Files
clang-p2996/llvm/test/Transforms/LoopVectorize/invariant-store-vectorization-2.ll
Florian Hahn 99d6c6d936 [VPlan] Model branch cond to enter scalar epilogue in VPlan. (#92651)
This patch moves branch condition creation to enter the scalar epilogue
loop to VPlan. Modeling the branch in the middle block also requires
modeling the successor blocks. This is done using the recently
introduced VPIRBasicBlock.

Note that the middle.block is still created as part of the skeleton and
then patched in during VPlan execution. Unfortunately the skeleton needs
to create the middle.block early on, as it is also used for induction
resume value creation and is also needed to properly update the
dominator tree during skeleton creation.

After this patch lands, I plan to move induction resume value and phi
node creation in the scalar preheader to VPlan. Once that is done, we
should be able to create the middle.block in VPlan directly.

This is a re-worked version based on the earlier
https://reviews.llvm.org/D150398 and the main change is the use of
VPIRBasicBlock.

Depends on https://github.com/llvm/llvm-project/pull/92525

PR: https://github.com/llvm/llvm-project/pull/92651
2024-07-05 10:08:42 +01:00

284 lines
16 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -aa-pipeline=basic-aa -passes='loop-mssa(licm),loop-vectorize,dce,instcombine,loop-mssa(licm)' -force-vector-width=4 -S | FileCheck %s
; First licm pass is to hoist/sink invariant stores if possible. Today LICM does
; not hoist/sink the invariant stores. Even if that changes, we should still
; vectorize this loop in case licm is not run.
; The next licm pass after vectorization is to hoist/sink loop invariant
; instructions.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
; This file separates tests with auto-generated check lines from
; invariant-store-vectorization.ll for maintenance.
; all tests check that it is legal to vectorize the stores to invariant
; address.
; Instcombine'd version of @inv_val_store_to_inv_address_conditional_diff_values.
; Now the store is no longer of invariant value.
; scalar store the value extracted from the last element of the vector value.
define void @inv_val_store_to_inv_address_conditional_diff_values_ic(ptr %a, i64 %n, ptr %b, i32 %k) {
; CHECK-LABEL: @inv_val_store_to_inv_address_conditional_diff_values_ic(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[NTRUNC:%.*]] = trunc i64 [[N:%.*]] to i32
; CHECK-NEXT: [[SMAX2:%.*]] = call i64 @llvm.smax.i64(i64 [[N]], i64 1)
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp slt i64 [[N]], 4
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_MEMCHECK:%.*]]
; CHECK: vector.memcheck:
; CHECK-NEXT: [[TMP0:%.*]] = shl i64 [[N]], 2
; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, ptr [[B:%.*]], i64 [[TMP0]]
; CHECK-NEXT: [[SCEVGEP1:%.*]] = getelementptr i8, ptr [[A:%.*]], i64 4
; CHECK-NEXT: [[BOUND0:%.*]] = icmp ugt ptr [[SCEVGEP1]], [[B]]
; CHECK-NEXT: [[BOUND1:%.*]] = icmp ugt ptr [[SCEVGEP]], [[A]]
; CHECK-NEXT: [[FOUND_CONFLICT:%.*]] = and i1 [[BOUND0]], [[BOUND1]]
; CHECK-NEXT: br i1 [[FOUND_CONFLICT]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[SMAX2]], 9223372036854775804
; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[K:%.*]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: [[BROADCAST_SPLATINSERT3:%.*]] = insertelement <4 x i32> poison, i32 [[NTRUNC]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT4:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT3]], <4 x i32> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 8, !alias.scope [[META0:![0-9]+]], !noalias [[META3:![0-9]+]]
