From 42fcf79f36c07f30827087bcbf3f04d0a45ac2f8 Mon Sep 17 00:00:00 2001
From: David Majnemer <david.majnemer@gmail.com>
Date: Thu, 5 Mar 2015 18:50:12 +0000
Subject: [PATCH] X86: Optimize address mode matching for FRAME_ALLOC_RECOVER
 nodes

We know that the absolute symbol will be less than 2GB and thus will
always fit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231389 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp | 1 +
 lib/Target/X86/X86ISelDAGToDAG.cpp              | 9 +++++++++
 test/CodeGen/X86/frameescape.ll                 | 8 ++++----
 3 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index 17eff944c62..5898da41c7f 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -95,6 +95,7 @@ std::string SDNode::getOperationName(const SelectionDAG *G) const {
   case ISD::GLOBAL_OFFSET_TABLE:        return "GLOBAL_OFFSET_TABLE";
   case ISD::RETURNADDR:                 return "RETURNADDR";
   case ISD::FRAMEADDR:                  return "FRAMEADDR";
+  case ISD::FRAME_ALLOC_RECOVER:        return "FRAME_ALLOC_RECOVER";
   case ISD::READ_REGISTER:              return "READ_REGISTER";
   case ISD::WRITE_REGISTER:             return "WRITE_REGISTER";
   case ISD::FRAME_TO_ARGS_OFFSET:       return "FRAME_TO_ARGS_OFFSET";
diff --git a/lib/Target/X86/X86ISelDAGToDAG.cpp b/lib/Target/X86/X86ISelDAGToDAG.cpp
index 8d50ae1584e..42715562a7c 100644
--- a/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -1004,6 +1004,15 @@ bool X86DAGToDAGISel::MatchAddressRecursively(SDValue N, X86ISelAddressMode &AM,
 
   switch (N.getOpcode()) {
   default: break;
+  case ISD::FRAME_ALLOC_RECOVER: {
+    if (!AM.hasSymbolicDisplacement())
+      if (const auto *ESNode = dyn_cast<ExternalSymbolSDNode>(N.getOperand(0)))
+        if (ESNode->getOpcode() == ISD::TargetExternalSymbol) {
+          AM.ES = ESNode->getSymbol();
+          return false;
+        }
+    break;
+  }
   case ISD::Constant: {
     uint64_t Val = cast<ConstantSDNode>(N)->getSExtValue();
     if (!FoldOffsetIntoAddress(Val, AM))
diff --git a/test/CodeGen/X86/frameescape.ll b/test/CodeGen/X86/frameescape.ll
index 621dbe2d276..b48672d3808 100644
--- a/test/CodeGen/X86/frameescape.ll
+++ b/test/CodeGen/X86/frameescape.ll
@@ -16,20 +16,20 @@ define void @print_framealloc_from_fp(i8* %fp) {
   %b = bitcast i8* %b.i8 to i32*
   %b.val = load i32, i32* %b
   call i32 (i8*, ...)* @printf(i8* getelementptr ([10 x i8]* @str, i32 0, i32 0), i32 %b.val)
+  store i32 42, i32* %b
   ret void
 }
 
 ; CHECK-LABEL: print_framealloc_from_fp:
 ; CHECK: movq %rcx, %[[parent_fp:[a-z]+]]
-; CHECK: movabsq $.Lalloc_func$frame_escape_0, %[[offs:[a-z]+]]
-; CHECK: movl (%[[parent_fp]],%[[offs]]), %edx
+; CHECK: movl .Lalloc_func$frame_escape_0(%[[parent_fp]]), %edx
 ; CHECK: leaq {{.*}}(%rip), %[[str:[a-z]+]]
 ; CHECK: movq %[[str]], %rcx
 ; CHECK: callq printf
-; CHECK: movabsq $.Lalloc_func$frame_escape_1, %[[offs:[a-z]+]]
-; CHECK: movl (%[[parent_fp]],%[[offs]]), %edx
+; CHECK: movl .Lalloc_func$frame_escape_1(%[[parent_fp]]), %edx
 ; CHECK: movq %[[str]], %rcx
 ; CHECK: callq printf
+; CHECK: movl    $42, .Lalloc_func$frame_escape_1(%[[parent_fp]])
 ; CHECK: retq
 
 define void @alloc_func() {