From f2c8771612905e590453b2f5f3e851d184cf7509 Mon Sep 17 00:00:00 2001
From: Suyog Sarda <quic_ssarda@quicinc.com>
Date: Sat, 21 Sep 2019 18:16:37 +0000
Subject: Merging r372480:

------------------------------------------------------------------------
r372480 | ssarda | 2019-09-21 11:16:37 -0700 (Sat, 21 Sep 2019) | 9 lines

SROA: Check Total Bits of vector type

While Promoting alloca instruction of Vector Type,
Check total size in bits of its slices too.
If they don't match, don't promote the alloca instruction.

Bug : https://bugs.llvm.org/show_bug.cgi?id=42585

------------------------------------------------------------------------
---
 llvm/lib/Transforms/Scalar/SROA.cpp                |  8 ++++++++
 .../SROA/vector-promotion-different-size.ll        | 24 ++++++++++++++++++++++
 2 files changed, 32 insertions(+)
 create mode 100644 llvm/test/Transforms/SROA/vector-promotion-different-size.ll

diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
index 33f90d0..bd4c21d 100644
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -1888,6 +1888,14 @@ static VectorType *isVectorPromotionViable(Partition &P, const DataLayout &DL) {
   bool HaveCommonEltTy = true;
   auto CheckCandidateType = [&](Type *Ty) {
     if (auto *VTy = dyn_cast<VectorType>(Ty)) {
+      // Return if bitcast to vectors is different for total size in bits.
+      if (!CandidateTys.empty()) {
+        VectorType *V = CandidateTys[0];
+        if (DL.getTypeSizeInBits(VTy) != DL.getTypeSizeInBits(V)) {
+          CandidateTys.clear();
+          return;
+        }
+      }
       CandidateTys.push_back(VTy);
       if (!CommonEltTy)
         CommonEltTy = VTy->getElementType();
diff --git a/llvm/test/Transforms/SROA/vector-promotion-different-size.ll b/llvm/test/Transforms/SROA/vector-promotion-different-size.ll
new file mode 100644
index 0000000..56e1f1f
--- /dev/null
+++ b/llvm/test/Transforms/SROA/vector-promotion-different-size.ll
@@ -0,0 +1,24 @@
+; RUN: opt < %s -sroa -S | FileCheck %s
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-n8:16:32:64"
+
+define <4 x i1> @vector_bitcast() {
+  ; CHECK-LABEL: @vector_bitcast
+  ; CHECK: alloca i1
+
+    %a = alloca <3 x i1>
+    store <3 x i1> <i1 1,i1 0,i1 1>, <3 x i1>* %a
+    %cast = bitcast <3 x i1>* %a to <4 x i1>*
+    %vec = load <4 x i1>, <4 x i1>* %cast
+    ret <4 x i1> %vec
+}
+
+define void @vector_bitcast_2() {
+  ; CHECK-LABEL: @vector_bitcast_2
+  ; CHECK: alloca <32 x i16>
+
+    %"sum$1.host2" = alloca <32 x i16>
+    store <32 x i16> undef, <32 x i16>* %"sum$1.host2"
+    %bc = bitcast <32 x i16>* %"sum$1.host2" to <64 x i16>*
+    %bcl = load <64 x i16>, <64 x i16>* %bc
+    ret void
+}
-- 
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