Index: lib/Transforms/Scalar/LoopStrengthReduce.cpp
===================================================================
--- lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3423,6 +3423,12 @@
   if (AddOps.size() == 1)
     return;
 
+  // For AllFixupsOutsideLoop uses, their reassociations have less impact than
+  // normal uses since they are outside of current loop.
+  // Arbitrarily choose a cap size of AddOps to protect compile time.
+  if (AddOps.size() >= 5 && LU.AllFixupsOutsideLoop)
+    return;
+
   for (SmallVectorImpl<const SCEV *>::const_iterator J = AddOps.begin(),
                                                      JE = AddOps.end();
        J != JE; ++J) {
Index: test/Transforms/LoopStrengthReduce/X86/reassociation-cap.ll
===================================================================
--- test/Transforms/LoopStrengthReduce/X86/reassociation-cap.ll
+++ test/Transforms/LoopStrengthReduce/X86/reassociation-cap.ll
@@ -0,0 +1,111 @@
+; REQUIRES: asserts
+; RUN: opt -mtriple=x86_64-unknown-linux-gnu -loop-reduce -disable-output -debug-only=loop-reduce -S < %s 2>&1| FileCheck %s
+; PR32043. Check LSR will not generate many formulae via reassociation for
+; all-fixups-outside-loop type LSRUse.
+
+; CHECK: LSR on loop %bb15:
+; CHECK: After generating reuse formulae:
+; CHECK: LSR Use: Kind=Basic, Offsets={0}, all-fixups-outside-loop, widest fixup type: i64
+; CHECK-NEXT: reg((-4 * (%tmp34 + %tmp27 + %tmp20 + %tmp13 + %tmp6)))
+; CHECK-NEXT: reg((-4 * (%tmp34 + %tmp27 + %tmp20 + %tmp13 + %tmp6)))
+; CHECK-NEXT: reg((-4 * (%tmp34 + %tmp27 + %tmp20 + %tmp13 + %tmp6)))
+; CHECK-NEXT: LSR Use: Kind=Basic, Offsets={0}, all-fixups-outside-loop, widest fixup type: i64
+; CHECK: LSR on loop %bb12:
+; After put a cap on reassociation for all-fixups-outside-loop type LSRUse, LSR will only
+; generate two reuse formulae for LSRUse %tmp563 used in store.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+
+define void @foo(i64* %arg) {
+bb:
+  br label %bb3
+bb2:
+  %tmp2 = add nuw nsw i64 %tmp1, 1
+  %tmp7 = icmp slt i64 %tmp1, 29
+  br i1 %tmp7, label %bb3, label %bb4
+bb3:
+  %tmp1 = phi i64 [ %tmp2, %bb2 ], [ 0, %bb ]
+  %tmp3 = phi i32 [ %tmp4, %bb2 ], [ 0, %bb ]
+  %tmp5 = getelementptr inbounds i64, i64* %arg, i64 %tmp1
+  %tmp6 = load i64, i64* %tmp5, align 1
+  %tmp4 = add nuw nsw i32 %tmp3, 1
+  br i1 false, label %bb4, label %bb2
+bb4:
+  %tmp90 = sext i32 %tmp4 to i64
+  br label %bb6
+
+bb5:
+  %tmp9 = add nuw nsw i64 %tmp8, 1
+  %tmp14 = icmp slt i64 %tmp8, 29
+  br i1 %tmp14, label %bb6, label %bb7
+bb6:
+  %tmp8 = phi i64 [ %tmp9, %bb5 ], [ 0, %bb4 ]
+  %tmp10 = phi i32 [ %tmp11, %bb5 ], [ 0, %bb4 ]
+  %tmp12 = getelementptr inbounds i64, i64* %arg, i64 %tmp8
+  %tmp13 = load i64, i64* %tmp12, align 1
+  %tmp11 = add nuw nsw i32 %tmp10, 1
+  br i1 false, label %bb7, label %bb5
+bb7:
+  %tmp91 = sext i32 %tmp11 to i64
+  br label %bb9
+
+bb8:
+  %tmp16 = add nuw nsw i64 %tmp15, 1
+  %tmp21 = icmp slt i64 %tmp15, 29
+  br i1 %tmp21, label %bb9, label %bb10
+bb9:
+  %tmp15 = phi i64 [ %tmp16, %bb8 ], [ 0, %bb7 ]
+  %tmp17 = phi i32 [ %tmp18, %bb8 ], [ 0, %bb7 ]
+  %tmp19 = getelementptr inbounds i64, i64* %arg, i64 %tmp15
+  %tmp20 = load i64, i64* %tmp19, align 1
+  %tmp18 = add nuw nsw i32 %tmp17, 1
+  br i1 false, label %bb10, label %bb8
+bb10:
+  %tmp92 = sext i32 %tmp18 to i64
+  br label %bb12
+
+bb11:
+  %tmp23 = add nuw nsw i64 %tmp22, 1
+  %tmp28 = icmp slt i64 %tmp22, 29
+  br i1 %tmp28, label %bb12, label %bb13
+bb12:
+  %tmp22 = phi i64 [ %tmp23, %bb11 ], [ 0, %bb10 ]
+  %tmp24 = phi i32 [ %tmp25, %bb11 ], [ 0, %bb10 ]
+  %tmp26 = getelementptr inbounds i64, i64* %arg, i64 %tmp22
+  %tmp27 = load i64, i64* %tmp26, align 1
+  %tmp25 = add nuw nsw i32 %tmp24, 1
+  br i1 false, label %bb13, label %bb11
+bb13:
+  %tmp93 = sext i32 %tmp25 to i64
+  br label %bb15
+
+bb14:
+  %tmp30 = add nuw nsw i64 %tmp29, 1
+  %tmp35 = icmp slt i64 %tmp29, 29
+  br i1 %tmp35, label %bb15, label %bb16
+bb15:
+  %tmp29 = phi i64 [ %tmp30, %bb14 ], [ 0, %bb13 ]
+  %tmp31 = phi i32 [ %tmp32, %bb14 ], [ 0, %bb13 ]
+  %tmp33 = getelementptr inbounds i64, i64* %arg, i64 %tmp29
+  %tmp34 = load i64, i64* %tmp33, align 1
+  %tmp32 = add nuw nsw i32 %tmp31, 1
+  br i1 false, label %bb16, label %bb14
+bb16:
+  %tmp94 = sext i32 %tmp32 to i64
+  br label %bb556
+
+bb556:
+  %tmp554 = add i64 %tmp6, %tmp13
+  %tmp555 = add i64 %tmp554, %tmp20
+  %tmp556 = add i64 %tmp555, %tmp27
+  %tmp557 = add i64 %tmp556, %tmp34
+  %tmp558 = mul i64 %tmp557, -4
+  %tmp559 = add i64 %tmp558, %tmp90
+  %tmp560 = add i64 %tmp559, %tmp91
+  %tmp561 = add i64 %tmp560, %tmp92
+  %tmp562 = add i64 %tmp561, %tmp93
+  %tmp563 = add i64 %tmp562, %tmp94
+  store i64 %tmp563, i64* %arg, align 8
+  ret void
+}
+