[SLP] avoid reduction transform on patterns that the backend can load-combine

I don't see an ideal solution to these 2 related, potentially large, perf regressions:
https://bugs.llvm.org/show_bug.cgi?id=42708
https://bugs.llvm.org/show_bug.cgi?id=43146

We decided that load combining was unsuitable for IR because it could obscure other
optimizations in IR. So we removed the LoadCombiner pass and deferred to the backend.
Therefore, preventing SLP from destroying load combine opportunities requires that it
recognizes patterns that could be combined later, but not do the optimization itself (
it's not a vector combine anyway, so it's probably out-of-scope for SLP).

Here, we add a scalar cost model adjustment with a conservative pattern match and cost
summation for a multi-instruction sequence that can probably be reduced later.
This should prevent SLP from creating a vector reduction unless that sequence is
extremely cheap.

In the x86 tests shown (and discussed in more detail in the bug reports), SDAG combining
will produce a single instruction on these tests like:

  movbe   rax, qword ptr [rdi]

or:

  mov     rax, qword ptr [rdi]

Not some (half) vector monstrosity as we currently do using SLP:

  vpmovzxbq       ymm0, dword ptr [rdi + 1] # ymm0 = mem[0],zero,zero,..
  vpsllvq ymm0, ymm0, ymmword ptr [rip + .LCPI0_0]
  movzx   eax, byte ptr [rdi]
  movzx   ecx, byte ptr [rdi + 5]
  shl     rcx, 40
  movzx   edx, byte ptr [rdi + 6]
  shl     rdx, 48
  or      rdx, rcx
  movzx   ecx, byte ptr [rdi + 7]
  shl     rcx, 56
  or      rcx, rdx
  or      rcx, rax
  vextracti128    xmm1, ymm0, 1
  vpor    xmm0, xmm0, xmm1
  vpshufd xmm1, xmm0, 78          # xmm1 = xmm0[2,3,0,1]
  vpor    xmm0, xmm0, xmm1
  vmovq   rax, xmm0
  or      rax, rcx
  vzeroupper
  ret