; CHECK-NEXT: [[DOTNOT:%.*]] = icmp eq <4 x i32> [[WIDE_LOAD]], [[BROADCAST_SPLAT]]
; CHECK-NEXT: store <4 x i32> [[BROADCAST_SPLAT4]], ptr [[TMP1]], align 4, !alias.scope [[META0]], !noalias [[META3]]
; CHECK-NEXT: [[PREDPHI:%.*]] = select <4 x i1> [[DOTNOT]], <4 x i32> [[BROADCAST_SPLAT4]], <4 x i32> [[BROADCAST_SPLAT]]
; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i32> [[PREDPHI]], i64 3
; CHECK-NEXT: store i32 [[TMP2]], ptr [[A]], align 4, !alias.scope [[META3]]
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT: [[TMP3:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT: br i1 [[TMP3]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP5:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[SMAX2]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ], [ 0, [[VECTOR_MEMCHECK]] ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[LATCH:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[I1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[I]]
; CHECK-NEXT: [[I2:%.*]] = load i32, ptr [[I1]], align 8
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[I2]], [[K]]
; CHECK-NEXT: store i32 [[NTRUNC]], ptr [[I1]], align 4
; CHECK-NEXT: br i1 [[CMP]], label [[COND_STORE:%.*]], label [[COND_STORE_K:%.*]]
; CHECK: cond_store:
; CHECK-NEXT: br label [[LATCH]]
; CHECK: cond_store_k:
; CHECK-NEXT: br label [[LATCH]]
; CHECK: latch:
; CHECK-NEXT: [[STOREVAL:%.*]] = phi i32 [ [[NTRUNC]], [[COND_STORE]] ], [ [[K]], [[COND_STORE_K]] ]
; CHECK-NEXT: store i32 [[STOREVAL]], ptr [[A]], align 4
; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END_LOOPEXIT:%.*]], !llvm.loop [[LOOP8:![0-9]+]]
; CHECK: for.end.loopexit:
; CHECK-NEXT: br label [[FOR_END]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
entry:
%ntrunc = trunc i64 %n to i32
br label %for.body
for.body: ; preds = %for.body, %entry
%i = phi i64 [ %i.next, %latch ], [ 0, %entry ]
%i1 = getelementptr inbounds i32, ptr %b, i64 %i
%i2 = load i32, ptr %i1, align 8
%cmp = icmp eq i32 %i2, %k
store i32 %ntrunc, ptr %i1
br i1 %cmp, label %cond_store, label %cond_store_k
cond_store:
br label %latch
cond_store_k:
br label %latch
latch:
%storeval = phi i32 [ %ntrunc, %cond_store ], [ %k, %cond_store_k ]
store i32 %storeval, ptr %a
%i.next = add nuw nsw i64 %i, 1
%cond = icmp slt i64 %i.next, %n
br i1 %cond, label %for.body, label %for.end
for.end: ; preds = %for.body
ret void
}
; invariant val stored to invariant address predicated on invariant condition
; This is not treated as a predicated store since the block the store belongs to
; is the latch block (which doesn't need to be predicated).
; variant/invariant values being stored to invariant address.
; test checks that the last element of the phi is extracted and scalar stored
; into the uniform address within the loop.
; Since the condition and the phi is loop invariant, they are LICM'ed after
; vectorization.
define void @inv_val_store_to_inv_address_conditional_inv(ptr %a, i64 %n, ptr %b, i32 %k) {
; CHECK-LABEL: @inv_val_store_to_inv_address_conditional_inv(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[NTRUNC:%.*]] = trunc i64 [[N:%.*]] to i32
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[NTRUNC]], [[K:%.*]]
; CHECK-NEXT: [[SMAX2:%.*]] = call i64 @llvm.smax.i64(i64 [[N]], i64 1)
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp slt i64 [[N]], 4
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_MEMCHECK:%.*]]
; CHECK: vector.memcheck:
; CHECK-NEXT: [[TMP0:%.*]] = shl i64 [[N]], 2
; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, ptr [[B:%.*]], i64 [[TMP0]]
; CHECK-NEXT: [[SCEVGEP1:%.*]] = getelementptr i8, ptr [[A:%.*]], i64 4
