From: Cameron Esfahani <dirty@apple.com>
Date: Fri, 8 Oct 2010 10:31:30 +0000 (+0000)
Subject: Small patch to restore home register stack space allocation for the Win64 case. ... 
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=d7b8d91d4a2a284bbe9ef6f32b3c25daa7ea0513;p=oota-llvm.git

Small patch to restore home register stack space allocation for the Win64 case.  Add test case.  This code eventually needs to be tighter, since it's always allocating it, even in leaf routines.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116056 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 66f9612e027..27226d885d7 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -1701,8 +1701,12 @@ X86TargetLowering::LowerFormalArguments(SDValue Chain,
         TotalNumXMMRegs = 0;
 
       if (IsWin64) {
+        const TargetFrameInfo &TFI = *getTargetMachine().getFrameInfo();
+        // Get to the caller-allocated home save location.  Add 8 to account
+        // for the return address.
+        int HomeOffset = TFI.getOffsetOfLocalArea() + 8;
         FuncInfo->setRegSaveFrameIndex(
-          MFI->CreateFixedObject(1, NumIntRegs * 8, false));
+          MFI->CreateFixedObject(1, NumIntRegs * 8 + HomeOffset, false));
         FuncInfo->setVarArgsFrameIndex(FuncInfo->getRegSaveFrameIndex());
       } else {
         // For X86-64, if there are vararg parameters that are passed via
diff --git a/test/CodeGen/X86/win64_params.ll b/test/CodeGen/X86/win64_params.ll
new file mode 100644
index 00000000000..0b67368e04f
--- /dev/null
+++ b/test/CodeGen/X86/win64_params.ll
@@ -0,0 +1,11 @@
+; RUN: llc < %s -mtriple=x86_64-pc-win32 | FileCheck %s
+
+; Verify that the 5th and 6th parameters are coming from the correct location
+; on the stack.
+define i32 @f6(i32 %p1, i32 %p2, i32 %p3, i32 %p4, i32 %p5, i32 %p6) nounwind readnone optsize {
+entry:
+; CHECK: movl    80(%rsp), %eax
+; CHECK: addl    72(%rsp), %eax
+  %add = add nsw i32 %p6, %p5
+  ret i32 %add
+}