Differential Revision: https://reviews.llvm.org/D67841

llvm-svn: 373833

1 files changed, 104 insertions, 52 deletions

diff --git a/llvm/test/Transforms/SLPVectorizer/X86/bad-reduction.ll b/llvm/test/Transforms/SLPVectorizer/X86/bad-reduction.ll
index e3452e194db..c44a8524edf 100644
--- a/llvm/test/Transforms/SLPVectorizer/X86/bad-reduction.ll
+++ b/llvm/test/Transforms/SLPVectorizer/X86/bad-reduction.ll
@@ -15,31 +15,37 @@ define i64 @load_bswap(%v8i8* %p) {
 ; CHECK-NEXT:    [[G5:%.*]] = getelementptr inbounds [[V8I8]], %v8i8* [[P]], i64 0, i32 5
 ; CHECK-NEXT:    [[G6:%.*]] = getelementptr inbounds [[V8I8]], %v8i8* [[P]], i64 0, i32 6
 ; CHECK-NEXT:    [[G7:%.*]] = getelementptr inbounds [[V8I8]], %v8i8* [[P]], i64 0, i32 7
-; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[G0]] to <4 x i8>*
-; CHECK-NEXT:    [[TMP2:%.*]] = load <4 x i8>, <4 x i8>* [[TMP1]], align 1
+; CHECK-NEXT:    [[T0:%.*]] = load i8, i8* [[G0]]
+; CHECK-NEXT:    [[T1:%.*]] = load i8, i8* [[G1]]
+; CHECK-NEXT:    [[T2:%.*]] = load i8, i8* [[G2]]
+; CHECK-NEXT:    [[T3:%.*]] = load i8, i8* [[G3]]
 ; CHECK-NEXT:    [[T4:%.*]] = load i8, i8* [[G4]]
 ; CHECK-NEXT:    [[T5:%.*]] = load i8, i8* [[G5]]
 ; CHECK-NEXT:    [[T6:%.*]] = load i8, i8* [[G6]]
 ; CHECK-NEXT:    [[T7:%.*]] = load i8, i8* [[G7]]
-; CHECK-NEXT:    [[TMP3:%.*]] = zext <4 x i8> [[TMP2]] to <4 x i64>
+; CHECK-NEXT:    [[Z0:%.*]] = zext i8 [[T0]] to i64
+; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[T1]] to i64
+; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[T2]] to i64
+; CHECK-NEXT:    [[Z3:%.*]] = zext i8 [[T3]] to i64
 ; CHECK-NEXT:    [[Z4:%.*]] = zext i8 [[T4]] to i64
 ; CHECK-NEXT:    [[Z5:%.*]] = zext i8 [[T5]] to i64
 ; CHECK-NEXT:    [[Z6:%.*]] = zext i8 [[T6]] to i64
 ; CHECK-NEXT:    [[Z7:%.*]] = zext i8 [[T7]] to i64
-; CHECK-NEXT:    [[TMP4:%.*]] = shl nuw <4 x i64> [[TMP3]], <i64 56, i64 48, i64 40, i64 32>
+; CHECK-NEXT:    [[SH0:%.*]] = shl nuw i64 [[Z0]], 56
+; CHECK-NEXT:    [[SH1:%.*]] = shl nuw nsw i64 [[Z1]], 48
+; CHECK-NEXT:    [[SH2:%.*]] = shl nuw nsw i64 [[Z2]], 40
+; CHECK-NEXT:    [[SH3:%.*]] = shl nuw nsw i64 [[Z3]], 32
 ; CHECK-NEXT:    [[SH4:%.*]] = shl nuw nsw i64 [[Z4]], 24
 ; CHECK-NEXT:    [[SH5:%.*]] = shl nuw nsw i64 [[Z5]], 16
 ; CHECK-NEXT:    [[SH6:%.*]] = shl nuw nsw i64 [[Z6]], 8
-; CHECK-NEXT:    [[RDX_SHUF:%.*]] = shufflevector <4 x i64> [[TMP4]], <4 x i64> undef, <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX:%.*]] = or <4 x i64> [[TMP4]], [[RDX_SHUF]]
-; CHECK-NEXT:    [[RDX_SHUF1:%.*]] = shufflevector <4 x i64> [[BIN_RDX]], <4 x i64> undef, <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX2:%.*]] = or <4 x i64> [[BIN_RDX]], [[RDX_SHUF1]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <4 x i64> [[BIN_RDX2]], i32 0
