Reapply "[SLP] Initialize VectorizedValue when gathering"

The test case included in r279125 exposed existing undefined behavior in the
SLP vectorizer that it did not introduce. This patch reapplies the original
patch, but modifies the test case to avoid hitting the undefined behavior. This
allows us to close PR28330 while keeping the UBSan bot happy. The undefined
behavior the original test uncovered will be addressed in a follow-on patch.

Reference: https://llvm.org/bugs/show_bug.cgi?id=28330
llvm-svn: 279370

1 files changed, 87 insertions, 0 deletions

diff --git a/llvm/test/Transforms/SLPVectorizer/AArch64/gather-root.ll b/llvm/test/Transforms/SLPVectorizer/AArch64/gather-root.ll
new file mode 100644
index 00000000000..aefd015cce2
--- /dev/null
+++ b/llvm/test/Transforms/SLPVectorizer/AArch64/gather-root.ll
@@ -0,0 +1,87 @@
+; RUN: opt < %s -slp-vectorizer -S | FileCheck %s --check-prefix=DEFAULT
+; RUN: opt < %s -slp-schedule-budget=0 -slp-min-tree-size=0 -slp-threshold=-30 -slp-vectorizer -S | FileCheck %s --check-prefix=GATHER
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64--linux-gnu"
+
+@a = common global [80 x i8] zeroinitializer, align 16
+
+; DEFAULT-LABEL: @PR28330(
+; DEFAULT: %tmp17 = phi i32 [ %tmp34, %for.body ], [ 0, %entry ]
+; DEFAULT: %[[S0:.+]] = select <8 x i1> %1, <8 x i32> <i32 -720, i32 -720, i32 -720, i32 -720, i32 -720, i32 -720, i32 -720, i32 -720>, <8 x i32> <i32 -80, i32 -80, i32 -80, i32 -80, i32 -80, i32 -80, i32 -80, i32 -80>
+; DEFAULT: %[[R0:.+]] = shufflevector <8 x i32> %[[S0]], <8 x i32> undef, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 undef, i32 undef>
+; DEFAULT: %[[R1:.+]] = add <8 x i32> %[[S0]], %[[R0]]
+; DEFAULT: %[[R2:.+]] = shufflevector <8 x i32> %[[R1]], <8 x i32> undef, <8 x i32> <i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; DEFAULT: %[[R3:.+]] = add <8 x i32> %[[R1]], %[[R2]]
+; DEFAULT: %[[R4:.+]] = shufflevector <8 x i32> %[[R3]], <8 x i32> undef, <8 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; DEFAULT: %[[R5:.+]] = add <8 x i32> %[[R3]], %[[R4]]
+; DEFAULT: %[[R6:.+]] = extractelement <8 x i32> %[[R5]], i32 0
+; DEFAULT: %tmp34 = add i32 %[[R6]], %tmp17
+;
+; GATHER-LABEL: @PR28330(
+; GATHER: %tmp17 = phi i32 [ %tmp34, %for.body ], [ 0, %entry ]
+; GATHER: %tmp19 = select i1 %tmp1, i32 -720, i32 -80
+; GATHER: %tmp21 = select i1 %tmp3, i32 -720, i32 -80
+; GATHER: %tmp23 = select i1 %tmp5, i32 -720, i32 -80
+; GATHER: %tmp25 = select i1 %tmp7, i32 -720, i32 -80
+; GATHER: %tmp27 = select i1 %tmp9, i32 -720, i32 -80
+; GATHER: %tmp29 = select i1 %tmp11, i32 -720, i32 -80
+; GATHER: %tmp31 = select i1 %tmp13, i32 -720, i32 -80
+; GATHER: %tmp33 = select i1 %tmp15, i32 -720, i32 -80
+; GATHER: %[[I0:.+]] = insertelement <8 x i32> undef, i32 %tmp19, i32 0
+; GATHER: %[[I1:.+]] = insertelement <8 x i32> %[[I0]], i32 %tmp21, i32 1
