From: Tim Northover <tnorthover@apple.com>
Date: Thu, 17 Aug 2017 23:14:01 +0000 (+0000)
Subject: GlobalISel (AArch64): fix ABI at border between GPRs and SP.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e8fd20964798ca6d46d2729dd3a789707a6416da;p=llvm

GlobalISel (AArch64): fix ABI at border between GPRs and SP.

If a struct would end up half in GPRs and half on SP the ABI says it should
actually go entirely on the stack. We were getting this wrong in GlobalISel
before, causing compatibility issues.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@311137 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/AArch64/AArch64CallLowering.cpp b/lib/Target/AArch64/AArch64CallLowering.cpp
index fc09763ed38..a0ef3262483 100644
--- a/lib/Target/AArch64/AArch64CallLowering.cpp
+++ b/lib/Target/AArch64/AArch64CallLowering.cpp
@@ -188,12 +188,16 @@ void AArch64CallLowering::splitToValueTypes(
   }
 
   unsigned FirstRegIdx = SplitArgs.size();
+  bool AlreadySplit = false;
   for (auto SplitVT : SplitVTs) {
-    // FIXME: set split flags if they're actually used (e.g. i128 on AAPCS).
     Type *SplitTy = SplitVT.getTypeForEVT(Ctx);
     SplitArgs.push_back(
         ArgInfo{MRI.createGenericVirtualRegister(getLLTForType(*SplitTy, DL)),
                 SplitTy, OrigArg.Flags, OrigArg.IsFixed});
+    if (!AlreadySplit) {
+      SplitArgs.back().Flags.setSplit();
+      AlreadySplit = true;
+    }
   }
 
   for (unsigned i = 0; i < Offsets.size(); ++i)
diff --git a/test/CodeGen/AArch64/GlobalISel/call-translator.ll b/test/CodeGen/AArch64/GlobalISel/call-translator.ll
index 1cc196be359..b5d85055f23 100644
--- a/test/CodeGen/AArch64/GlobalISel/call-translator.ll
+++ b/test/CodeGen/AArch64/GlobalISel/call-translator.ll
@@ -215,3 +215,42 @@ define void @test_call_stack() {
 define void @test_mem_i1([8 x i64], i1 %in) {
   ret void
 }
+
+; CHECK-LABEL: name: test_split_struct
+; CHECK: [[STRUCT:%[0-9]+]](s128) = G_LOAD {{.*}}(p0)
+; CHECK: [[LO:%[0-9]+]](s64) = G_EXTRACT [[STRUCT]](s128), 0
+; CHECK: [[HI:%[0-9]+]](s64) = G_EXTRACT [[STRUCT]](s128), 64
+
+; CHECK: [[SP:%[0-9]+]](p0) = COPY %sp
+; CHECK: [[OFF:%[0-9]+]](s64) = G_CONSTANT i64 0
+; CHECK: [[ADDR:%[0-9]+]](p0) = G_GEP [[SP]], [[OFF]]
+; CHECK: G_STORE [[LO]](s64), [[ADDR]](p0) :: (store 8 into stack, align 0)
+
+; CHECK: [[SP:%[0-9]+]](p0) = COPY %sp
+; CHECK: [[OFF:%[0-9]+]](s64) = G_CONSTANT i64 8
+; CHECK: [[ADDR:%[0-9]+]](p0) = G_GEP [[SP]], [[OFF]]
+; CHECK: G_STORE [[HI]](s64), [[ADDR]](p0) :: (store 8 into stack + 8, align 0)
+define void @test_split_struct([2 x i64]* %ptr) {
+  %struct = load [2 x i64], [2 x i64]* %ptr
+  call void @take_split_struct([2 x i64]* null, i64 1, i64 2, i64 3,
+                               i64 4, i64 5, i64 6,
+                               [2 x i64] %struct)
+  ret void
+}
+
+; CHECK-LABEL: name: take_split_struct
+; CHECK: fixedStack:
+; CHECK-DAG:   - { id: [[LO_FRAME:[0-9]+]], type: default, offset: 0, size: 8
+; CHECK-DAG:   - { id: [[HI_FRAME:[0-9]+]], type: default, offset: 8, size: 8
+
+; CHECK: [[LOPTR:%[0-9]+]](p0) = G_FRAME_INDEX %fixed-stack.[[LO_FRAME]]
+; CHECK: [[LO:%[0-9]+]](s64) = G_LOAD [[LOPTR]](p0) :: (invariant load 8 from %fixed-stack.[[LO_FRAME]], align 0)
+
+; CHECK: [[HIPTR:%[0-9]+]](p0) = G_FRAME_INDEX %fixed-stack.[[HI_FRAME]]
+; CHECK: [[HI:%[0-9]+]](s64) = G_LOAD [[HIPTR]](p0) :: (invariant load 8 from %fixed-stack.[[HI_FRAME]], align 0)
+define void @take_split_struct([2 x i64]* %ptr, i64, i64, i64,
+                               i64, i64, i64,
+                               [2 x i64] %in) {
+  store [2 x i64] %in, [2 x i64]* %ptr
+  ret void
+}