i386: Disallow sibcall for calling ifunc functions with PIC register

Disallow siball when calling ifunc functions with PIC register so that
PIC register can be restored.

gcc/

	PR target/105960
	* config/i386/i386.cc (ix86_function_ok_for_sibcall): Return
	false if PIC register is used when calling ifunc functions.

gcc/testsuite/

	PR target/105960
	* gcc.target/i386/pr105960.c: New test.

(cherry picked from commit fe9765c0b9)

gcc/config/i386/i386.cc

@@ -1015,6 +1015,15 @@ ix86_function_ok_for_sibcall (tree decl, tree exp)
 	}
     }
 
+  if (decl && ix86_use_pseudo_pic_reg ())
+    {
+      /* When PIC register is used, it must be restored after ifunc
+	 function returns.  */
+       cgraph_node *node = cgraph_node::get (decl);
+       if (node && node->ifunc_resolver)
+	 return false;
+    }
+
   /* Otherwise okay.  That also includes certain types of indirect calls.  */
   return true;
 }

gcc/testsuite/gcc.target/i386/pr105960.c

@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-require-ifunc "" } */
+/* { dg-options "-O2 -fpic" } */
+
+__attribute__((target_clones("default","fma")))
+static inline double
+expfull_ref(double x)
+{
+  return __builtin_pow(x, 0.1234);
+}
+
+double
+exp_ref(double x)
+{
+  return expfull_ref(x);
+}
+
+/* { dg-final { scan-assembler "jmp\[ \t\]*expfull_ref@PLT" { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler "call\[ \t\]*expfull_ref@PLT" { target ia32 } } } */