From f86eb00f122f3524e256b9a2059a3b37a25583ff Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@intel.com>
Date: Tue, 5 Feb 2019 06:13:06 +0000
Subject: [PATCH] [X86] Connect the default fpsr and dirflag clobbers in inline
 assembly to the registers we have defined for them.

Summary:
We don't currently map these constraints to physical register numbers so they don't make it to the MachineIR representation of inline assembly.

This could have problems for proper dependency tracking in the machine schedulers though I don't have a test case that shows that.

Reviewers: rnk

Reviewed By: rnk

Subscribers: eraman, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57641

llvm-svn: 353141
---
 llvm/lib/Target/X86/X86ISelLowering.cpp              | 8 ++++++++
 llvm/lib/Target/X86/X86RegisterInfo.td               | 2 +-
 llvm/test/CodeGen/X86/inline-asm-default-clobbers.ll | 8 ++++++++
 3 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/CodeGen/X86/inline-asm-default-clobbers.ll

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 18cb4d1..314fed5 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -43006,6 +43006,14 @@ X86TargetLowering::getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
     if (StringRef("{flags}").equals_lower(Constraint))
       return std::make_pair(X86::EFLAGS, &X86::CCRRegClass);
 
+    // dirflag -> DF
+    if (StringRef("{dirflag}").equals_lower(Constraint))
+      return std::make_pair(X86::DF, &X86::DFCCRRegClass);
+
+    // fpsr -> FPSW
+    if (StringRef("{fpsr}").equals_lower(Constraint))
+      return std::make_pair(X86::FPSW, &X86::FPCCRRegClass);
+
     // 'A' means [ER]AX + [ER]DX.
     if (Constraint == "A") {
       if (Subtarget.is64Bit())
diff --git a/llvm/lib/Target/X86/X86RegisterInfo.td b/llvm/lib/Target/X86/X86RegisterInfo.td
index 1deae9aa..50aa84b 100644
--- a/llvm/lib/Target/X86/X86RegisterInfo.td
+++ b/llvm/lib/Target/X86/X86RegisterInfo.td
@@ -287,7 +287,7 @@ def ST6 : X86Reg<"st(6)", 6>, DwarfRegNum<[39, 18, 17]>;
 def ST7 : X86Reg<"st(7)", 7>, DwarfRegNum<[40, 19, 18]>;
 
 // Floating-point status word
-def FPSW : X86Reg<"fpsw", 0>;
+def FPSW : X86Reg<"fpsr", 0>;
 
 // Status flags register.
 //
diff --git a/llvm/test/CodeGen/X86/inline-asm-default-clobbers.ll b/llvm/test/CodeGen/X86/inline-asm-default-clobbers.ll
new file mode 100644
index 0000000..34a77ea
--- /dev/null
+++ b/llvm/test/CodeGen/X86/inline-asm-default-clobbers.ll
@@ -0,0 +1,8 @@
+; RUN: llc < %s -mtriple=i686 -stop-after=expand-isel-pseudos | FileCheck %s
+
+; CHECK: INLINEASM &"", 1, 12, implicit-def early-clobber $df, 12, implicit-def early-clobber $fpsw, 12, implicit-def early-clobber $eflags
+define void @foo() {
+entry:
+  call void asm sideeffect "", "~{dirflag},~{fpsr},~{flags}"()
+  ret void
+}
-- 
2.7.4