+; GATHER: %[[I2:.+]] = insertelement <8 x i32> %[[I1]], i32 %tmp23, i32 2
+; GATHER: %[[I3:.+]] = insertelement <8 x i32> %[[I2]], i32 %tmp25, i32 3
+; GATHER: %[[I4:.+]] = insertelement <8 x i32> %[[I3]], i32 %tmp27, i32 4
+; GATHER: %[[I5:.+]] = insertelement <8 x i32> %[[I4]], i32 %tmp29, i32 5
+; GATHER: %[[I6:.+]] = insertelement <8 x i32> %[[I5]], i32 %tmp31, i32 6
+; GATHER: %[[I7:.+]] = insertelement <8 x i32> %[[I6]], i32 %tmp33, i32 7
+; GATHER: %[[R0:.+]] = shufflevector <8 x i32> %[[I7]], <8 x i32> undef, <8 x i32> <i32 4, i32 5, i32 6, i32 7, i32 undef, i32 undef, i32 undef, i32 undef>
+; GATHER: %[[R1:.+]] = add <8 x i32> %[[I7]], %[[R0]]
+; GATHER: %[[R2:.+]] = shufflevector <8 x i32> %[[R1]], <8 x i32> undef, <8 x i32> <i32 2, i32 3, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; GATHER: %[[R3:.+]] = add <8 x i32> %[[R1]], %[[R2]]
+; GATHER: %[[R4:.+]] = shufflevector <8 x i32> %[[R3]], <8 x i32> undef, <8 x i32> <i32 1, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef, i32 undef>
+; GATHER: %[[R5:.+]] = add <8 x i32> %[[R3]], %[[R4]]
+; GATHER: %[[R6:.+]] = extractelement <8 x i32> %[[R5]], i32 0
+; GATHER: %tmp34 = add i32 %[[R6]], %tmp17
+
+define void @PR28330(i32 %n) {
+entry:
+  %tmp0 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 1), align 1
+  %tmp1 = icmp eq i8 %tmp0, 0
+  %tmp2 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 2), align 2
+  %tmp3 = icmp eq i8 %tmp2, 0
+  %tmp4 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 3), align 1
+  %tmp5 = icmp eq i8 %tmp4, 0
+  %tmp6 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 4), align 4
+  %tmp7 = icmp eq i8 %tmp6, 0
+  %tmp8 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 5), align 1
+  %tmp9 = icmp eq i8 %tmp8, 0
+  %tmp10 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 6), align 2
+  %tmp11 = icmp eq i8 %tmp10, 0
+  %tmp12 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 7), align 1
+  %tmp13 = icmp eq i8 %tmp12, 0
+  %tmp14 = load i8, i8* getelementptr inbounds ([80 x i8], [80 x i8]* @a, i64 0, i64 8), align 8
+  %tmp15 = icmp eq i8 %tmp14, 0
+  br label %for.body
+
+for.body:
+  %tmp17 = phi i32 [ %tmp34, %for.body ], [ 0, %entry ]
+  %tmp19 = select i1 %tmp1, i32 -720, i32 -80
+  %tmp20 = add i32 %tmp17, %tmp19
+  %tmp21 = select i1 %tmp3, i32 -720, i32 -80
+  %tmp22 = add i32 %tmp20, %tmp21
+  %tmp23 = select i1 %tmp5, i32 -720, i32 -80
+  %tmp24 = add i32 %tmp22, %tmp23
+  %tmp25 = select i1 %tmp7, i32 -720, i32 -80
+  %tmp26 = add i32 %tmp24, %tmp25
+  %tmp27 = select i1 %tmp9, i32 -720, i32 -80
+  %tmp28 = add i32 %tmp26, %tmp27
+  %tmp29 = select i1 %tmp11, i32 -720, i32 -80
+  %tmp30 = add i32 %tmp28, %tmp29
+  %tmp31 = select i1 %tmp13, i32 -720, i32 -80
+  %tmp32 = add i32 %tmp30, %tmp31
+  %tmp33 = select i1 %tmp15, i32 -720, i32 -80
+  %tmp34 = add i32 %tmp32, %tmp33
+  br label %for.body
+}