re PR target/43961 ([ARM thumb] "branch out of range" with thumb1_output_casesi)

2013-01-15  Joseph Myers  <joseph@codesourcery.com>
	    Mikael Pettersson  <mikpe@it.uu.se>

	PR target/43961
	* config/arm/arm.h (ADDR_VEC_ALIGN): Align SImode jump tables for
	Thumb.
	(ASM_OUTPUT_CASE_LABEL): Remove.
	(ASM_OUTPUT_BEFORE_CASE_LABEL): Define to empty.
	* final.c (shorten_branches): Update alignment of labels before
	jump tables if CASE_VECTOR_SHORTEN_MODE.

Co-Authored-By: Mikael Pettersson <mikpe@it.uu.se>

From-SVN: r195208

gcc/ChangeLog

+2013-01-15  Joseph Myers  <joseph@codesourcery.com>
+	    Mikael Pettersson  <mikpe@it.uu.se>
+
+	PR target/43961
+	* config/arm/arm.h (ADDR_VEC_ALIGN): Align SImode jump tables for
+	Thumb.
+	(ASM_OUTPUT_CASE_LABEL): Remove.
+	(ASM_OUTPUT_BEFORE_CASE_LABEL): Define to empty.
+	* final.c (shorten_branches): Update alignment of labels before
+	jump tables if CASE_VECTOR_SHORTEN_MODE.
+
 2013-01-15  Richard Biener  <rguenther@suse.de>
 
 	PR bootstrap/55961

gcc/config/arm/arm.h

@@ -2129,20 +2129,13 @@ extern int making_const_table;
 	asm_fprintf (STREAM, "\tpop {%r}\n", REGNO);	\
     } while (0)
 
-/* Jump table alignment is explicit in ASM_OUTPUT_CASE_LABEL.  */
-#define ADDR_VEC_ALIGN(JUMPTABLE) 0
-
-/* This is how to output a label which precedes a jumptable.  Since
-   Thumb instructions are 2 bytes, we may need explicit alignment here.  */
-#undef  ASM_OUTPUT_CASE_LABEL
-#define ASM_OUTPUT_CASE_LABEL(FILE, PREFIX, NUM, JUMPTABLE)		\
-  do									\
-    {									\
-      if (TARGET_THUMB && GET_MODE (PATTERN (JUMPTABLE)) == SImode)	\
-        ASM_OUTPUT_ALIGN (FILE, 2);					\
-      (*targetm.asm_out.internal_label) (FILE, PREFIX, NUM);		\
-    }									\
-  while (0)
+#define ADDR_VEC_ALIGN(JUMPTABLE)	\
+  ((TARGET_THUMB && GET_MODE (PATTERN (JUMPTABLE)) == SImode) ? 2 : 0)
+
+/* Alignment for case labels comes from ADDR_VEC_ALIGN; avoid the
+   default alignment from elfos.h.  */
+#undef ASM_OUTPUT_BEFORE_CASE_LABEL
+#define ASM_OUTPUT_BEFORE_CASE_LABEL(FILE, PREFIX, NUM, TABLE) /* Empty.  */
 
 /* Make sure subsequent insns are aligned after a TBB.  */
 #define ASM_OUTPUT_CASE_END(FILE, NUM, JUMPTABLE)	\

gcc/final.c

@@ -1182,6 +1182,29 @@ shorten_branches (rtx first)
 	  if (LABEL_P (insn))
 	    {
 	      int log = LABEL_TO_ALIGNMENT (insn);
+
+#ifdef CASE_VECTOR_SHORTEN_MODE
+	      /* If the mode of a following jump table was changed, we
+		 may need to update the alignment of this label.  */
+	      rtx next;
+	      bool next_is_jumptable;
+
+	      next = next_nonnote_insn (insn);
+	      next_is_jumptable = next && JUMP_TABLE_DATA_P (next);
+	      if ((JUMP_TABLES_IN_TEXT_SECTION
+		   || readonly_data_section == text_section)
+		  && next_is_jumptable)
+		{
+		  int newlog = ADDR_VEC_ALIGN (next);
+		  if (newlog != log)
+		    {
+		      log = newlog;
+		      LABEL_TO_ALIGNMENT (insn) = log;
+		      something_changed = 1;
+		    }
+		}
+#endif
+
 	      if (log > insn_current_align)
 		{
 		  int align = 1 << log;