[Patch 2/2 PR78561] Recalculate constant pool size before emitting it

gcc/

	PR rtl-optimization/78561
	* varasm.c (recompute_pool_offsets): New.
	(output_constant_pool): Call it.

gcc/testsuite/

	PR rtl-optimization/78561
	* gcc.target/aarch64/pr78561.c: New.

From-SVN: r243183

gcc/ChangeLog

 2016-12-02  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	PR rtl-optimization/78561
+	* varasm.c (recompute_pool_offsets): New.
+	(output_constant_pool): Call it.
+
+2016-12-02  James Greenhalgh  <james.greenhalgh@arm.com>
+
+	PR rtl-optimization/78561
 	* config/rs6000/rs6000.c (rs6000_reg_live_or_pic_offset_p) Rename
 	get_pool_size to get_pool_size_upper_bound.
 	(rs6000_stack_info): Likewise.

gcc/testsuite/ChangeLog

+2016-12-02  James Greenhalgh  <james.greenhalgh@arm.com>
+
+	PR rtl-optimization/78561
+	* gcc.target/aarch64/pr78561.c: New.
+
 2016-12-02  Bin Cheng  <bin.cheng@arm.com>
 
 	* gcc.dg/fold-bopcond-1.c: New test.

gcc/varasm.c

@@ -3942,6 +3942,29 @@ output_constant_pool_1 (struct constant_descriptor_rtx *desc,
   return;
 }
 
+/* Recompute the offsets of entries in POOL, and the overall size of
+   POOL.  Do this after calling mark_constant_pool to ensure that we
+   are computing the offset values for the pool which we will actually
+   emit.  */
+
+static void
+recompute_pool_offsets (struct rtx_constant_pool *pool)
+{
+  struct constant_descriptor_rtx *desc;
+  pool->offset = 0;
+
+  for (desc = pool->first; desc ; desc = desc->next)
+    if (desc->mark)
+      {
+	  /* Recalculate offset.  */
+	unsigned int align = desc->align;
+	pool->offset += (align / BITS_PER_UNIT) - 1;
+	pool->offset &= ~ ((align / BITS_PER_UNIT) - 1);
+	desc->offset = pool->offset;
+	pool->offset += GET_MODE_SIZE (desc->mode);
+      }
+}
+
 /* Mark all constants that are referenced by SYMBOL_REFs in X.
    Emit referenced deferred strings.  */
 
@@ -4060,6 +4083,11 @@ output_constant_pool (const char *fnname ATTRIBUTE_UNUSED,
      case we do not need to output the constant.  */
   mark_constant_pool ();
 
+  /* Having marked the constant pool entries we'll actually emit, we
+     now need to rebuild the offset information, which may have become
+     stale.  */
+  recompute_pool_offsets (pool);
+
 #ifdef ASM_OUTPUT_POOL_PROLOGUE
   ASM_OUTPUT_POOL_PROLOGUE (asm_out_file, fnname, fndecl, pool->offset);
 #endif