fj created https://github.com/llvm/llvm-project/pull/161822

Replace the delinearization that depends on type information in GEPs with what doesn't rely on it.

This is WIP as the failing tests need to be updated.

>From 614ffa48bf98c7db99cca442c882c70f2e29ab62 Mon Sep 17 00:00:00 2001
From: Ryotaro Kasuga <kasuga.ryotaro at fujitsu.com>
Date: Fri, 3 Oct 2025 10:34:08 +0000
Subject: [PATCH] [DA] Replace delinearization for fixed size array

---
 llvm/lib/Analysis/DependenceAnalysis.cpp | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 1f0da8d1830d3..46803b6657510 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -3504,12 +3504,13 @@ bool DependenceInfo::tryDelinearizeFixedSize(
            "expected src and dst scev unknowns to be equal");
   });
 
-  SmallVector<int, 4> SrcSizes;
-  SmallVector<int, 4> DstSizes;
-  if (!tryDelinearizeFixedSizeImpl(SE, Src, SrcAccessFn, SrcSubscripts,
-                                   SrcSizes) ||
-      !tryDelinearizeFixedSizeImpl(SE, Dst, DstAccessFn, DstSubscripts,
-                                   DstSizes))
+  const SCEV *ElemSize = SE->getElementSize(Src);
+  assert(ElemSize == SE->getElementSize(Dst) && "Different element sizes");
+  SmallVector<const SCEV *, 4> SrcSizes, DstSizes;
+  if (!delinearizeFixedSizeArray(*SE, SE->removePointerBase(SrcAccessFn),
+                                 SrcSubscripts, SrcSizes, ElemSize) ||
+      !delinearizeFixedSizeArray(*SE, SE->removePointerBase(DstAccessFn),
+                                 DstSubscripts, DstSizes, ElemSize))
     return false;
 
   // Check that the two size arrays are non-empty and equal in length and
@@ -3535,7 +3536,7 @@ bool DependenceInfo::tryDelinearizeFixedSize(
   // iff the subscripts are positive and are less than the range of the
   // dimension.
   if (!DisableDelinearizationChecks) {
-    auto AllIndicesInRange = [&](SmallVector<int, 4> &DimensionSizes,
+    auto AllIndicesInRange = [&](ArrayRef<const SCEV *> DimensionSizes,
                                  SmallVectorImpl<const SCEV *> &Subscripts,
                                  Value *Ptr) {
       size_t SSize = Subscripts.size();
@@ -3549,8 +3550,7 @@ bool DependenceInfo::tryDelinearizeFixedSize(
           return false;
         }
         if (auto *SType = dyn_cast<IntegerType>(S->getType())) {
-          const SCEV *Range = SE->getConstant(
-              ConstantInt::get(SType, DimensionSizes[I - 1], false));
+          const SCEV *Range = DimensionSizes[I - 1];
           if (!isKnownLessThan(S, Range)) {
             LLVM_DEBUG({
               dbgs() << "Check failed: !isKnownLessThan(S, Range)\n";