On 2 April 2014 17:34, Joern Rennecke <joern.renne...@embecosm.com> wrote:
> Hmm, the sanity check in new_seginfo caused a boostrap failure
> building libjava on x86.
> There was a block with CODE_LABEL as basic block head, otherwise empty.
I've added the testcase - and a bit more detail on this issue - in the PR.
I've attached an updated patch, which skips past the CODE_LABEL.
And this one bootstraps on i686-pc-linuc-gnu.
2014-04-02 Joern Rennecke <joern.renne...@embecosm.com>
gcc:
PR rtl-optimization/60651
* mode-switching.c (optimize_mode_switching): Make sure to emit
sets of a lower numbered entity before sets of a higher numbered
entity to a mode of the same or lower priority.
When creating a seginfo for a basic block that starts with a code
label, move the insertion point past the code label.
(new_seginfo): Document and enforce requirement that
NOTE_INSN_BASIC_BLOCK only appears for empty blocks.
* doc/tm.texi.in: Document ordering constraint for emitted mode sets.
* doc/tm.texi: Regenerate.
gcc/testsuite:
PR rtl-optimization/60651
* gcc.target/epiphany/mode-switch.c: New test.
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index f7024a7..b8ca17e 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -9778,6 +9778,8 @@ for @var{entity}. For any fixed @var{entity},
@code{mode_priority_to_mode}
Generate one or more insns to set @var{entity} to @var{mode}.
@var{hard_reg_live} is the set of hard registers live at the point where
the insn(s) are to be inserted.
+Sets of a lower numbered entity will be emitted before sets of a higher
+numbered entity to a mode of the same or lower priority.
@end defmac
@node Target Attributes
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 6dcbde4..d793d26 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -7447,6 +7447,8 @@ for @var{entity}. For any fixed @var{entity},
@code{mode_priority_to_mode}
Generate one or more insns to set @var{entity} to @var{mode}.
@var{hard_reg_live} is the set of hard registers live at the point where
the insn(s) are to be inserted.
+Sets of a lower numbered entity will be emitted before sets of a higher
+numbered entity to a mode of the same or lower priority.
@end defmac
@node Target Attributes
diff --git a/gcc/mode-switching.c b/gcc/mode-switching.c
index 88543b2..088156c 100644
--- a/gcc/mode-switching.c
+++ b/gcc/mode-switching.c
@@ -96,12 +96,18 @@ static void make_preds_opaque (basic_block, int);
/* This function will allocate a new BBINFO structure, initialized
- with the MODE, INSN, and basic block BB parameters. */
+ with the MODE, INSN, and basic block BB parameters.
+ INSN may not be a NOTE_INSN_BASIC_BLOCK, unless it is en empty
+ basic block; that allows us later to insert instructions in a FIFO-like
+ manner. */
static struct seginfo *
new_seginfo (int mode, rtx insn, int bb, HARD_REG_SET regs_live)
{
struct seginfo *ptr;
+
+ gcc_assert (!NOTE_INSN_BASIC_BLOCK_P (insn)
+ || insn == BB_END (NOTE_BASIC_BLOCK (insn)));
ptr = XNEW (struct seginfo);
ptr->mode = mode;
ptr->insn_ptr = insn;
@@ -534,7 +540,13 @@ optimize_mode_switching (void)
break;
if (e)
{
- ptr = new_seginfo (no_mode, BB_HEAD (bb), bb->index, live_now);
+ rtx ins_pos = BB_HEAD (bb);
+ if (LABEL_P (ins_pos))
+ ins_pos = NEXT_INSN (ins_pos);
+ gcc_assert (NOTE_INSN_BASIC_BLOCK_P (ins_pos));
+ if (ins_pos != BB_END (bb))
+ ins_pos = NEXT_INSN (ins_pos);
+ ptr = new_seginfo (no_mode, ins_pos, bb->index, live_now);
add_seginfo (info + bb->index, ptr);
bitmap_clear_bit (transp[bb->index], j);
}
@@ -733,7 +745,15 @@ optimize_mode_switching (void)
{
emitted = true;
if (NOTE_INSN_BASIC_BLOCK_P (ptr->insn_ptr))
- emit_insn_after (mode_set, ptr->insn_ptr);
+ /* We need to emit the insns in a FIFO-like manner,
+ i.e. the first to be emitted at our insertion
+ point ends up first in the instruction steam.
+ Because we made sure that NOTE_INSN_BASIC_BLOCK is
+ only used for initially empty basic blocks, we
+ can archive this by appending at the end of
+ the block. */
+ emit_insn_after
+ (mode_set, BB_END (NOTE_BASIC_BLOCK (ptr->insn_ptr)));
else
emit_insn_before (mode_set, ptr->insn_ptr);
}
--- /dev/null 2014-03-19 18:18:19.244212660 +0000
+++ b/gcc/testsuite/gcc.target/epiphany/mode-switch.c 2014-03-25
13:31:41.186140611 +0000
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler "#-917506" } } */
+/* PR 60651 */
+
+int a;
+int c;
+
+void __attribute__((interrupt))
+misc_handler (void) {
+ a*= c;
+}
