From e0de8f4efbbf821644093e95e3a3a04e4d8e09fa Mon Sep 17 00:00:00 2001
From: Petar Jovanovic <petar.jovanovic@imgtec.com>
Date: Tue, 12 May 2015 17:14:05 +0000
Subject: [PATCH] [Mips] Return false for isFPCloseToIncomingSP()

On Mips, frame pointer points to the same side of the frame as the stack
pointer. This function is used to decide where to put register scavenging
spill slot. So far, it was put on the wrong side of the frame, and thus it
was too far away from $fp when frame was larger than 2^15 bytes.

Patch by Vladimir Radosavljevic.

http://reviews.llvm.org/D8895

llvm-svn: 237153
---
 llvm/lib/Target/Mips/MipsFrameLowering.h           |  2 ++
 .../CodeGen/Mips/emergency-spill-slot-near-fp.ll   | 32 ++++++++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 llvm/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll

diff --git a/llvm/lib/Target/Mips/MipsFrameLowering.h b/llvm/lib/Target/Mips/MipsFrameLowering.h
index 96d1e29..0b51830 100644
--- a/llvm/lib/Target/Mips/MipsFrameLowering.h
+++ b/llvm/lib/Target/Mips/MipsFrameLowering.h
@@ -32,6 +32,8 @@ public:
 
   bool hasFP(const MachineFunction &MF) const override;
 
+  bool isFPCloseToIncomingSP() const override { return false; }
+
   void
   eliminateCallFramePseudoInstr(MachineFunction &MF,
                                 MachineBasicBlock &MBB,
diff --git a/llvm/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll b/llvm/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll
new file mode 100644
index 0000000..3dc1cde7
--- /dev/null
+++ b/llvm/test/CodeGen/Mips/emergency-spill-slot-near-fp.ll
@@ -0,0 +1,32 @@
+; Check that register scavenging spill slot is close to $fp.
+; RUN: llc -march=mipsel -O0 < %s | FileCheck %s
+
+; CHECK: sw ${{.*}}, 4($fp)
+; CHECK: lw ${{.*}}, 4($fp)
+
+define i32 @main(i32 signext %argc, i8** %argv) "no-frame-pointer-elim"="true" {
+entry:
+  %retval = alloca i32, align 4
+  %argc.addr = alloca i32, align 4
+  %argv.addr = alloca i8**, align 4
+  %v0 = alloca <16 x i8>, align 16
+  %.compoundliteral = alloca <16 x i8>, align 16
+  %v1 = alloca <16 x i8>, align 16
+  %.compoundliteral1 = alloca <16 x i8>, align 16
+  %unused_variable = alloca [16384 x i32], align 4
+  %result = alloca <16 x i8>, align 16
+  store i32 0, i32* %retval
+  store i32 %argc, i32* %argc.addr, align 4
+  store i8** %argv, i8*** %argv.addr, align 4
+  store <16 x i8> <i8 1, i8 2, i8 3, i8 4, i8 5, i8 6, i8 7, i8 8, i8 9, i8 10, i8 11, i8 12, i8 13, i8 14, i8 15, i8 16>, <16 x i8>* %.compoundliteral
+  %0 = load <16 x i8>, <16 x i8>* %.compoundliteral
+  store <16 x i8> %0, <16 x i8>* %v0, align 16
+  store <16 x i8> zeroinitializer, <16 x i8>* %.compoundliteral1
+  %1 = load <16 x i8>, <16 x i8>* %.compoundliteral1
+  store <16 x i8> %1, <16 x i8>* %v1, align 16
+  %2 = load <16 x i8>, <16 x i8>* %v0, align 16
+  %3 = load <16 x i8>, <16 x i8>* %v1, align 16
+  %mul = mul <16 x i8> %2, %3
+  store <16 x i8> %mul, <16 x i8>* %result, align 16
+  ret i32 0
+}
-- 
2.7.4