From: Hal Finkel <hfinkel@anl.gov>
Date: Fri, 28 Jun 2013 22:29:56 +0000 (+0000)
Subject: PPC: Ignore spill/restore requests for VRSAVE (except on Darwin)
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=6a636a813f33b46b3271ec8517ee1936a0c92c9f;p=oota-llvm.git

PPC: Ignore spill/restore requests for VRSAVE (except on Darwin)

This fixes PR16418, which reports that a function calling
__builtin_unwind_init() asserts. The cause is that this generates a
spill/restore for VRSAVE, and we support that only on Darwin (because VRSAVE is
only really used on Darwin).

The test case checks only that we don't crash. We can add correctness checks
once someone verifies what behavior the function is supposed to have.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185235 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/PowerPC/PPCFrameLowering.cpp b/lib/Target/PowerPC/PPCFrameLowering.cpp
index dc734d13482..4c57cf632fb 100644
--- a/lib/Target/PowerPC/PPCFrameLowering.cpp
+++ b/lib/Target/PowerPC/PPCFrameLowering.cpp
@@ -1145,6 +1145,12 @@ PPCFrameLowering::spillCalleeSavedRegisters(MachineBasicBlock &MBB,
   
   for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
     unsigned Reg = CSI[i].getReg();
+    // Only Darwin actually uses the VRSAVE register, but it can still appear
+    // here if, for example, @llvm.eh.unwind.init() is used.  If we're not on
+    // Darwin, ignore it.
+    if (Reg == PPC::VRSAVE && !Subtarget.isDarwinABI())
+      continue;
+
     // CR2 through CR4 are the nonvolatile CR fields.
     bool IsCRField = PPC::CR2 <= Reg && Reg <= PPC::CR4;
 
@@ -1294,6 +1300,12 @@ PPCFrameLowering::restoreCalleeSavedRegisters(MachineBasicBlock &MBB,
   for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
     unsigned Reg = CSI[i].getReg();
 
+    // Only Darwin actually uses the VRSAVE register, but it can still appear
+    // here if, for example, @llvm.eh.unwind.init() is used.  If we're not on
+    // Darwin, ignore it.
+    if (Reg == PPC::VRSAVE && !Subtarget.isDarwinABI())
+      continue;
+
     if (Reg == PPC::CR2) {
       CR2Spilled = true;
       // The spill slot is associated only with CR2, which is the
diff --git a/test/CodeGen/PowerPC/unwind-dw2.ll b/test/CodeGen/PowerPC/unwind-dw2.ll
new file mode 100644
index 00000000000..e58edff65d5
--- /dev/null
+++ b/test/CodeGen/PowerPC/unwind-dw2.ll
@@ -0,0 +1,15 @@
+; RUN: llc < %s
+target datalayout = "E-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-f128:128:128-v128:128:128-n32:64"
+target triple = "powerpc64-unknown-linux-gnu"
+
+; Function Attrs: nounwind
+define void @foo() #0 {
+entry:
+  call void @llvm.eh.unwind.init()
+  ret void
+}
+
+; Function Attrs: nounwind
+declare void @llvm.eh.unwind.init() #0
+
+attributes #0 = { nounwind }