; CHECK-NEXT: [[BOUND0:%.*]] = icmp ugt ptr [[SCEVGEP1]], [[B]]
; CHECK-NEXT: [[BOUND1:%.*]] = icmp ugt ptr [[SCEVGEP]], [[A]]
; CHECK-NEXT: [[FOUND_CONFLICT:%.*]] = and i1 [[BOUND0]], [[BOUND1]]
; CHECK-NEXT: br i1 [[FOUND_CONFLICT]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[SMAX2]], 9223372036854775804
; CHECK-NEXT: [[BROADCAST_SPLATINSERT:%.*]] = insertelement <4 x i32> poison, i32 [[NTRUNC]], i64 0
; CHECK-NEXT: [[BROADCAST_SPLAT:%.*]] = shufflevector <4 x i32> [[BROADCAST_SPLATINSERT]], <4 x i32> poison, <4 x i32> zeroinitializer
; CHECK-NEXT: [[TMP1:%.*]] = insertelement <4 x i1> poison, i1 [[CMP]], i64 3
; CHECK-NEXT: [[BROADCAST_SPLAT6:%.*]] = insertelement <4 x i32> poison, i32 [[K]], i64 3
; CHECK-NEXT: [[PREDPHI:%.*]] = select <4 x i1> [[TMP1]], <4 x i32> [[BROADCAST_SPLAT]], <4 x i32> [[BROADCAST_SPLAT6]]
; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i32> [[PREDPHI]], i64 3
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP3:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
; CHECK-NEXT: store <4 x i32> [[BROADCAST_SPLAT]], ptr [[TMP3]], align 4, !alias.scope [[META9:![0-9]+]], !noalias [[META12:![0-9]+]]
; CHECK-NEXT: store i32 [[TMP2]], ptr [[A]], align 4, !alias.scope [[META12]]
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT: br i1 [[TMP4]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP14:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[SMAX2]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ], [ 0, [[VECTOR_MEMCHECK]] ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[LATCH:%.*]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[I1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[I]]
; CHECK-NEXT: store i32 [[NTRUNC]], ptr [[I1]], align 4
; CHECK-NEXT: br i1 [[CMP]], label [[COND_STORE:%.*]], label [[COND_STORE_K:%.*]]
; CHECK: cond_store:
; CHECK-NEXT: br label [[LATCH]]
; CHECK: cond_store_k:
; CHECK-NEXT: br label [[LATCH]]
; CHECK: latch:
; CHECK-NEXT: [[STOREVAL:%.*]] = phi i32 [ [[NTRUNC]], [[COND_STORE]] ], [ [[K]], [[COND_STORE_K]] ]
; CHECK-NEXT: store i32 [[STOREVAL]], ptr [[A]], align 4
; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END_LOOPEXIT:%.*]], !llvm.loop [[LOOP15:![0-9]+]]
; CHECK: for.end.loopexit:
; CHECK-NEXT: br label [[FOR_END]]
; CHECK: for.end:
; CHECK-NEXT: ret void
;
entry:
%ntrunc = trunc i64 %n to i32
%cmp = icmp eq i32 %ntrunc, %k
br label %for.body
for.body: ; preds = %for.body, %entry
%i = phi i64 [ %i.next, %latch ], [ 0, %entry ]
%i1 = getelementptr inbounds i32, ptr %b, i64 %i
%i2 = load i32, ptr %i1, align 8
store i32 %ntrunc, ptr %i1
br i1 %cmp, label %cond_store, label %cond_store_k
cond_store:
br label %latch
cond_store_k:
br label %latch
latch:
%storeval = phi i32 [ %ntrunc, %cond_store ], [ %k, %cond_store_k ]
store i32 %storeval, ptr %a
%i.next = add nuw nsw i64 %i, 1
%cond = icmp slt i64 %i.next, %n
br i1 %cond, label %for.body, label %for.end
for.end: ; preds = %for.body
ret void
}
; variant value stored to uniform address tests that the code gen extracts the
; last element from the variant vector and scalar stores it into the uniform
; address.
define i32 @variant_val_store_to_inv_address(ptr %a, i64 %n, ptr %b, i32 %k) {
; CHECK-LABEL: @variant_val_store_to_inv_address(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[SMAX2:%.*]] = call i64 @llvm.smax.i64(i64 [[N:%.*]], i64 1)
; CHECK-NEXT: [[MIN_ITERS_CHECK:%.*]] = icmp slt i64 [[N]], 4
; CHECK-NEXT: br i1 [[MIN_ITERS_CHECK]], label [[SCALAR_PH:%.*]], label [[VECTOR_MEMCHECK:%.*]]
; CHECK: vector.memcheck:
; CHECK-NEXT: [[SCEVGEP:%.*]] = getelementptr i8, ptr [[A:%.*]], i64 4
