Index: lib/Target/X86/X86Subtarget.cpp
===================================================================
--- lib/Target/X86/X86Subtarget.cpp
+++ lib/Target/X86/X86Subtarget.cpp
@@ -139,12 +139,20 @@
     return X86II::MO_NO_FLAG;
 
   assert(!isTargetCOFF());
+ 
+  const Function *F = dyn_cast_or_null<Function>(GV);
+
+  if (is64Bit() && getTargetTriple().isOSLinux() &&
+    F && (CallingConv::X86_RegCall == F->getCallingConv()))
+    // Lazy binding is disabled in regcall calling convention on 64 bit linux
+    // because regcall uses XMM8-XMM15 for parameter passing and according to 
+    // the ABI, PLT might clobber those registers.
+    return X86II::MO_GOTPCREL;
 
   if (isTargetELF())
     return X86II::MO_PLT;
 
   if (is64Bit()) {
-    auto *F = dyn_cast_or_null<Function>(GV);
     if (F && F->hasFnAttribute(Attribute::NonLazyBind))
       // If the function is marked as non-lazy, generate an indirect call
       // which loads from the GOT directly. This avoids runtime overhead
Index: test/CodeGen/X86/regcall-no-plt.ll
===================================================================
--- test/CodeGen/X86/regcall-no-plt.ll
+++ test/CodeGen/X86/regcall-no-plt.ll
@@ -0,0 +1,43 @@
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -relocation-model=pic < %s | FileCheck %s
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; According to x86-64 psABI, xmm0-xmm7 can be used to pass function parameters.  
+;; However regcall calling convention uses also xmm8-xmm15 to pass function  
+;; parameters which violates x86-64 psABI. 
+;; Detail info about it can be found at:
+;; https://sourceware.org/bugzilla/show_bug.cgi?id=21265
+;;
+;; We encounter the violation symptom when using PIC with lazy binding 
+;; optimization.
+;; In that case the PLT mechanism as described in x86_64 psABI will
+;; not preserve xmm8-xmm15 registers and will lead to miscompilation.
+;;
+;; The agreed solution is to disable PLT for regcall calling convention 
+;; in linux 64 bit.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+declare void @lazy()
+declare x86_regcallcc void @regcall_not_lazy()
+
+; CHECK-LABEL: foo:
+; CHECK:  callq lazy@PLT
+; CHECK:  callq *regcall_not_lazy@GOTPCREL(%rip)
+define void @foo() nounwind {
+  call void @lazy()
+  call void @regcall_not_lazy()
+  ret void
+}
+
+; CHECK-LABEL: tail_call_regcall:
+; CHECK:   jmpq *regcall_not_lazy@GOTPCREL(%rip)
+define void @tail_call_regcall() nounwind {
+  tail call void @regcall_not_lazy()
+  ret void
+}
+
+; CHECK-LABEL: tail_call_regular:
+; CHECK:   jmp lazy
+define void @tail_call_regular() nounwind {
+  tail call void @lazy()
+  ret void
+}