-; CHECK-NEXT:    [[TMP6:%.*]] = or i64 [[TMP5]], [[SH4]]
-; CHECK-NEXT:    [[TMP7:%.*]] = or i64 [[TMP6]], [[SH5]]
-; CHECK-NEXT:    [[TMP8:%.*]] = or i64 [[TMP7]], [[SH6]]
-; CHECK-NEXT:    [[OP_EXTRA:%.*]] = or i64 [[TMP8]], [[Z7]]
-; CHECK-NEXT:    ret i64 [[OP_EXTRA]]
+; CHECK-NEXT:    [[OR01:%.*]] = or i64 [[SH0]], [[SH1]]
+; CHECK-NEXT:    [[OR012:%.*]] = or i64 [[OR01]], [[SH2]]
+; CHECK-NEXT:    [[OR0123:%.*]] = or i64 [[OR012]], [[SH3]]
+; CHECK-NEXT:    [[OR01234:%.*]] = or i64 [[OR0123]], [[SH4]]
+; CHECK-NEXT:    [[OR012345:%.*]] = or i64 [[OR01234]], [[SH5]]
+; CHECK-NEXT:    [[OR0123456:%.*]] = or i64 [[OR012345]], [[SH6]]
+; CHECK-NEXT:    [[OR01234567:%.*]] = or i64 [[OR0123456]], [[Z7]]
+; CHECK-NEXT:    ret i64 [[OR01234567]]
 ;
   %g0 = getelementptr inbounds %v8i8, %v8i8* %p, i64 0, i32 0
   %g1 = getelementptr inbounds %v8i8, %v8i8* %p, i64 0, i32 1
@@ -97,18 +103,38 @@ define i64 @load_bswap_nop_shift(%v8i8* %p) {
 ; CHECK-NEXT:    [[G5:%.*]] = getelementptr inbounds [[V8I8]], %v8i8* [[P]], i64 0, i32 5
 ; CHECK-NEXT:    [[G6:%.*]] = getelementptr inbounds [[V8I8]], %v8i8* [[P]], i64 0, i32 6
 ; CHECK-NEXT:    [[G7:%.*]] = getelementptr inbounds [[V8I8]], %v8i8* [[P]], i64 0, i32 7
-; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[G0]] to <8 x i8>*
-; CHECK-NEXT:    [[TMP2:%.*]] = load <8 x i8>, <8 x i8>* [[TMP1]], align 1
-; CHECK-NEXT:    [[TMP3:%.*]] = zext <8 x i8> [[TMP2]] to <8 x i64>
-; CHECK-NEXT:    [[TMP4:%.*]] = shl nuw <8 x i64> [[TMP3]], <i64 56, i64 48, i64 40, i64 32, i64 24, i64 16, i64 8, i64 0>
-; CHECK-NEXT:    [[RDX_SHUF:%.*]] = shufflevector <8 x i64> [[TMP4]], <8 x i64> undef, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX:%.*]] = or <8 x i64> [[TMP4]], [[RDX_SHUF]]
-; CHECK-NEXT:    [[RDX_SHUF1:%.*]] = shufflevector <8 x i64> [[BIN_RDX]], <8 x i64> undef, <8 x i32> <i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX2:%.*]] = or <8 x i64> [[BIN_RDX]], [[RDX_SHUF1]]
-; CHECK-NEXT:    [[RDX_SHUF3:%.*]] = shufflevector <8 x i64> [[BIN_RDX2]], <8 x i64> undef, <8 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX4:%.*]] = or <8 x i64> [[BIN_RDX2]], [[RDX_SHUF3]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <8 x i64> [[BIN_RDX4]], i32 0
-; CHECK-NEXT:    ret i64 [[TMP5]]
+; CHECK-NEXT:    [[T0:%.*]] = load i8, i8* [[G0]]
+; CHECK-NEXT:    [[T1:%.*]] = load i8, i8* [[G1]]
+; CHECK-NEXT:    [[T2:%.*]] = load i8, i8* [[G2]]
+; CHECK-NEXT:    [[T3:%.*]] = load i8, i8* [[G3]]
+; CHECK-NEXT:    [[T4:%.*]] = load i8, i8* [[G4]]
+; CHECK-NEXT:    [[T5:%.*]] = load i8, i8* [[G5]]
