Index: lib/Target/Sparc/LeonFeatures.td
===================================================================
--- lib/Target/Sparc/LeonFeatures.td
+++ lib/Target/Sparc/LeonFeatures.td
@@ -58,6 +58,14 @@
   "LEON erratum fix: Replace FMULS instruction with FMULD and relevant conversion instructions" 
 >;
 
+def PreventRoundChange : SubtargetFeature<
+  "prvntroundchange",
+  "PreventRoundChange",
+  "true",
+  "LEON3 erratum fix: Prevent any rounding mode change "
+  "request: use only the round-to-nearest rounding mode"
+>;                       
+
 def FixAllFDIVSQRT : SubtargetFeature<
   "fixallfdivsqrt",
   "FixAllFDIVSQRT",
Index: lib/Target/Sparc/LeonPasses.h
===================================================================
--- lib/Target/Sparc/LeonPasses.h
+++ lib/Target/Sparc/LeonPasses.h
@@ -84,6 +84,20 @@
   }
 };
 
+class LLVM_LIBRARY_VISIBILITY PreventRoundChange
+    : public LEONMachineFunctionPass {
+public:
+  static char ID;
+
+  PreventRoundChange(TargetMachine &tm);
+  bool runOnMachineFunction(MachineFunction &MF) override;
+
+  const char *getPassName() const override {
+    return "PreventRoundChange: Leon erratum fix: prevent any rounding mode "
+           "change request: use only the round-to-nearest rounding mode";
+  }
+};
+
 class LLVM_LIBRARY_VISIBILITY FixAllFDIVSQRT : public LEONMachineFunctionPass {
 public:
   static char ID;
Index: lib/Target/Sparc/LeonPasses.cpp
===================================================================
--- lib/Target/Sparc/LeonPasses.cpp
+++ lib/Target/Sparc/LeonPasses.cpp
@@ -16,6 +16,7 @@
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
@@ -327,3 +328,52 @@
 
   return Modified;
 }
+
+//*****************************************************************************
+//**** PreventRoundChange pass
+//*****************************************************************************
+// To prevent any explicit change of the default rounding mode, this pass
+// detects any call of the fesetround function and removes this call from the
+// list of generated operations. A warning is generated to ensure the user
+// knows this has happened.
+//
+// Fixes erratum in UT699 LEON 3 processor
+
+char PreventRoundChange::ID = 0;
+
+PreventRoundChange::PreventRoundChange(TargetMachine &tm)
+    : LEONMachineFunctionPass(tm, ID) {}
+
+bool PreventRoundChange::runOnMachineFunction(MachineFunction &MF) {
+  Subtarget = &MF.getSubtarget<SparcSubtarget>();
+
+  bool Modified = false;
+  for (auto MFI = MF.begin(), E = MF.end(); MFI != E; ++MFI) {
+    MachineBasicBlock &MBB = *MFI;
+    for (auto MBBI = MBB.begin(), E = MBB.end(); MBBI != E; ++MBBI) {
+      MachineInstr &MI = *MBBI;
+      unsigned Opcode = MI.getOpcode();
+      if (Opcode == SP::CALL && MI.getNumOperands() > 0) {
+        MachineOperand &MO = MI.getOperand(0);
+
+        if (MO.isGlobal()) {
+          StringRef FuncName = MO.getGlobal()->getName();
+          if (FuncName.compare_lower("fesetround") == 0) {
+            MachineBasicBlock::iterator NMBBI = std::next(MBBI);
+            emitOptimizationRemark(
+                MF.getFunction()->getContext(), getPassName(), *MF.getFunction(),
+                MI.getDebugLoc(), "Warning: You are using the prvntroundchange "
+                                  "option to prevent rounding changes caused "
+                                  "by LEON errata. A call to fesetround to be "
+                                  "removed from the output.");
+            MI.eraseFromParent();
+            MBBI = NMBBI;
+            Modified = true;
+          }
+        }
+      }
+    }
+  }
+
+  return Modified;
+}
Index: lib/Target/Sparc/SparcSubtarget.h
===================================================================
--- lib/Target/Sparc/SparcSubtarget.h
+++ lib/Target/Sparc/SparcSubtarget.h
@@ -48,6 +48,7 @@
   bool FixFSMULD;
   bool ReplaceFMULS;
   bool FixAllFDIVSQRT;
+  bool PreventRoundChange;
 
   SparcInstrInfo InstrInfo;
   SparcTargetLowering TLInfo;
@@ -90,6 +91,7 @@
   bool insertNOPLoad() const { return InsertNOPLoad; }
   bool fixFSMULD() const { return FixFSMULD; }
   bool replaceFMULS() const { return ReplaceFMULS; }
+  bool preventRoundChange() const { return PreventRoundChange; }
   bool fixAllFDIVSQRT() const { return FixAllFDIVSQRT; }
 
