From: Chris Lattner <sabre@nondot.org>
Date: Tue, 17 Dec 2002 03:15:26 +0000 (+0000)
Subject: Round number of bytes allocated on the stack up to a multiple of 4 so that the
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=3bbe7cc51dd402871d206ca3fb77f84240e0c100;p=oota-llvm.git

Round number of bytes allocated on the stack up to a multiple of 4 so that the
stack remains aligned


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@5095 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp
index fc87a02e3b3..909a79cee70 100644
--- a/lib/Target/X86/X86RegisterInfo.cpp
+++ b/lib/Target/X86/X86RegisterInfo.cpp
@@ -113,10 +113,13 @@ const unsigned* X86RegisterInfo::getCallerSaveRegs() const {
 }
 
 void X86RegisterInfo::emitPrologue(MachineFunction &MF,
-                                   unsigned numBytes) const {
+                                   unsigned NumBytes) const {
   MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
   MachineBasicBlock::iterator MBBI = MBB.begin();
 
+  // Round stack allocation up to a nice alignment to keep the stack aligned
+  NumBytes = (NumBytes + 3) & ~3;
+
   // PUSH ebp
   MachineInstr *MI = BuildMI(X86::PUSHr32, 1).addReg(X86::EBP);
   MBBI = ++MBB.insert(MBBI, MI);
@@ -126,7 +129,7 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF,
   MBBI = ++MBB.insert(MBBI, MI);
 
   // adjust stack pointer: ESP -= numbytes
-  MI  = BuildMI(X86::SUBri32, 2, X86::ESP).addReg(X86::ESP).addZImm(numBytes);
+  MI  = BuildMI(X86::SUBri32, 2, X86::ESP).addReg(X86::ESP).addZImm(NumBytes);
   MBBI = ++MBB.insert(MBBI, MI);
 }