From b6db95f42b7c3b58f980e387d20ddb3e16bffd56 Mon Sep 17 00:00:00 2001
From: Nadav Rotem <nrotem@apple.com>
Date: Sun, 13 Jan 2013 07:56:29 +0000
Subject: [PATCH] Fix PR14547. Handle induction variables of small sizes
 smaller than i32 (i8 and i16).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172348 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Vectorize/LoopVectorize.cpp    |  3 +++
 test/Transforms/LoopVectorize/i8-induction.ll | 35 +++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)
 create mode 100644 test/Transforms/LoopVectorize/i8-induction.ll

diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 4bb8c436564..464ed97506f 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -1033,11 +1033,14 @@ InnerLoopVectorizer::createEmptyLoop(LoopVectorizationLegality *Legal) {
 
   // We may need to extend the index in case there is a type mismatch.
   // We know that the count starts at zero and does not overflow.
+  unsigned IdxTyBW = IdxTy->getScalarSizeInBits();
   if (Count->getType() != IdxTy) {
     // The exit count can be of pointer type. Convert it to the correct
     // integer type.
     if (ExitCount->getType()->isPointerTy())
       Count = CastInst::CreatePointerCast(Count, IdxTy, "ptrcnt.to.int", Loc);
+    else if (IdxTyBW < Count->getType()->getScalarSizeInBits())
+      Count = CastInst::CreateTruncOrBitCast(Count, IdxTy, "tr.cnt", Loc);
     else
       Count = CastInst::CreateZExtOrBitCast(Count, IdxTy, "zext.cnt", Loc);
   }
diff --git a/test/Transforms/LoopVectorize/i8-induction.ll b/test/Transforms/LoopVectorize/i8-induction.ll
new file mode 100644
index 00000000000..7759b7085a1
--- /dev/null
+++ b/test/Transforms/LoopVectorize/i8-induction.ll
@@ -0,0 +1,35 @@
+; RUN: opt < %s  -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -dce -instcombine -S
+
+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"
+target triple = "x86_64-apple-macosx10.8.0"
+
+@a = common global i8 0, align 1
+@b = common global i8 0, align 1
+
+define void @f() nounwind uwtable ssp {
+scalar.ph:
+  store i8 0, i8* inttoptr (i64 1 to i8*), align 1, !tbaa !0
+  %0 = load i8* @a, align 1, !tbaa !0
+  br label %for.body
+
+for.body:
+  %mul16 = phi i8 [ 0, %scalar.ph ], [ %mul, %for.body ]              ; <------- i8 induction var.
+  %c.015 = phi i8 [ undef, %scalar.ph ], [ %conv8, %for.body ]
+  %conv2 = sext i8 %c.015 to i32
+  %tobool = icmp ne i8 %c.015, 0
+  %.sink = select i1 %tobool, i8 %c.015, i8 %0
+  %mul = mul i8 %mul16, %.sink
+  %add = add nsw i32 %conv2, 1
+  %conv8 = trunc i32 %add to i8
+  %sext = shl i32 %add, 24
+  %phitmp14 = icmp slt i32 %sext, 268435456
+  br i1 %phitmp14, label %for.body, label %for.end
+
+for.end:                                          ; preds = %for.body
+  store i8 %mul, i8* @b, align 1, !tbaa !0
+  ret void
+}
+
+!0 = metadata !{metadata !"omnipotent char", metadata !1}
+!1 = metadata !{metadata !"Simple C/C++ TBAA"}
+
-- 
2.11.0