+; CHECK-NEXT:    [[T6:%.*]] = load i8, i8* [[G6]]
+; CHECK-NEXT:    [[T7:%.*]] = load i8, i8* [[G7]]
+; CHECK-NEXT:    [[Z0:%.*]] = zext i8 [[T0]] to i64
+; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[T1]] to i64
+; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[T2]] to i64
+; CHECK-NEXT:    [[Z3:%.*]] = zext i8 [[T3]] to i64
+; CHECK-NEXT:    [[Z4:%.*]] = zext i8 [[T4]] to i64
+; CHECK-NEXT:    [[Z5:%.*]] = zext i8 [[T5]] to i64
+; CHECK-NEXT:    [[Z6:%.*]] = zext i8 [[T6]] to i64
+; CHECK-NEXT:    [[Z7:%.*]] = zext i8 [[T7]] to i64
+; CHECK-NEXT:    [[SH0:%.*]] = shl nuw i64 [[Z0]], 56
+; CHECK-NEXT:    [[SH1:%.*]] = shl nuw nsw i64 [[Z1]], 48
+; CHECK-NEXT:    [[SH2:%.*]] = shl nuw nsw i64 [[Z2]], 40
+; CHECK-NEXT:    [[SH3:%.*]] = shl nuw nsw i64 [[Z3]], 32
+; CHECK-NEXT:    [[SH4:%.*]] = shl nuw nsw i64 [[Z4]], 24
+; CHECK-NEXT:    [[SH5:%.*]] = shl nuw nsw i64 [[Z5]], 16
+; CHECK-NEXT:    [[SH6:%.*]] = shl nuw nsw i64 [[Z6]], 8
+; CHECK-NEXT:    [[SH7:%.*]] = shl nuw nsw i64 [[Z7]], 0
+; CHECK-NEXT:    [[OR01:%.*]] = or i64 [[SH0]], [[SH1]]
+; CHECK-NEXT:    [[OR012:%.*]] = or i64 [[OR01]], [[SH2]]
+; CHECK-NEXT:    [[OR0123:%.*]] = or i64 [[OR012]], [[SH3]]
+; CHECK-NEXT:    [[OR01234:%.*]] = or i64 [[OR0123]], [[SH4]]
+; CHECK-NEXT:    [[OR012345:%.*]] = or i64 [[OR01234]], [[SH5]]
+; CHECK-NEXT:    [[OR0123456:%.*]] = or i64 [[OR012345]], [[SH6]]
+; CHECK-NEXT:    [[OR01234567:%.*]] = or i64 [[OR0123456]], [[SH7]]
+; CHECK-NEXT:    ret i64 [[OR01234567]]
 ;
   %g0 = getelementptr inbounds %v8i8, %v8i8* %p, i64 0, i32 0
   %g1 = getelementptr inbounds %v8i8, %v8i8* %p, i64 0, i32 1
@@ -168,30 +194,36 @@ define i64 @load64le(i8* %arg) {
 ; CHECK-NEXT:    [[G6:%.*]] = getelementptr inbounds i8, i8* [[ARG]], i64 6
 ; CHECK-NEXT:    [[G7:%.*]] = getelementptr inbounds i8, i8* [[ARG]], i64 7
 ; CHECK-NEXT:    [[LD0:%.*]] = load i8, i8* [[ARG]], align 1
-; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[G1]] to <4 x i8>*
-; CHECK-NEXT:    [[TMP2:%.*]] = load <4 x i8>, <4 x i8>* [[TMP1]], align 1
+; CHECK-NEXT:    [[LD1:%.*]] = load i8, i8* [[G1]], align 1
+; CHECK-NEXT:    [[LD2:%.*]] = load i8, i8* [[G2]], align 1
+; CHECK-NEXT:    [[LD3:%.*]] = load i8, i8* [[G3]], align 1
+; CHECK-NEXT:    [[LD4:%.*]] = load i8, i8* [[G4]], align 1
 ; CHECK-NEXT:    [[LD5:%.*]] = load i8, i8* [[G5]], align 1
 ; CHECK-NEXT:    [[LD6:%.*]] = load i8, i8* [[G6]], align 1
 ; CHECK-NEXT:    [[LD7:%.*]] = load i8, i8* [[G7]], align 1
 ; CHECK-NEXT:    [[Z0:%.*]] = zext i8 [[LD0]] to i64
-; CHECK-NEXT:    [[TMP3:%.*]] = zext <4 x i8> [[TMP2]] to <4 x i64>
+; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[LD1]] to i64
+; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[LD2]] to i64
+; CHECK-NEXT:    [[Z3:%.*]] = zext i8 [[LD3]] to i64
+; CHECK-NEXT:    [[Z4:%.*]] = zext i8 [[LD4]] to i64
 ; CHECK-NEXT:    [[Z5:%.*]] = zext i8 [[LD5]] to i64
 ; CHECK-NEXT:    [[Z6:%.*]] = zext i8 [[LD6]] to i64
 ; CHECK-NEXT:    [[Z7:%.*]] = zext i8 [[LD7]] to i64
-; CHECK-NEXT:    [[TMP4:%.*]] = shl nuw nsw <4 x i64> [[TMP3]], <i64 8, i64 16, i64 24, i64 32>
+; CHECK-NEXT:    [[S1:%.*]] = shl nuw nsw i64 [[Z1]], 8
+; CHECK-NEXT:    [[S2:%.*]] = shl nuw nsw i64 [[Z2]], 16
+; CHECK-NEXT:    [[S3:%.*]] = shl nuw nsw i64 [[Z3]], 24
+; CHECK-NEXT:    [[S4:%.*]] = shl nuw nsw i64 [[Z4]], 32
 ; CHECK-NEXT:    [[S5:%.*]] = shl nuw nsw i64 [[Z5]], 40
 ; CHECK-NEXT:    [[S6:%.*]] = shl nuw nsw i64 [[Z6]], 48
 ; CHECK-NEXT:    [[S7:%.*]] = shl nuw i64 [[Z7]], 56
-; CHECK-NEXT:    [[RDX_SHUF:%.*]] = shufflevector <4 x i64> [[TMP4]], <4 x i64> undef, <4 x i32> <i32 2, i32 3, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX:%.*]] = or <4 x i64> [[TMP4]], [[RDX_SHUF]]
-; CHECK-NEXT:    [[RDX_SHUF1:%.*]] = shufflevector <4 x i64> [[BIN_RDX]], <4 x i64> undef, <4 x i32> <i32 1, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX2:%.*]] = or <4 x i64> [[BIN_RDX]], [[RDX_SHUF1]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <4 x i64> [[BIN_RDX2]], i32 0
-; CHECK-NEXT:    [[TMP6:%.*]] = or i64 [[TMP5]], [[S5]]
-; CHECK-NEXT:    [[TMP7:%.*]] = or i64 [[TMP6]], [[S6]]
-; CHECK-NEXT:    [[TMP8:%.*]] = or i64 [[TMP7]], [[S7]]
-; CHECK-NEXT:    [[OP_EXTRA:%.*]] = or i64 [[TMP8]], [[Z0]]
-; CHECK-NEXT:    ret i64 [[OP_EXTRA]]
+; CHECK-NEXT:    [[O1:%.*]] = or i64 [[S1]], [[Z0]]
+; CHECK-NEXT:    [[O2:%.*]] = or i64 [[O1]], [[S2]]
+; CHECK-NEXT:    [[O3:%.*]] = or i64 [[O2]], [[S3]]
+; CHECK-NEXT:    [[O4:%.*]] = or i64 [[O3]], [[S4]]
+; CHECK-NEXT:    [[O5:%.*]] = or i64 [[O4]], [[S5]]
+; CHECK-NEXT:    [[O6:%.*]] = or i64 [[O5]], [[S6]]
+; CHECK-NEXT:    [[O7:%.*]] = or i64 [[O6]], [[S7]]
+; CHECK-NEXT:    ret i64 [[O7]]
 ;
   %g1 = getelementptr inbounds i8, i8* %arg, i64 1
   %g2 = getelementptr inbounds i8, i8* %arg, i64 2
@@ -247,18 +279,38 @@ define i64 @load64le_nop_shift(i8* %arg) {
 ; CHECK-NEXT:    [[G5:%.*]] = getelementptr inbounds i8, i8* [[ARG]], i64 5
 ; CHECK-NEXT:    [[G6:%.*]] = getelementptr inbounds i8, i8* [[ARG]], i64 6
 ; CHECK-NEXT:    [[G7:%.*]] = getelementptr inbounds i8, i8* [[ARG]], i64 7
-; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i8* [[ARG]] to <8 x i8>*
-; CHECK-NEXT:    [[TMP2:%.*]] = load <8 x i8>, <8 x i8>* [[TMP1]], align 1
-; CHECK-NEXT:    [[TMP3:%.*]] = zext <8 x i8> [[TMP2]] to <8 x i64>