   /// ParseSubtargetFeatures - Parses features string setting specified
Index: lib/Target/Sparc/SparcSubtarget.cpp
===================================================================
--- lib/Target/Sparc/SparcSubtarget.cpp
+++ lib/Target/Sparc/SparcSubtarget.cpp
@@ -42,6 +42,7 @@
   InsertNOPLoad = false;
   FixFSMULD = false;
   ReplaceFMULS = false;
+  PreventRoundChange = false;
   FixAllFDIVSQRT = false;
 
   // Determine default and user specified characteristics
Index: lib/Target/Sparc/SparcTargetMachine.cpp
===================================================================
--- lib/Target/Sparc/SparcTargetMachine.cpp
+++ lib/Target/Sparc/SparcTargetMachine.cpp
@@ -157,6 +157,9 @@
   {
     addPass(new ReplaceFMULS(getSparcTargetMachine()));
   }
+  if (this->getSparcTargetMachine().getSubtargetImpl()->preventRoundChange()) {
+	addPass(new PreventRoundChange(getSparcTargetMachine()));
+  }
   if (this->getSparcTargetMachine().getSubtargetImpl()->fixAllFDIVSQRT())
   {
     addPass(new FixAllFDIVSQRT(getSparcTargetMachine()));
Index: test/CodeGen/SPARC/LeonPreventRoundChangePassUT.ll
===================================================================
--- test/CodeGen/SPARC/LeonPreventRoundChangePassUT.ll
+++ test/CodeGen/SPARC/LeonPreventRoundChangePassUT.ll
@@ -0,0 +1,65 @@
+; RUN: llc %s -O0 -march=sparc -mcpu=ut699 -o - | FileCheck %s -check-prefix=NO_ROUND_FUNC
+; RUN: llc %s -O0 -march=sparc -mcpu=leon3 -mattr=+prvntroundchange -o - | FileCheck %s -check-prefix=NO_ROUND_FUNC
+
+; RUN: llc %s -O0 -march=sparc -mcpu=ut699 -mattr=-prvntroundchange -o - | FileCheck %s -check-prefix=ROUND_FUNC
+; RUN: llc %s -O0 -march=sparc -mcpu=leon3  -o - | FileCheck %s -check-prefix=ROUND_FUNC
+
+
+; NO_ROUND_FUNC-LABEL: test_round_change
+; NO_ROUND_FUNC-NOT: fesetround
+
+; ROUND_FUNC-LABEL: test_round_change
+; ROUND_FUNC: fesetround
+
+; ModuleID = '<stdin>'
+target datalayout = "E-m:e-p:32:32-i64:64-f128:64-n32-S64"
+target triple = "sparc-unknown--eabi"
+
+@.str = private unnamed_addr constant [17 x i8] c"-((-a)*b) != a*b\00", align 1
+@.str.1 = private unnamed_addr constant [7 x i8] c"test.c\00", align 1
+@__PRETTY_FUNCTION__.mult = private unnamed_addr constant [12 x i8] c"void mult()\00", align 1
+
+; Function Attrs: nounwind
+define void @test_round_change() #0 {
+entry:
+  %a = alloca double, align 8
+  %b = alloca double, align 8
+  %x = alloca float, align 4
+  store double 1.100000e+00, double* %a, align 8
+  store double 1.010000e+01, double* %b, align 8
+  store float 0x400921FA00000000, float* %x, align 4
+  %call = call i32 @fesetround(i32 2048) #2
+  %0 = load double, double* %a, align 8
+  %sub = fsub double -0.000000e+00, %0
+  %1 = load double, double* %b, align 8
+  %mul = fmul double %sub, %1
+  %sub1 = fsub double -0.000000e+00, %mul
+  %2 = load double, double* %a, align 8
+  %3 = load double, double* %b, align 8
+  %mul2 = fmul double %2, %3
+  %cmp = fcmp une double %sub1, %mul2
+  br i1 %cmp, label %cond.true, label %cond.false
+
+cond.true:                                        ; preds = %entry
+  br label %cond.end
+
+cond.false:                                       ; preds = %entry
+  call void @__assert_fail(i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i32 0, i32 0), i8* getelementptr inbounds ([7 x i8], [7 x i8]* @.str.1, i32 0, i32 0), i32 10, i8* getelementptr inbounds ([12 x i8], [12 x i8]* @__PRETTY_FUNCTION__.mult, i32 0, i32 0)) #3
+  unreachable
+                                                  ; No predecessors!
+  br label %cond.end
+
+cond.end:                                         ; preds = %4, %cond.true
+  ret void
+}
+
+; Function Attrs: nounwind
+declare i32 @fesetround(i32) #0
+
+; Function Attrs: noreturn nounwind
+declare void @__assert_fail(i8*, i8*, i32, i8*) #1
+
+attributes #0 = { nounwind "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { noreturn nounwind "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #2 = { nounwind }
+attributes #3 = { noreturn nounwind }
\ No newline at end of file