[AArch64] Revert wrong commit of "Improve TLS Descriptor pattern to release RTL loop IV opt"

Revert the wrong commit of

  2015-08-06    Ramana Radhakrishnan  <ramana.radhakrishnan@arm.com>
	      Jiong Wang  <jiong.wang@arm.com>

	* config/aarch64/aarch64.d (tlsdesc_small_pseudo_<mode>): New pattern.
	* config/aarch64/aarch64.h (reg_class): New enumeration FIXED_REG0.
	(REG_CLASS_NAMES): Likewise.
	(REG_CLASS_CONTENTS): Likewise.
	* config/aarch64/aarch64.c (aarch64_class_max_nregs): Likewise.
	(aarch64_register_move_cost): Likewise.
	(aarch64_load_symref_appropriately): Invoke the new added pattern if
	possible.
	* config/aarch64/constraints.md (Uc0): New constraint.

From-SVN: r226756

gcc/config/aarch64/aarch64.c

@@ -1048,26 +1048,12 @@ aarch64_load_symref_appropriately (rtx dest, rtx imm,
 
 	gcc_assert (mode == Pmode || mode == ptr_mode);
 
-	if (can_create_pseudo_p ())
-	  {
-	    rtx reg = gen_reg_rtx (mode);
-
-	    if (TARGET_ILP32)
-	      emit_insn (gen_tlsdesc_small_pseudo_si (imm, reg));
-	    else
-	      emit_insn (gen_tlsdesc_small_pseudo_di (imm, reg));
-
-	    emit_use (reg);
-	  }
+	/* In ILP32, the got entry is always of SImode size.  Unlike
+	   small GOT, the dest is fixed at reg 0.  */
+	if (TARGET_ILP32)
+	  emit_insn (gen_tlsdesc_small_si (imm));
 	else
-	  {
-	    /* In ILP32, the got entry is always of SImode size.  Unlike
-	       small GOT, the dest is fixed at reg 0.  */
-	    if (TARGET_ILP32)
-	      emit_insn (gen_tlsdesc_small_si (imm));
-	    else
-	      emit_insn (gen_tlsdesc_small_di (imm));
-	  }
+	  emit_insn (gen_tlsdesc_small_di (imm));
 	tp = aarch64_load_tp (NULL);
 
 	if (mode != Pmode)

gcc/config/aarch64/aarch64.md

@@ -4549,23 +4549,6 @@
   [(set_attr "type" "call")
    (set_attr "length" "16")])
 
-;; The same as tlsdesc_small_<mode> except that we don't expose hard register X0
-;; as the destination of set as it will cause trouble for RTL loop iv.
-;; RTL loop iv will abort ongoing optimization once it finds there is hard reg
-;; as destination of set.  This pattern thus could help these tlsdesc
-;; instruction sequences hoisted out of loop.
-(define_insn "tlsdesc_small_pseudo_<mode>"
-  [(set (match_operand:PTR 1 "register_operand" "=r")
-        (unspec:PTR [(match_operand 0 "aarch64_valid_symref" "S")]
-		   UNSPEC_TLSDESC))
-   (clobber (reg:DI R0_REGNUM))
-   (clobber (reg:DI LR_REGNUM))
-   (clobber (reg:CC CC_REGNUM))]
-  "TARGET_TLS_DESC"
-  "adrp\\tx0, %A0\;ldr\\t%<w>1, [x0, #%L0]\;add\\t<w>0, <w>0, %L0\;.tlsdesccall\\t%0\;blr\\t%1"
-  [(set_attr "type" "call")
-   (set_attr "length" "16")])
-
 (define_insn "stack_tie"
   [(set (mem:BLK (scratch))
 	(unspec:BLK [(match_operand:DI 0 "register_operand" "rk")

gcc/testsuite/gcc.target/aarch64/tlsdesc_hoist.c

-/* { dg-do compile } */
-/* { dg-require-effective-target tls_native } */
-/* { dg-options "-O2 -fpic -fdump-rtl-loop2_invariant" } */
-/* { dg-skip-if "-mcmodel=large, no support for -fpic" { aarch64-*-* }  { "-mcmodel=large" } { "" } } */
-
-int cal (int, int);
-__thread int tls_data;
-
-int
-foo (int bound)
-{
-  int i = 0;
-  int sum = 0;
-
-  for (i; i < bound; i++)
-    sum = cal (sum, tls_data);
-
-  return sum;
-}
-
-/* Insn sequences for TLS descriptor should be hoisted out of the loop.  */
-/* { dg-final { scan-rtl-dump "Decided" "loop2_invariant" } } */