From: Dan Gohman <gohman@apple.com>
Date: Thu, 21 Jul 2011 23:30:09 +0000 (+0000)
Subject: Fix MergeInVectorType to check for vector types with the same alloc
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=856e13ddace4174ad1b07f65ebb18b2fd835ed57;p=oota-llvm.git

Fix MergeInVectorType to check for vector types with the same alloc
size but different element types, so that it filters out the cases
that CreateShuffleVectorCast doesn't handle. This fixes rdar://9786827.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135721 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index fbf309292d8..b3d7ef6ec10 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -425,6 +425,12 @@ bool ConvertToScalarInfo::MergeInVectorType(VectorType *VInTy,
   Type *ElementTy = VectorTy->getElementType();
   Type *InElementTy = VInTy->getElementType();
 
+  // If they're the same alloc size, we'll be attempting to convert between
+  // them with a vector shuffle, which requires the element types to match.
+  if (TD.getTypeAllocSize(VectorTy) == TD.getTypeAllocSize(VInTy) &&
+      ElementTy != InElementTy)
+    return false;
+
   // Do not allow mixed integer and floating-point accesses from vectors of
   // different sizes.
   if (ElementTy->isFloatingPointTy() != InElementTy->isFloatingPointTy())
diff --git a/test/Transforms/ScalarRepl/vectors-with-mismatched-elements.ll b/test/Transforms/ScalarRepl/vectors-with-mismatched-elements.ll
new file mode 100644
index 00000000000..c3fbdf5f863
--- /dev/null
+++ b/test/Transforms/ScalarRepl/vectors-with-mismatched-elements.ll
@@ -0,0 +1,27 @@
+; RUN: opt -scalarrepl -S < %s | FileCheck %s
+; rdar://9786827
+
+; SROA should be able to handle the mixed types and eliminate the allocas here.
+
+; TODO: Currently it does this by falling back to integer "bags of bits".
+; With enough cleverness, it should be possible to convert between <3 x i32>
+; and <2 x i64> by using a combination of a bitcast and a shuffle.
+
+; CHECK: {
+; CHECK-NOT: alloca
+; CHECK: }
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n8:16:32"
+target triple = "i386-apple-darwin11.0.0"
+
+define <2 x i64> @foo() nounwind {
+entry:
+  %retval = alloca <3 x i32>, align 16
+  %z = alloca <4 x i32>, align 16
+  %tmp = load <4 x i32>* %z
+  %tmp1 = shufflevector <4 x i32> %tmp, <4 x i32> undef, <3 x i32> <i32 0, i32 1, i32 2>
+  store <3 x i32> %tmp1, <3 x i32>* %retval
+  %0 = bitcast <3 x i32>* %retval to <2 x i64>*
+  %1 = load <2 x i64>* %0, align 1
+  ret <2 x i64> %1
+}