Fix prolog/epilog in the presence of alloca

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5087 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index 30095e69dcc888c1369d457d2acfa822ea88c851..c96bbd86b0168a8e03971cbc85937cd848b75784 100644 (file)
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -117,6 +117,14 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF,
   MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
   MachineBasicBlock::iterator MBBI = MBB.begin();
 
+  // PUSH all callee-save registers
+  const unsigned* regs = getCalleeSaveRegs();
+  while (*regs) {
+    MachineInstr *MI = BuildMI(X86::PUSHr32, 1).addReg(*regs);
+    MBBI = ++MBB.insert(MBBI, MI);
+    ++regs;
+  }
+
   // PUSH ebp
   MachineInstr *MI = BuildMI(X86::PUSHr32, 1).addReg(X86::EBP);
   MBBI = ++MBB.insert(MBBI, MI);
@@ -128,14 +136,6 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF,
   // adjust stack pointer: ESP -= numbytes
   MI  = BuildMI(X86::SUBri32, 2, X86::ESP).addReg(X86::ESP).addZImm(numBytes);
   MBBI = ++MBB.insert(MBBI, MI);
-
-  // PUSH all callee-save registers
-  const unsigned* regs = getCalleeSaveRegs();
-  while (*regs) {
-    MI = BuildMI(X86::PUSHr32, 1).addReg(*regs);
-    MBBI = ++MBB.insert(MBBI, MI);
-    ++regs;
-  }
 }
 
 void X86RegisterInfo::emitEpilogue(MachineBasicBlock &MBB,
@@ -144,6 +144,9 @@ void X86RegisterInfo::emitEpilogue(MachineBasicBlock &MBB,
   assert((*MBBI)->getOpcode() == X86::RET &&
          "Can only insert epilog into returning blocks");
 
+  // insert LEAVE
+  MBBI = ++MBB.insert(MBBI, BuildMI(X86::LEAVE, 0));
+
   // POP all callee-save registers in REVERSE ORDER
   static const unsigned regs[] = { X86::EBX, X86::EDI, X86::ESI,
                                    MRegisterInfo::NoRegister };
@@ -152,7 +155,4 @@ void X86RegisterInfo::emitEpilogue(MachineBasicBlock &MBB,
     MachineInstr *MI = BuildMI(X86::POPr32, 0, regs[idx++]);
     MBBI = ++(MBB.insert(MBBI, MI));
   }
-  
-  // insert LEAVE
-  MBB.insert(MBBI, BuildMI(X86::LEAVE, 0));
 }