From a7b65c30a3645dbd2ec46c728332e6ab6183fdf0 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Wed, 18 Jul 2007 16:29:46 +0000
Subject: [PATCH] It's not necessary to do rounding for alloca operations when
 the requested alignment is equal to the stack alignment.

llvm-svn: 40004
---
 llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 10 +++++-----
 llvm/test/CodeGen/X86/alloca-align-rounding.ll     |  9 +++++++++
 2 files changed, 14 insertions(+), 5 deletions(-)
 create mode 100644 llvm/test/CodeGen/X86/alloca-align-rounding.ll

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index d4651fd6abc0..9256faabeb15 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2327,13 +2327,13 @@ void SelectionDAGLowering::visitAlloca(AllocaInst &I) {
   AllocSize = DAG.getNode(ISD::MUL, IntPtr, AllocSize,
                           getIntPtrConstant(TySize));
 
-  // Handle alignment.  If the requested alignment is less than or equal to the
-  // stack alignment, ignore it and round the size of the allocation up to the
-  // stack alignment size.  If the size is greater than the stack alignment, we
-  // note this in the DYNAMIC_STACKALLOC node.
+  // Handle alignment.  If the requested alignment is less than the stack
+  // alignment, ignore it and round the size of the allocation up to the stack
+  // alignment size.  If the size is greater than or equal to the stack
+  // alignment, we note this in the DYNAMIC_STACKALLOC node.
   unsigned StackAlign =
     TLI.getTargetMachine().getFrameInfo()->getStackAlignment();
-  if (Align <= StackAlign) {
+  if (Align < StackAlign) {
     Align = 0;
     // Add SA-1 to the size.
     AllocSize = DAG.getNode(ISD::ADD, AllocSize.getValueType(), AllocSize,
diff --git a/llvm/test/CodeGen/X86/alloca-align-rounding.ll b/llvm/test/CodeGen/X86/alloca-align-rounding.ll
new file mode 100644
index 000000000000..899dbffd4f67
--- /dev/null
+++ b/llvm/test/CodeGen/X86/alloca-align-rounding.ll
@@ -0,0 +1,9 @@
+; RUN: llvm-as < %s | llc -march=x86-64 | not grep and
+
+declare void @bar(<2 x i64>* %n)
+
+define void @foo(i32 %h) {
+  %p = alloca <2 x i64>, i32 %h
+  call void @bar(<2 x i64>* %p)
+  ret void
+}