From 08ecb711ac9294dcbd560a53c0345b86aaf1d15f Mon Sep 17 00:00:00 2001
From: Bruno Cardoso Lopes <bruno.cardoso@gmail.com>
Date: Fri, 16 Sep 2011 20:58:28 +0000
Subject: [PATCH] Fix PR10884.

This PR basically reports a problem where a crash in generated code
happened due to %rbp being clobbered:

  pushq %rbp
  movq  %rsp, %rbp
  ....
  vmovmskps %ymm12, %ebp
  ....
  movq  %rbp, %rsp
  popq  %rbp
  ret

Since Eric's r123367 commit, the default stack alignment for x86 32-bit
has changed to be 16-bytes. Since then, the MaxStackAlignmentHeuristicPass
hasn't been really used, but with AVX it becomes useful again, since per
ABI compliance we don't always align the stack to 256-bit, but only when
there are 256-bit incoming arguments.

ReserveFP was only used by this pass, but there's no RA target hook that
uses getReserveFP() to check for the presence of FP (since nothing was
triggering the pass to run, the uses of getReserveFP() were removed
through time without being noticed). Change this pass to use
setForceFramePointer, which is properly called by MachineFunction
hasFP method.

The testcase is very big and dependent on RA, not sure if it's worth
adding to test/CodeGen/X86.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139939 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/X86/X86MachineFunctionInfo.h | 8 --------
 lib/Target/X86/X86RegisterInfo.cpp      | 2 +-
 2 files changed, 1 insertion(+), 9 deletions(-)

diff --git a/lib/Target/X86/X86MachineFunctionInfo.h b/lib/Target/X86/X86MachineFunctionInfo.h
index 97e88b57cb5..b0bb313ec63 100644
--- a/lib/Target/X86/X86MachineFunctionInfo.h
+++ b/lib/Target/X86/X86MachineFunctionInfo.h
@@ -53,10 +53,6 @@ class X86MachineFunctionInfo : public MachineFunctionInfo {
   /// relocation models.
   unsigned GlobalBaseReg;
 
-  /// ReserveFP - whether the function should reserve the frame pointer
-  /// when allocating, even if there may not actually be a frame pointer used.
-  bool ReserveFP;
-
   /// VarArgsFrameIndex - FrameIndex for start of varargs area.
   int VarArgsFrameIndex;
   /// RegSaveFrameIndex - X86-64 vararg func register save area.
@@ -91,7 +87,6 @@ public:
       TailCallReturnAddrDelta(0),
       SRetReturnReg(0),
       GlobalBaseReg(0),
-      ReserveFP(false),
       VarArgsFrameIndex(0),
       RegSaveFrameIndex(0),
       VarArgsGPOffset(0),
@@ -119,9 +114,6 @@ public:
   unsigned getGlobalBaseReg() const { return GlobalBaseReg; }
   void setGlobalBaseReg(unsigned Reg) { GlobalBaseReg = Reg; }
 
-  bool getReserveFP() const { return ReserveFP; }
-  void setReserveFP(bool reserveFP) { ReserveFP = reserveFP; }
-
   int getVarArgsFrameIndex() const { return VarArgsFrameIndex; }
   void setVarArgsFrameIndex(int Idx) { VarArgsFrameIndex = Idx; }
 
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 0e96991af96..ba8be69fe35 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -822,7 +822,7 @@ namespace {
       for (unsigned i = 0, e = RI.getNumVirtRegs(); i != e; ++i) {
         unsigned Reg = TargetRegisterInfo::index2VirtReg(i);
         if (RI.getRegClass(Reg)->getAlignment() > StackAlignment) {
-          FuncInfo->setReserveFP(true);
+          FuncInfo->setForceFramePointer(true);
           return true;
         }
       }