From 2a2e9d54e95f01eaa5626dcdf57950e9e6f95f2c Mon Sep 17 00:00:00 2001
From: Chad Rosier <mcrosier@apple.com>
Date: Fri, 11 May 2012 18:51:55 +0000
Subject: [PATCH] [fast-isel] Cleaner fix for when we're unable to handle a
 non-double multi-reg retval.  Hoists check before emitting the call to avoid
 unnecessary work. rdar://11430407 PR12796

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156628 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/ARM/ARMFastISel.cpp                | 25 ++++++++++++++++---
 .../ARM/fast-isel-call-multi-reg-return.ll    | 17 +++++++++++++
 2 files changed, 38 insertions(+), 4 deletions(-)
 create mode 100644 test/CodeGen/ARM/fast-isel-call-multi-reg-return.ll

diff --git a/lib/Target/ARM/ARMFastISel.cpp b/lib/Target/ARM/ARMFastISel.cpp
index f49a5d3f83c..02bb5f41fea 100644
--- a/lib/Target/ARM/ARMFastISel.cpp
+++ b/lib/Target/ARM/ARMFastISel.cpp
@@ -2014,7 +2014,8 @@ bool ARMFastISel::FinishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
 
       // Finally update the result.
       UpdateValueMap(I, ResultReg);
-    } else if (RVLocs.size() == 1) {
+    } else {
+      assert(RVLocs.size() == 1 &&"Can't handle non-double multi-reg retvals!");
       EVT CopyVT = RVLocs[0].getValVT();
 
       // Special handling for extended integers.
@@ -2030,9 +2031,6 @@ bool ARMFastISel::FinishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
 
       // Finally update the result.
       UpdateValueMap(I, ResultReg);
-    } else {
-      // Can't handle non-double multi-reg retvals.
-      return false;
     }
   }
 
@@ -2144,6 +2142,15 @@ bool ARMFastISel::ARMEmitLibcall(const Instruction *I, RTLIB::Libcall Call) {
   // TODO: For now if we have long calls specified we don't handle the call.
   if (EnableARMLongCalls) return false;
 
+  // Can't handle non-double multi-reg retvals.
+  if (RetVT != MVT::isVoid && RetVT != MVT::i32) {  
+    SmallVector<CCValAssign, 16> RVLocs;
+    CCState CCInfo(CC, false, *FuncInfo.MF, TM, RVLocs, *Context);
+    CCInfo.AnalyzeCallResult(RetVT, CCAssignFnForCall(CC, true));
+    if (RVLocs.size() >= 2 && RetVT != MVT::f64)
+      return false;
+  }
+
   // Set up the argument vectors.
   SmallVector<Value*, 8> Args;
   SmallVector<unsigned, 8> ArgRegs;
@@ -2247,6 +2254,16 @@ bool ARMFastISel::SelectCall(const Instruction *I,
   // TODO: For now if we have long calls specified we don't handle the call.
   if (EnableARMLongCalls) return false;
 
+  // Can't handle non-double multi-reg retvals.
+  if (RetVT != MVT::isVoid && RetVT != MVT::i1 && RetVT != MVT::i8 &&
+      RetVT != MVT::i16 && RetVT != MVT::i32) {
+    SmallVector<CCValAssign, 16> RVLocs;
+    CCState CCInfo(CC, false, *FuncInfo.MF, TM, RVLocs, *Context);
+    CCInfo.AnalyzeCallResult(RetVT, CCAssignFnForCall(CC, true));
+    if (RVLocs.size() >= 2 && RetVT != MVT::f64)
+      return false;
+  }
+
   // Set up the argument vectors.
   SmallVector<Value*, 8> Args;
   SmallVector<unsigned, 8> ArgRegs;
diff --git a/test/CodeGen/ARM/fast-isel-call-multi-reg-return.ll b/test/CodeGen/ARM/fast-isel-call-multi-reg-return.ll
new file mode 100644
index 00000000000..14721a4d802
--- /dev/null
+++ b/test/CodeGen/ARM/fast-isel-call-multi-reg-return.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -O0 -relocation-model=dynamic-no-pic -mtriple=armv7-apple-ios | FileCheck %s --check-prefix=ARM
+; RUN: llc < %s -O0 -relocation-model=dynamic-no-pic -mtriple=thumbv7-apple-ios | FileCheck %s --check-prefix=THUMB
+
+; Fast-isel can't handle non-double multi-reg retvals.
+; This test just check to make sure we don't hit the assert in FinishCall.
+define <16 x i8> @foo() nounwind ssp {
+entry:
+  ret <16 x i8> zeroinitializer
+}
+
+define void @t1() nounwind ssp {
+entry:
+; ARM: @t1
+; THUMB: @t1
+  %call = call <16 x i8> @foo()
+  ret void
+}
-- 
2.34.1