; CHECK-NEXT: [[TMP0:%.*]] = shl i64 [[N]], 2
; CHECK-NEXT: [[SCEVGEP1:%.*]] = getelementptr i8, ptr [[B:%.*]], i64 [[TMP0]]
; CHECK-NEXT: [[BOUND0:%.*]] = icmp ugt ptr [[SCEVGEP1]], [[A]]
; CHECK-NEXT: [[BOUND1:%.*]] = icmp ugt ptr [[SCEVGEP]], [[B]]
; CHECK-NEXT: [[FOUND_CONFLICT:%.*]] = and i1 [[BOUND0]], [[BOUND1]]
; CHECK-NEXT: br i1 [[FOUND_CONFLICT]], label [[SCALAR_PH]], label [[VECTOR_PH:%.*]]
; CHECK: vector.ph:
; CHECK-NEXT: [[N_VEC:%.*]] = and i64 [[SMAX2]], 9223372036854775804
; CHECK-NEXT: br label [[VECTOR_BODY:%.*]]
; CHECK: vector.body:
; CHECK-NEXT: [[INDEX:%.*]] = phi i64 [ 0, [[VECTOR_PH]] ], [ [[INDEX_NEXT:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[VEC_PHI:%.*]] = phi <4 x i32> [ zeroinitializer, [[VECTOR_PH]] ], [ [[TMP3:%.*]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[INDEX]]
; CHECK-NEXT: [[WIDE_LOAD:%.*]] = load <4 x i32>, ptr [[TMP1]], align 8, !alias.scope [[META16:![0-9]+]]
; CHECK-NEXT: [[TMP2:%.*]] = extractelement <4 x i32> [[WIDE_LOAD]], i64 3
; CHECK-NEXT: store i32 [[TMP2]], ptr [[A]], align 4, !alias.scope [[META19:![0-9]+]], !noalias [[META16]]
; CHECK-NEXT: [[TMP3]] = add <4 x i32> [[VEC_PHI]], [[WIDE_LOAD]]
; CHECK-NEXT: [[INDEX_NEXT]] = add nuw i64 [[INDEX]], 4
; CHECK-NEXT: [[TMP4:%.*]] = icmp eq i64 [[INDEX_NEXT]], [[N_VEC]]
; CHECK-NEXT: br i1 [[TMP4]], label [[MIDDLE_BLOCK:%.*]], label [[VECTOR_BODY]], !llvm.loop [[LOOP21:![0-9]+]]
; CHECK: middle.block:
; CHECK-NEXT: [[DOTLCSSA:%.*]] = phi <4 x i32> [ [[TMP3]], [[VECTOR_BODY]] ]
; CHECK-NEXT: [[TMP5:%.*]] = call i32 @llvm.vector.reduce.add.v4i32(<4 x i32> [[DOTLCSSA]])
; CHECK-NEXT: [[CMP_N:%.*]] = icmp eq i64 [[SMAX2]], [[N_VEC]]
; CHECK-NEXT: br i1 [[CMP_N]], label [[FOR_END:%.*]], label [[SCALAR_PH]]
; CHECK: scalar.ph:
; CHECK-NEXT: [[BC_RESUME_VAL:%.*]] = phi i64 [ [[N_VEC]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY:%.*]] ], [ 0, [[VECTOR_MEMCHECK]] ]
; CHECK-NEXT: [[BC_MERGE_RDX:%.*]] = phi i32 [ [[TMP5]], [[MIDDLE_BLOCK]] ], [ 0, [[ENTRY]] ], [ 0, [[VECTOR_MEMCHECK]] ]
; CHECK-NEXT: br label [[FOR_BODY:%.*]]
; CHECK: for.body:
; CHECK-NEXT: [[I:%.*]] = phi i64 [ [[I_NEXT:%.*]], [[FOR_BODY]] ], [ [[BC_RESUME_VAL]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[I0:%.*]] = phi i32 [ [[I3:%.*]], [[FOR_BODY]] ], [ [[BC_MERGE_RDX]], [[SCALAR_PH]] ]
; CHECK-NEXT: [[I1:%.*]] = getelementptr inbounds i32, ptr [[B]], i64 [[I]]
; CHECK-NEXT: [[I2:%.*]] = load i32, ptr [[I1]], align 8
; CHECK-NEXT: store i32 [[I2]], ptr [[A]], align 4
; CHECK-NEXT: [[I3]] = add i32 [[I0]], [[I2]]
; CHECK-NEXT: [[I_NEXT]] = add nuw nsw i64 [[I]], 1
; CHECK-NEXT: [[COND:%.*]] = icmp slt i64 [[I_NEXT]], [[N]]
; CHECK-NEXT: br i1 [[COND]], label [[FOR_BODY]], label [[FOR_END_LOOPEXIT:%.*]], !llvm.loop [[LOOP22:![0-9]+]]
; CHECK: for.end.loopexit:
; CHECK-NEXT: [[I3_LCSSA:%.*]] = phi i32 [ [[I3]], [[FOR_BODY]] ]
; CHECK-NEXT: br label [[FOR_END]]
; CHECK: for.end:
; CHECK-NEXT: [[RDX_LCSSA:%.*]] = phi i32 [ [[TMP5]], [[MIDDLE_BLOCK]] ], [ [[I3_LCSSA]], [[FOR_END_LOOPEXIT]] ]
; CHECK-NEXT: ret i32 [[RDX_LCSSA]]
;
entry:
%ntrunc = trunc i64 %n to i32
%cmp = icmp eq i32 %ntrunc, %k
br label %for.body
for.body: ; preds = %for.body, %entry
%i = phi i64 [ %i.next, %for.body ], [ 0, %entry ]
%i0 = phi i32 [ %i3, %for.body ], [ 0, %entry ]
%i1 = getelementptr inbounds i32, ptr %b, i64 %i
%i2 = load i32, ptr %i1, align 8
store i32 %i2, ptr %a
%i3 = add i32 %i0, %i2
%i.next = add nuw nsw i64 %i, 1
%cond = icmp slt i64 %i.next, %n
br i1 %cond, label %for.body, label %for.end
for.end: ; preds = %for.body
%rdx.lcssa = phi i32 [ %i3, %for.body ]
ret i32 %rdx.lcssa
}