re PR target/79041 (aarch64 backend emits R_AARCH64_ADR_PREL_PG_HI21 relocation…

re PR target/79041 (aarch64 backend emits R_AARCH64_ADR_PREL_PG_HI21 relocation despite -mpc-relative-literal-loads option being used)

Fix PR79041

As described in PR79041, -mcmodel=large -mpc-relative-literal-loads
may be used to avoid generating ADRP/ADD or ADRP/LDR.  However both
trunk and GCC7 may still emit ADRP for some constant pool literals.
Fix this by adding a aarch64_pcrelative_literal_loads check.

gcc/
	PR target/79041
	* config/aarch64/aarch64.c (aarch64_classify_symbol):
	Avoid SYMBOL_SMALL_ABSOLUTE for literals with pc-relative literals
gcc/testsuite/
	* gcc.target/aarch64/pr79041-2.c: New test.

From-SVN: r250478

gcc/ChangeLog

+2017-07-24  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	PR target/79041
+	* config/aarch64/aarch64.c (aarch64_classify_symbol):
+	Avoid SYMBOL_SMALL_ABSOLUTE for literals with pc-relative literals.
+
 2017-07-24  Carl Love  <cel@us.ibm.com>
 
 	* config/rs6000/rs6000-c.c: Add support for built-in functions

gcc/config/aarch64/aarch64.c

@@ -10193,7 +10193,7 @@ aarch64_classify_symbol (rtx x, rtx offset)
 	  /* This is alright even in PIC code as the constant
 	     pool reference is always PC relative and within
 	     the same translation unit.  */
-	  if (CONSTANT_POOL_ADDRESS_P (x))
+	  if (!aarch64_pcrelative_literal_loads && CONSTANT_POOL_ADDRESS_P (x))
 	    return SYMBOL_SMALL_ABSOLUTE;
 	  else
 	    return SYMBOL_FORCE_TO_MEM;

gcc/testsuite/ChangeLog

+2017-07-24  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	PR target/79041
+	* gcc.target/aarch64/pr79041-2.c: New test.
+
 2017-07-24  Carl Love  <cel@us.ibm.com>
 
 	* gcc.target/powerpc/builtins-3-p9-runnable.c: Add new test file for

gcc/testsuite/gcc.target/aarch64/pr79041-2.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -mcmodel=large -mpc-relative-literal-loads" } */
+
+__int128
+t (void)
+{
+  return (__int128)1 << 80;
+}
+
+/* { dg-final { scan-assembler "adr" } } */