From 99ec36c684bd658b564d7db50463917a754daaab Mon Sep 17 00:00:00 2001
From: Tim Northover <tnorthover@apple.com>
Date: Tue, 1 Jul 2014 21:44:59 +0000
Subject: [PATCH] X86: delegate expanding atomic libcalls to generic code.

On targets without cmpxchg16b or cmpxchg8b, the borderline atomic
operations were slipping through the gaps.

X86AtomicExpand.cpp was delegating to ISelLowering. Generic
ISelLowering was delegating to X86ISelLowering and X86ISelLowering was
asserting. The correct behaviour is to expand to a libcall, preferably
in generic ISelLowering.

This can be achieved by X86ISelLowering deciding it doesn't want the
faff after all.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212134 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86ISelLowering.cpp        | 14 ++++++++
 test/CodeGen/X86/atomic-ops-ancient-64.ll | 43 +++++++++++++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 test/CodeGen/X86/atomic-ops-ancient-64.ll

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 10538ffc27f..fe8cebca942 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -16360,6 +16360,20 @@ void X86TargetLowering::ReplaceNodeResults(SDNode *N,
     Results.push_back(EFLAGS.getValue(1));
     return;
   }
+  case ISD::ATOMIC_SWAP:
+  case ISD::ATOMIC_LOAD_ADD:
+  case ISD::ATOMIC_LOAD_SUB:
+  case ISD::ATOMIC_LOAD_AND:
+  case ISD::ATOMIC_LOAD_OR:
+  case ISD::ATOMIC_LOAD_XOR:
+  case ISD::ATOMIC_LOAD_NAND:
+  case ISD::ATOMIC_LOAD_MIN:
+  case ISD::ATOMIC_LOAD_MAX:
+  case ISD::ATOMIC_LOAD_UMIN:
+  case ISD::ATOMIC_LOAD_UMAX:
+    // Delegate to generic TypeLegalization. Situations we can really handle
+    // should have already been dealt with by X86AtomicExpand.cpp.
+    break;
   case ISD::ATOMIC_LOAD: {
     ReplaceATOMIC_LOAD(N, Results, DAG);
     return;
diff --git a/test/CodeGen/X86/atomic-ops-ancient-64.ll b/test/CodeGen/X86/atomic-ops-ancient-64.ll
new file mode 100644
index 00000000000..18749b90287
--- /dev/null
+++ b/test/CodeGen/X86/atomic-ops-ancient-64.ll
@@ -0,0 +1,43 @@
+; RUN: llc -mtriple=i386-linux-gnu %s -o - | FileCheck %s
+
+define i64 @test_add(i64* %addr, i64 %inc) {
+; CHECK-LABEL: test_add:
+; CHECK: calll __sync_fetch_and_add_8
+  %old = atomicrmw add i64* %addr, i64 %inc seq_cst
+  ret i64 %old
+}
+
+define i64 @test_sub(i64* %addr, i64 %inc) {
+; CHECK-LABEL: test_sub:
+; CHECK: calll __sync_fetch_and_sub_8
+  %old = atomicrmw sub i64* %addr, i64 %inc seq_cst
+  ret i64 %old
+}
+
+define i64 @test_and(i64* %andr, i64 %inc) {
+; CHECK-LABEL: test_and:
+; CHECK: calll __sync_fetch_and_and_8
+  %old = atomicrmw and i64* %andr, i64 %inc seq_cst
+  ret i64 %old
+}
+
+define i64 @test_or(i64* %orr, i64 %inc) {
+; CHECK-LABEL: test_or:
+; CHECK: calll __sync_fetch_and_or_8
+  %old = atomicrmw or i64* %orr, i64 %inc seq_cst
+  ret i64 %old
+}
+
+define i64 @test_xor(i64* %xorr, i64 %inc) {
+; CHECK-LABEL: test_xor:
+; CHECK: calll __sync_fetch_and_xor_8
+  %old = atomicrmw xor i64* %xorr, i64 %inc seq_cst
+  ret i64 %old
+}
+
+define i64 @test_nand(i64* %nandr, i64 %inc) {
+; CHECK-LABEL: test_nand:
+; CHECK: calll __sync_fetch_and_nand_8
+  %old = atomicrmw nand i64* %nandr, i64 %inc seq_cst
+  ret i64 %old
+}