-; CHECK-NEXT:    [[TMP4:%.*]] = shl nuw <8 x i64> [[TMP3]], <i64 0, i64 8, i64 16, i64 24, i64 32, i64 40, i64 48, i64 56>
-; CHECK-NEXT:    [[RDX_SHUF:%.*]] = shufflevector <8 x i64> [[TMP4]], <8 x i64> undef, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX:%.*]] = or <8 x i64> [[TMP4]], [[RDX_SHUF]]
-; CHECK-NEXT:    [[RDX_SHUF1:%.*]] = shufflevector <8 x i64> [[BIN_RDX]], <8 x i64> undef, <8 x i32> <i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX2:%.*]] = or <8 x i64> [[BIN_RDX]], [[RDX_SHUF1]]
-; CHECK-NEXT:    [[RDX_SHUF3:%.*]] = shufflevector <8 x i64> [[BIN_RDX2]], <8 x i64> undef, <8 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
-; CHECK-NEXT:    [[BIN_RDX4:%.*]] = or <8 x i64> [[BIN_RDX2]], [[RDX_SHUF3]]
-; CHECK-NEXT:    [[TMP5:%.*]] = extractelement <8 x i64> [[BIN_RDX4]], i32 0
-; CHECK-NEXT:    ret i64 [[TMP5]]
+; CHECK-NEXT:    [[LD0:%.*]] = load i8, i8* [[ARG]], align 1
+; CHECK-NEXT:    [[LD1:%.*]] = load i8, i8* [[G1]], align 1
+; CHECK-NEXT:    [[LD2:%.*]] = load i8, i8* [[G2]], align 1
+; CHECK-NEXT:    [[LD3:%.*]] = load i8, i8* [[G3]], align 1
+; CHECK-NEXT:    [[LD4:%.*]] = load i8, i8* [[G4]], align 1
+; CHECK-NEXT:    [[LD5:%.*]] = load i8, i8* [[G5]], align 1
+; CHECK-NEXT:    [[LD6:%.*]] = load i8, i8* [[G6]], align 1
+; CHECK-NEXT:    [[LD7:%.*]] = load i8, i8* [[G7]], align 1
+; CHECK-NEXT:    [[Z0:%.*]] = zext i8 [[LD0]] to i64
+; CHECK-NEXT:    [[Z1:%.*]] = zext i8 [[LD1]] to i64
+; CHECK-NEXT:    [[Z2:%.*]] = zext i8 [[LD2]] to i64
+; CHECK-NEXT:    [[Z3:%.*]] = zext i8 [[LD3]] to i64
+; CHECK-NEXT:    [[Z4:%.*]] = zext i8 [[LD4]] to i64
+; CHECK-NEXT:    [[Z5:%.*]] = zext i8 [[LD5]] to i64
+; CHECK-NEXT:    [[Z6:%.*]] = zext i8 [[LD6]] to i64
+; CHECK-NEXT:    [[Z7:%.*]] = zext i8 [[LD7]] to i64
+; CHECK-NEXT:    [[S0:%.*]] = shl nuw nsw i64 [[Z0]], 0
+; CHECK-NEXT:    [[S1:%.*]] = shl nuw nsw i64 [[Z1]], 8
+; CHECK-NEXT:    [[S2:%.*]] = shl nuw nsw i64 [[Z2]], 16
+; CHECK-NEXT:    [[S3:%.*]] = shl nuw nsw i64 [[Z3]], 24
+; CHECK-NEXT:    [[S4:%.*]] = shl nuw nsw i64 [[Z4]], 32
+; CHECK-NEXT:    [[S5:%.*]] = shl nuw nsw i64 [[Z5]], 40
+; CHECK-NEXT:    [[S6:%.*]] = shl nuw nsw i64 [[Z6]], 48
+; CHECK-NEXT:    [[S7:%.*]] = shl nuw i64 [[Z7]], 56
+; CHECK-NEXT:    [[O1:%.*]] = or i64 [[S1]], [[S0]]
+; CHECK-NEXT:    [[O2:%.*]] = or i64 [[O1]], [[S2]]
+; CHECK-NEXT:    [[O3:%.*]] = or i64 [[O2]], [[S3]]
+; CHECK-NEXT:    [[O4:%.*]] = or i64 [[O3]], [[S4]]
+; CHECK-NEXT:    [[O5:%.*]] = or i64 [[O4]], [[S5]]
+; CHECK-NEXT:    [[O6:%.*]] = or i64 [[O5]], [[S6]]
+; CHECK-NEXT:    [[O7:%.*]] = or i64 [[O6]], [[S7]]
+; CHECK-NEXT:    ret i64 [[O7]]
 ;
   %g1 = getelementptr inbounds i8, i8* %arg, i64 1
   %g2 = getelementptr inbounds i8, i8* %arg, i64 2