diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -490,6 +490,9 @@
   FPM.addPass(createFunctionToLoopPassAdaptor(
       std::move(LPM2), /*UseMemorySSA=*/false, DebugLogging));
 
+  // Delete small array after loop unroll.
+  FPM.addPass(SROA());
+
   // Eliminate redundancies.
   if (Level != O1) {
     // These passes add substantial compile time so skip them at O1.
diff --git a/llvm/test/Other/new-pm-defaults.ll b/llvm/test/Other/new-pm-defaults.ll
--- a/llvm/test/Other/new-pm-defaults.ll
+++ b/llvm/test/Other/new-pm-defaults.ll
@@ -179,6 +179,7 @@
 ; CHECK-O-NEXT: Running pass: LoopFullUnrollPass
 ; CHECK-EP-LOOP-END-NEXT: Running pass: NoOpLoopPass
 ; CHECK-O-NEXT: Finished Loop pass manager run.
+; CHECK-O-NEXT: Running pass: SROA on foo
 ; CHECK-Os-NEXT: Running pass: MergedLoadStoreMotionPass
 ; CHECK-Os-NEXT: Running pass: GVN
 ; CHECK-Os-NEXT: Running analysis: MemoryDependenceAnalysis
diff --git a/llvm/test/Other/new-pm-thinlto-defaults.ll b/llvm/test/Other/new-pm-thinlto-defaults.ll
--- a/llvm/test/Other/new-pm-thinlto-defaults.ll
+++ b/llvm/test/Other/new-pm-thinlto-defaults.ll
@@ -156,6 +156,7 @@
 ; CHECK-O-NEXT: Running pass: LoopDeletionPass
 ; CHECK-O-NEXT: Running pass: LoopFullUnrollPass
 ; CHECK-O-NEXT: Finished Loop pass manager run.
+; CHECK-O-NEXT: Running pass: SROA on foo
 ; CHECK-Os-NEXT: Running pass: MergedLoadStoreMotionPass
 ; CHECK-Os-NEXT: Running pass: GVN
 ; CHECK-Os-NEXT: Running analysis: MemoryDependenceAnalysis
diff --git a/llvm/test/Other/unroll-sroa.ll b/llvm/test/Other/unroll-sroa.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Other/unroll-sroa.ll
@@ -0,0 +1,61 @@
+; RUN: opt -disable-verify -passes='default<O2>' -S < %s | FileCheck %s
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; The local array %tmp can only be optimized away by sroa after loop unroll.
+
+; CHECK-LABEL: define void @foo
+; CHECK-NOT:   alloca
+; CHECK-NOT:   call void @llvm.memcpy.p0i8.p0i8.i64
+
+; Function Attrs: nounwind uwtable
+define void @foo(i32* %a, i32* %b) {
+entry:
+  %a.addr = alloca i32*, align 8
+  %b.addr = alloca i32*, align 8
+  %tmp = alloca [4 x float], align 16
+  %i = alloca i32, align 4
+  store i32* %a, i32** %a.addr, align 8
+  store i32* %b, i32** %b.addr, align 8
+  store i32 0, i32* %i, align 4
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.inc, %entry
+  %iter2 = load i32, i32* %i, align 4
+  %cmp = icmp slt i32 %iter2, 4
+  br i1 %cmp, label %for.body, label %for.cond.cleanup
+
+for.cond.cleanup:                                 ; preds = %for.cond
+  br label %for.end
+
+for.body:                                         ; preds = %for.cond
+  %inptr = load i32*, i32** %a.addr, align 8
+  %idx2 = load i32, i32* %i, align 4
+  %idxprom = sext i32 %idx2 to i64
+  %arrayidx = getelementptr inbounds i32, i32* %inptr, i64 %idxprom
+  %val = load i32, i32* %arrayidx, align 4
+  %conv = sitofp i32 %val to float
+  %idx = load i32, i32* %i, align 4
+  %idxprom1 = sext i32 %idx to i64
+  %arrayidx2 = getelementptr inbounds [4 x float], [4 x float]* %tmp, i64 0, i64 %idxprom1
+  store float %conv, float* %arrayidx2, align 4
+  br label %for.inc
+
+for.inc:                                          ; preds = %for.body
+  %iter = load i32, i32* %i, align 4
+  %inc = add nsw i32 %iter, 1
+  store i32 %inc, i32* %i, align 4
+  br label %for.cond
+
+for.end:                                          ; preds = %for.cond.cleanup
+  %dstptr = load i32*, i32** %b.addr, align 8
+  %dst = bitcast i32* %dstptr to i8*
+  %arraydecay = getelementptr inbounds [4 x float], [4 x float]* %tmp, i64 0, i64 0
+  %src = bitcast float* %arraydecay to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* align 4 %dst, i8* align 16 %src, i64 16, i1 false)
+  ret void
+}
+
+; Function Attrs: argmemonly nounwind willreturn
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* noalias nocapture writeonly, i8* noalias nocapture readonly, i64, i1 immarg)