From ae81c293521887284aca35059070bc688bcae771 Mon Sep 17 00:00:00 2001
From: Matthias Braun <matze@braunis.de>
Date: Thu, 24 Mar 2016 21:41:38 +0000
Subject: [PATCH] LiveInterval: Fix Distribute() failing on liveranges with
 unused VNInfos

This fixes http://llvm.org/PR26991

llvm-svn: 264345
---
 llvm/lib/CodeGen/LiveInterval.cpp                | 21 ++++++----
 llvm/test/CodeGen/AMDGPU/coalescer_distribute.ll | 53 ++++++++++++++++++++++++
 2 files changed, 66 insertions(+), 8 deletions(-)
 create mode 100644 llvm/test/CodeGen/AMDGPU/coalescer_distribute.ll

diff --git a/llvm/lib/CodeGen/LiveInterval.cpp b/llvm/lib/CodeGen/LiveInterval.cpp
index ab78072..171d18a 100644
--- a/llvm/lib/CodeGen/LiveInterval.cpp
+++ b/llvm/lib/CodeGen/LiveInterval.cpp
@@ -1483,15 +1483,20 @@ void ConnectedVNInfoEqClasses::Distribute(LiveInterval &LI, LiveInterval *LIV[],
       SubRanges.resize(NumComponents-1, nullptr);
       for (unsigned I = 0; I < NumValNos; ++I) {
         const VNInfo &VNI = *SR.valnos[I];
-        const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
-        assert(MainRangeVNI != nullptr
-               && "SubRange def must have corresponding main range def");
-        unsigned ComponentNum = getEqClass(MainRangeVNI);
-        VNIMapping.push_back(ComponentNum);
-        if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
-          SubRanges[ComponentNum-1]
-            = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
+        unsigned ComponentNum;
+        if (VNI.isUnused()) {
+          ComponentNum = 0;
+        } else {
+          const VNInfo *MainRangeVNI = LI.getVNInfoAt(VNI.def);
+          assert(MainRangeVNI != nullptr
+                 && "SubRange def must have corresponding main range def");
+          ComponentNum = getEqClass(MainRangeVNI);
+          if (ComponentNum > 0 && SubRanges[ComponentNum-1] == nullptr) {
+            SubRanges[ComponentNum-1]
+              = LIV[ComponentNum-1]->createSubRange(Allocator, SR.LaneMask);
+          }
         }
+        VNIMapping.push_back(ComponentNum);
       }
       DistributeRange(SR, SubRanges.data(), VNIMapping);
     }
diff --git a/llvm/test/CodeGen/AMDGPU/coalescer_distribute.ll b/llvm/test/CodeGen/AMDGPU/coalescer_distribute.ll
new file mode 100644
index 0000000..7ca2612
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/coalescer_distribute.ll
@@ -0,0 +1,53 @@
+; RUN: llc -o /dev/null %s
+; This testcase produces a situation with unused value numbers in subregister
+; liveranges that get distributed by ConnectedVNInfoEqClasses.
+target triple = "amdgcn--"
+
+define spir_kernel void @hoge() {
+bb:
+  %tmp = tail call i32 @llvm.r600.read.tidig.x()
+  br i1 undef, label %bb2, label %bb23
+
+bb2:
+  br i1 undef, label %bb6, label %bb8
+
+bb6:
+  %tmp7 = or i64 undef, undef
+  br label %bb8
+
+bb8:
+  %tmp9 = phi i64 [ %tmp7, %bb6 ], [ undef, %bb2 ]
+  %tmp10 = icmp eq i32 %tmp, 0
+  br i1 %tmp10, label %bb11, label %bb23
+
+bb11:
+  br i1 undef, label %bb20, label %bb17
+
+bb17:
+  br label %bb20
+
+bb20:
+  %tmp21 = phi i64 [ undef, %bb17 ], [ %tmp9, %bb11 ]
+  %tmp22 = trunc i64 %tmp21 to i32
+  br label %bb23
+
+bb23:
+  %tmp24 = phi i32 [ %tmp22, %bb20 ], [ undef, %bb8 ], [ undef, %bb ]
+  br label %bb25
+
+bb25:
+  %tmp26 = phi i32 [ %tmp24, %bb23 ], [ undef, %bb25 ]
+  br i1 undef, label %bb25, label %bb30
+
+bb30:
+  br i1 undef, label %bb32, label %bb34
+
+bb32:
+  %tmp33 = zext i32 %tmp26 to i64
+  br label %bb34
+
+bb34:
+  ret void
+}
+
+declare i32 @llvm.r600.read.tidig.x()
-- 
2.7.4