[AArch64] Mark GOT related MEM rtx as const to help RTL loop IV

gcc/
    * config/aarch64/aarch64.c (aarch64_load_symref_appropriately): Mark mem
    as READONLY and NOTRAP for PIC symbol.

  gcc/testsuite/
    * gcc.target/aarch64/got_mem_hoist_1.c: New test.

From-SVN: r225669

gcc/ChangeLog

@@ -1,3 +1,8 @@
+2015-07-10  Jiong Wang  <jiong.wang@arm.com>
+
+	* config/aarch64/aarch64.c (aarch64_load_symref_appropriately): Mark mem
+	as READONLY and NOTRAP for PIC symbol.
+
 2015-07-10  Andrew MacLeod  <amacleod@redhat.com>
 
 	* gimple-predict.h: New file. 

gcc/config/aarch64/aarch64.c

@@ -890,6 +890,8 @@ aarch64_load_symref_appropriately (rtx dest, rtx imm,
       {
 	machine_mode mode = GET_MODE (dest);
 	rtx gp_rtx = pic_offset_table_rtx;
+	rtx insn;
+	rtx mem;
 
 	/* NOTE: pic_offset_table_rtx can be NULL_RTX, because we can reach
 	   here before rtl expand.  Tree IVOPT will generate rtl pattern to
@@ -933,16 +935,27 @@ aarch64_load_symref_appropriately (rtx dest, rtx imm,
 	if (mode == ptr_mode)
 	  {
 	    if (mode == DImode)
-	      emit_insn (gen_ldr_got_small_28k_di (dest, gp_rtx, imm));
+	      insn = gen_ldr_got_small_28k_di (dest, gp_rtx, imm);
 	    else
-	      emit_insn (gen_ldr_got_small_28k_si (dest, gp_rtx, imm));
+	      insn = gen_ldr_got_small_28k_si (dest, gp_rtx, imm);
+
+	    mem = XVECEXP (SET_SRC (insn), 0, 0);
 	  }
 	else
 	  {
 	    gcc_assert (mode == Pmode);
-	    emit_insn (gen_ldr_got_small_28k_sidi (dest, gp_rtx, imm));
+
+	    insn = gen_ldr_got_small_28k_sidi (dest, gp_rtx, imm);
+	    mem = XVECEXP (XEXP (SET_SRC (insn), 0), 0, 0);
 	  }
 
+	/* The operand is expected to be MEM.  Whenever the related insn
+	   pattern changed, above code which calculate mem should be
+	   updated.  */
+	gcc_assert (GET_CODE (mem) == MEM);
+	MEM_READONLY_P (mem) = 1;
+	MEM_NOTRAP_P (mem) = 1;
+	emit_insn (insn);
 	return;
       }
 
@@ -955,6 +968,9 @@ aarch64_load_symref_appropriately (rtx dest, rtx imm,
 	   DImode if dest is dereferenced to access the memeory.
 	   This is why we have to handle three different ldr_got_small
 	   patterns here (two patterns for ILP32).  */
+
+	rtx insn;
+	rtx mem;
 	rtx tmp_reg = dest;
 	machine_mode mode = GET_MODE (dest);
 
@@ -965,16 +981,24 @@ aarch64_load_symref_appropriately (rtx dest, rtx imm,
 	if (mode == ptr_mode)
 	  {
 	    if (mode == DImode)
-	      emit_insn (gen_ldr_got_small_di (dest, tmp_reg, imm));
+	      insn = gen_ldr_got_small_di (dest, tmp_reg, imm);
 	    else
-	      emit_insn (gen_ldr_got_small_si (dest, tmp_reg, imm));
+	      insn = gen_ldr_got_small_si (dest, tmp_reg, imm);
+
+	    mem = XVECEXP (SET_SRC (insn), 0, 0);
 	  }
 	else
 	  {
 	    gcc_assert (mode == Pmode);
-	    emit_insn (gen_ldr_got_small_sidi (dest, tmp_reg, imm));
+
+	    insn = gen_ldr_got_small_sidi (dest, tmp_reg, imm);
+	    mem = XVECEXP (XEXP (SET_SRC (insn), 0), 0, 0);
 	  }
 
+	gcc_assert (GET_CODE (mem) == MEM);
+	MEM_READONLY_P (mem) = 1;
+	MEM_NOTRAP_P (mem) = 1;
+	emit_insn (insn);
 	return;
       }
 

gcc/testsuite/ChangeLog

@@ -1,3 +1,7 @@
+2015-07-10  Jiong Wang  <jiong.wang@arm.com>
+
+	* gcc.target/aarch64/got_mem_hoist_1.c: New test.
+
 2015-07-10  Christophe Lyon  <christophe.lyon@linaro.org>
 
 	* gcc.target/arm/attr_thumb.c: Skip if Thumb is not supported.

gcc/testsuite/gcc.target/aarch64/got_mem_hoist_1.c

@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fpic -fdump-rtl-loop2_invariant" } */
+
+int bar (int);
+int cal (void *);
+
+int
+foo (int a, int bound)
+{
+  int i = 0;
+  int sum = 0;
+
+  for (i; i < bound; i++)
+    sum = cal (bar);
+
+  return sum;
+}
+
+/* The insn which loads function address from GOT table should be moved out
+   of the loop.  */
+/* { dg-final { scan-rtl-dump "Decided" "loop2_invariant" } } */