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final.c (shorten_branches): Do not align labels for jump tables.

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* final.c (shorten_branches): Do not align labels for jump tables.
	(final_scan_insn): Use JUMP_TABLE_DATA_P.

	* gcc.dg/falign-labels-1.c: New test.

Co-Authored-By: Maxim Kuvyrkov <maxim@codesourcery.com>

From-SVN: r147824
This commit is contained in:
Mark Mitchell 2009-05-23 17:56:14 +00:00 • committed by Mark Mitchell
parent 94324dae55
commit 0676c39392
4 changed files with 93 additions and 51 deletions
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5
gcc/ChangeLog
View file

@ -1,3 +1,8 @@
2009-05-23 Mark Mitchell <mark@codesourcery.com>
* final.c (shorten_branches): Do not align labels for jump tables.
(final_scan_insn): Use JUMP_TABLE_DATA_P.
2009-05-23 Eric Botcazou <ebotcazou@adacore.com>
* doc/passes.texi: Standardize spelling of RTL, Tree and Tree SSA.

95
gcc/final.c
View file

@ -901,6 +901,7 @@ shorten_branches (rtx first ATTRIBUTE_UNUSED)
if (LABEL_P (insn))
{
rtx next;
bool next_is_jumptable;
/* Merge in alignments computed by compute_alignments. */
log = LABEL_TO_ALIGNMENT (insn);
@ -910,31 +911,30 @@ shorten_branches (rtx first ATTRIBUTE_UNUSED)
max_skip = LABEL_TO_MAX_SKIP (insn);
}
log = LABEL_ALIGN (insn);
if (max_log < log)
{
max_log = log;
max_skip = LABEL_ALIGN_MAX_SKIP;
}
next = next_nonnote_insn (insn);
next_is_jumptable = next && JUMP_TABLE_DATA_P (next);
if (!next_is_jumptable)
{
log = LABEL_ALIGN (insn);
if (max_log < log)
{
max_log = log;
max_skip = LABEL_ALIGN_MAX_SKIP;
}
}
/* ADDR_VECs only take room if read-only data goes into the text
section. */
if (JUMP_TABLES_IN_TEXT_SECTION
|| readonly_data_section == text_section)
if (next && JUMP_P (next))
{
rtx nextbody = PATTERN (next);
if (GET_CODE (nextbody) == ADDR_VEC
|| GET_CODE (nextbody) == ADDR_DIFF_VEC)
{
log = ADDR_VEC_ALIGN (next);
if (max_log < log)
{
max_log = log;
max_skip = LABEL_ALIGN_MAX_SKIP;
}
}
}
if ((JUMP_TABLES_IN_TEXT_SECTION
|| readonly_data_section == text_section)
&& next_is_jumptable)
{
log = ADDR_VEC_ALIGN (next);
if (max_log < log)
{
max_log = log;
max_skip = LABEL_ALIGN_MAX_SKIP;
}
}
LABEL_TO_ALIGNMENT (insn) = max_log;
LABEL_TO_MAX_SKIP (insn) = max_skip;
max_log = 0;
@ -2023,48 +2023,41 @@ final_scan_insn (rtx insn, FILE *file, int optimize ATTRIBUTE_UNUSED,
app_disable ();
next = next_nonnote_insn (insn);
if (next != 0 && JUMP_P (next))
/* If this label is followed by a jump-table, make sure we put
the label in the read-only section. Also possibly write the
label and jump table together. */
if (next != 0 && JUMP_TABLE_DATA_P (next))
{
rtx nextbody = PATTERN (next);
/* If this label is followed by a jump-table,
make sure we put the label in the read-only section. Also
possibly write the label and jump table together. */
if (GET_CODE (nextbody) == ADDR_VEC
|| GET_CODE (nextbody) == ADDR_DIFF_VEC)
{
#if defined(ASM_OUTPUT_ADDR_VEC) || defined(ASM_OUTPUT_ADDR_DIFF_VEC)
/* In this case, the case vector is being moved by the
target, so don't output the label at all. Leave that
to the back end macros. */
/* In this case, the case vector is being moved by the
target, so don't output the label at all. Leave that
to the back end macros. */
#else
if (! JUMP_TABLES_IN_TEXT_SECTION)
{
int log_align;
if (! JUMP_TABLES_IN_TEXT_SECTION)
{
int log_align;
switch_to_section (targetm.asm_out.function_rodata_section
(current_function_decl));
switch_to_section (targetm.asm_out.function_rodata_section
(current_function_decl));
#ifdef ADDR_VEC_ALIGN
log_align = ADDR_VEC_ALIGN (next);
log_align = ADDR_VEC_ALIGN (next);
#else
log_align = exact_log2 (BIGGEST_ALIGNMENT / BITS_PER_UNIT);
log_align = exact_log2 (BIGGEST_ALIGNMENT / BITS_PER_UNIT);
#endif
ASM_OUTPUT_ALIGN (file, log_align);
}
else
switch_to_section (current_function_section ());
ASM_OUTPUT_ALIGN (file, log_align);
}
else
switch_to_section (current_function_section ());
#ifdef ASM_OUTPUT_CASE_LABEL
ASM_OUTPUT_CASE_LABEL (file, "L", CODE_LABEL_NUMBER (insn),
next);
ASM_OUTPUT_CASE_LABEL (file, "L", CODE_LABEL_NUMBER (insn),
next);
#else
targetm.asm_out.internal_label (file, "L", CODE_LABEL_NUMBER (insn));
targetm.asm_out.internal_label (file, "L", CODE_LABEL_NUMBER (insn));
#endif
#endif
break;
}
break;
}
if (LABEL_ALT_ENTRY_P (insn))
output_alternate_entry_point (file, insn);

5
gcc/testsuite/ChangeLog
View file

@ -1,3 +1,8 @@
2009-05-23 Mark Mitchell <mark@codesourcery.com>
Maxim Kuvyrkov <maxim@codesourcery.com>
* gcc.dg/falign-labels-1.c: New test.
2009-05-23 Eric Botcazou <ebotcazou@adacore.com>
* gnat.dg/specs/rep_clause3.ads: New test.

39
gcc/testsuite/gcc.dg/falign-labels-1.c Normal file
View file

@ -0,0 +1,39 @@
/* { dg-do run } */
/* { dg-options "-falign-labels=8" { target { ! { m68k*-*-* || fido*-*-* } } } } */
/* On ARMv7-A CPUs, this test resulted in incorrect code generation.
The code generated for the switch statement expected the jump table
to immediately follow the jump instruction, but -falign-labels
caused the label preceding the table to be aligned. */
/* M68K and fido only support -falign-labels argument <= 2. */
volatile int x;
int main(void)
{
int y;
x = 0;
switch(x)
{
case 0:
y = 2 * x;
break;
case 1:
y = -3 * x;
break;
case 2:
y = x + 5;
break;
case 3:
y = x - 7;
break;
default:
break;
}
x = y;
return 0;
}