[llvm] [SROA] Support promoting small float array partitions to legal integer types (PR #219125)

[Yonah Goldberg via llvm-commits]

https://github.com/YonahGoldberg created https://github.com/llvm/llvm-project/pull/219125

None

>From 7d30578ad34880ce21e38b2d3721411f5901ee40 Mon Sep 17 00:00:00 2001
From: Yonah Goldberg <ygoldberg at nvidia.com>
Date: Thu, 27 Aug 2026 06:10:21 +0000
Subject: [PATCH] [SROA] Prefer legal integers for floating-point arrays

---
 llvm/lib/Transforms/Scalar/SROA.cpp | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index e4770154e2998..4623da0814105 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -5458,11 +5458,12 @@ selectPartitionType(Partition &P, const DataLayout &DL, AllocaInst &AI,
   // type?
   if (Type *TypePartitionTy = getTypePartition(DL, AI.getAllocatedType(),
                                                P.beginOffset(), P.size())) {
-    // If the partition is an integer array that can be spanned by a legal
-    // integer type, prefer to represent it as a legal integer type because
-    // it's more likely to be promotable.
+    // If the partition is an integer or floating-point array that can be
+    // spanned by a legal integer type, prefer to represent it as a legal
+    // integer type because it's more likely to be promotable.
     if (TypePartitionTy->isArrayTy() &&
-        TypePartitionTy->getArrayElementType()->isIntegerTy() &&
+        (TypePartitionTy->getArrayElementType()->isIntegerTy() ||
+         TypePartitionTy->getArrayElementType()->isFloatingPointTy()) &&
         DL.isLegalInteger(P.size() * 8))
       TypePartitionTy = Type::getIntNTy(C, P.size() * 8);
     // There was no common type used, so we prefer integer widening promotion.