From 436c90619c16bd8a7466b0105fa087c7147373c2 Mon Sep 17 00:00:00 2001
From: Michael Kruse <llvm@meinersbur.de>
Date: Fri, 8 Apr 2016 16:20:08 +0000
Subject: [PATCH] [ScopInfo] Fix check for element size mismatch.

The way to get the elements size with getPrimitiveSizeInBits() is not
the same as used in other parts of Polly which should use
DataLayout::getTypeAllocSize(). Its use only queries the size of the
pointer and getPrimitiveSizeInBits returns 0 for types that require a
DataLayout object such as pointers.

Together with r265379, this should fix PR27195.

llvm-svn: 265795
---
 polly/lib/Analysis/ScopInfo.cpp                 |  4 +-
 polly/test/ScopInfo/multidim_gep_pointercast.ll | 56 +++++++++++++++++++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)
 create mode 100644 polly/test/ScopInfo/multidim_gep_pointercast.ll

diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index 24cd721..23b82c5 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -3992,7 +3992,9 @@ bool ScopInfo::buildAccessMultiDimFixed(
     auto *Src = BitCast->getOperand(0);
     auto *SrcTy = Src->getType();
     auto *DstTy = BitCast->getType();
-    if (SrcTy->getPrimitiveSizeInBits() == DstTy->getPrimitiveSizeInBits())
+    if (SrcTy->isPointerTy() && DstTy->isPointerTy() &&
+        DL->getTypeAllocSize(SrcTy->getPointerElementType()) ==
+            DL->getTypeAllocSize(DstTy->getPointerElementType()))
       Address = Src;
   }
 
diff --git a/polly/test/ScopInfo/multidim_gep_pointercast.ll b/polly/test/ScopInfo/multidim_gep_pointercast.ll
new file mode 100644
index 0000000..3091767
--- /dev/null
+++ b/polly/test/ScopInfo/multidim_gep_pointercast.ll
@@ -0,0 +1,56 @@
+; RUN: opt %loadPolly -polly-scops -analyze < %s | FileCheck %s
+;
+; The load access to A has a pointer-bitcast to another elements size before the
+; GetElementPtr. Verify that we do not the GEP delinearization because it
+; mismatches with the size of the loaded element type.
+;
+;    void f(short A[][4], int N, int P) {
+;      short(*B)[4] = &A[P][0];
+;      for (int i = 0; i < N; i++)
+;        *((<4 x short> *)&A[7 * i][0]) = *((<4 x short>)&B[7 * i][0]);
+;    }
+;
+define void @f([4 x i16]* %A, i32 %N, i32 %P) {
+entry:
+  %arrayidx1 = getelementptr inbounds [4 x i16], [4 x i16]* %A, i32 %P, i64 0
+  %tmp = bitcast i16* %arrayidx1 to [4 x i16]*
+  br label %for.cond
+
+for.cond:
+  %indvars.iv = phi i32 [ %indvars.iv.next, %for.inc ], [ 0, %entry ]
+  %cmp = icmp slt i32 %indvars.iv, %N
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:
+  %mul = mul nsw i32 %indvars.iv, 7
+  %arrayidx4 = getelementptr inbounds [4 x i16], [4 x i16]* %tmp, i32 %mul, i64 0
+  %bc4 = bitcast i16* %arrayidx4 to <4 x i16>*
+  %tmp3 = load <4 x i16>, <4 x i16>* %bc4
+  %arrayidx8 = getelementptr inbounds [4 x i16], [4 x i16]* %A, i32 %mul, i64 0
+  %bc8 = bitcast i16* %arrayidx8 to <4 x i16>*
+  store <4 x i16> %tmp3, <4 x i16>* %bc8
+  br label %for.inc
+
+for.inc:
+  %indvars.iv.next = add nuw nsw i32 %indvars.iv, 1
+  br label %for.cond
+
+for.end:
+  ret void
+}
+
+
+; CHECK:      Arrays {
+; CHECK-NEXT:     <4 x i16> MemRef_A[*]; // Element size 8
+; CHECK-NEXT: }
+; CHECK:      Statements {
+; CHECK-NEXT:     Stmt_for_body
+; CHECK-NEXT:         Domain :=
+; CHECK-NEXT:             [N, P] -> { Stmt_for_body[i0] : 0 <= i0 < N };
+; CHECK-NEXT:         Schedule :=
+; CHECK-NEXT:             [N, P] -> { Stmt_for_body[i0] -> [i0] };
+; CHECK-NEXT:         ReadAccess :=    [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT:             [N, P] -> { Stmt_for_body[i0] -> MemRef_A[P + 7i0] };
+; CHECK-NEXT:         MustWriteAccess :=    [Reduction Type: NONE] [Scalar: 0]
+; CHECK-NEXT:             [N, P] -> { Stmt_for_body[i0] -> MemRef_A[7i0] };
+; CHECK-NEXT: }
-- 
2.7.4