Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -2750,6 +2750,11 @@
   if (MF.getTarget().Options.DisableTailCalls)
     isTailCall = false;
 
+  if (Subtarget->isTarget64BitILP32() && Callee->getValueType(0) == MVT::i32) {
+    // Zero-extend the 32-bit Callee address into a 64-bit according to x32 ABI
+    Callee = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i64, Callee);
+  }
+
   bool IsMustTail = CLI.CS && CLI.CS->isMustTailCall();
   if (IsMustTail) {
     // Force this to be a tail call.  The verifier rules are enough to ensure
Index: test/CodeGen/X86/x32-function_pointer-1.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/x32-function_pointer-1.ll
@@ -0,0 +1,20 @@
+; RUN: llc < %s -mtriple=x86_64-linux-gnux32  | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-linux-gnux32 -fast-isel | FileCheck %s
+
+; Test for x32 function pointer tail call
+
+@foo1 = external global void (i8*)*
+@foo2 = external global void (i8*)*
+
+define void @bar(i8* %h) nounwind uwtable {
+entry:
+  %0 = load void (i8*)** @foo1, align 4
+; CHECK: movl	foo1(%rip), %e{{[^,]*}}
+  tail call void %0(i8* %h) nounwind
+; CHECK: callq	*%r{{[^,]*}}
+  %1 = load void (i8*)** @foo2, align 4
+; CHECK: movl	foo2(%rip), %e{{[^,]*}}
+  tail call void %1(i8* %h) nounwind
+; CHECK: jmpq	*%r{{[^,]*}}
+  ret void
+}
Index: test/CodeGen/X86/x32-function_pointer-2.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/x32-function_pointer-2.ll
@@ -0,0 +1,21 @@
+; RUN: llc < %s -mtriple=x86_64-linux-gnux32 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-linux-gnux32 -fast-isel | FileCheck %s
+
+; Test call function pointer with function argument
+;
+; void bar (void * h, void (*foo) (void *))
+;    {
+;      foo (h);
+;      foo (h);
+;    }
+
+
+define void @bar(i8* %h, void (i8*)* nocapture %foo) nounwind {
+entry:
+  tail call void %foo(i8* %h) nounwind
+; CHECK: mov{{l|q}}	%{{e|r}}si, %{{e|r}}[[REG:.*]]{{d?}}
+; CHECK: callq	*%r[[REG]]
+  tail call void %foo(i8* %h) nounwind
+; CHECK: jmpq	*%r{{[^,]*}}
+  ret void
+}
Index: test/CodeGen/X86/x32-function_pointer-3.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/x32-function_pointer-3.ll
@@ -0,0 +1,30 @@
+; RUN: llc < %s -mtriple=x86_64-linux-gnux32 | FileCheck %s
+; RUN: llc < %s -mtriple=x86_64-linux-gnux32 -fast-isel | FileCheck %s
+
+; Test calling function pointer passed in struct
+
+;    The fuction argument `h' in
+
+;    struct foo {
+;      void (*f) (void);
+;      int i;
+;    };
+;    void
+;    bar (struct foo h)
+;    {
+;      h.f ();
+;    }
+
+;    is passed in the 64-bit %rdi register.  The `f' field is in the lower 32
+;    bits of %rdi register and the `i' field is in the upper 32 bits of %rdi
+;    register.  We need to zero-extend %edi to %rdi before branching via %rdi.
+
+define void @bar(i64 %h.coerce) nounwind {
+entry:
+  %h.sroa.0.0.extract.trunc = trunc i64 %h.coerce to i32
+  %0 = inttoptr i32 %h.sroa.0.0.extract.trunc to void ()*
+; CHECK: movl	%edi, %e[[REG:.*]]
+  tail call void %0() nounwind
+; CHECK: jmpq	*%r[[REG]]
+  ret void
+}