From 36713c2c0a9e4aeebe4cae4ef5efbc13d4103850 Mon Sep 17 00:00:00 2001
From: Andrea Di Biagio <Andrea_DiBiagio@sn.scee.net>
Date: Mon, 13 Jan 2014 16:51:00 +0000
Subject: [PATCH] [AArch64] Fix assertion failure caused by an invalid
 comparison between APInt values.

APInt only knows how to compare values with the same BitWidth and asserts
in all other cases.

With this fix, function PerformORCombine does not use the APInt equality
operator if the APInt values returned by 'isConstantSplat' differ in BitWidth.
In that case they are different and no comparison is needed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@199119 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/AArch64/AArch64ISelLowering.cpp |  5 ++--
 test/CodeGen/AArch64/neon-or-combine.ll    | 29 ++++++++++++++++++++++
 2 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 test/CodeGen/AArch64/neon-or-combine.ll

diff --git a/lib/Target/AArch64/AArch64ISelLowering.cpp b/lib/Target/AArch64/AArch64ISelLowering.cpp
index ce9ce3aeb5f..317a41a05f4 100644
--- a/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -3476,8 +3476,9 @@ static SDValue PerformORCombine(SDNode *N,
       BuildVectorSDNode *BVN1 = dyn_cast<BuildVectorSDNode>(N1->getOperand(1));
       APInt SplatBits1;
       if (BVN1 && BVN1->isConstantSplat(SplatBits1, SplatUndef, SplatBitSize,
-                                        HasAnyUndefs) &&
-          !HasAnyUndefs && SplatBits0 == ~SplatBits1) {
+                                        HasAnyUndefs) && !HasAnyUndefs &&
+          SplatBits0.getBitWidth() == SplatBits1.getBitWidth() &&
+          SplatBits0 == ~SplatBits1) {
 
         return DAG.getNode(ISD::VSELECT, DL, VT, N0->getOperand(1),
                            N0->getOperand(0), N1->getOperand(0));
diff --git a/test/CodeGen/AArch64/neon-or-combine.ll b/test/CodeGen/AArch64/neon-or-combine.ll
new file mode 100644
index 00000000000..260f6935dde
--- /dev/null
+++ b/test/CodeGen/AArch64/neon-or-combine.ll
@@ -0,0 +1,29 @@
+; RUN: llc < %s -mtriple=aarch64-none-linux-gnu -mattr=+neon | FileCheck %s
+
+; Check that the DAGCombiner does not crash with an assertion failure
+; when performing a target specific combine to simplify a 'or' dag node
+; according to the following rule:
+;   (or (and B, A), (and C, ~A)) => (VBSL A, B, C)
+; The assertion failure was caused by an invalid comparison between APInt
+; values with different 'BitWidth'.
+
+define <8 x i8> @test1(<8 x i8> %a, <8 x i8> %b)  {
+  %tmp1 = and <8 x i8> %a, < i8 -1, i8 -1, i8 0, i8 0, i8 -1, i8 -1, i8 0, i8 0 >
+  %tmp2 = and <8 x i8> %b, < i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0 >
+  %tmp3 = or <8 x i8> %tmp1, %tmp2
+  ret <8 x i8> %tmp3
+}
+
+; CHECK-LABEL: test1
+; CHECK: ret
+
+define <16 x i8> @test2(<16 x i8> %a, <16 x i8> %b) {
+  %tmp1 = and <16 x i8> %a, < i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1, i8 -1 >
+  %tmp2 = and <16 x i8> %b, < i8 -1, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0, i8 0 >
+  %tmp3 = or <16 x i8> %tmp1, %tmp2
+  ret <16 x i8> %tmp3
+}
+
+; CHECK-LABEL: test2
+; CHECK: ret
+
-- 
2.34.1