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[Bug target/52642] New: SH Target: libstdc++ failures due to call insn swapped before prologue frame insns
- From: "olegendo at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 20 Mar 2012 20:32:36 +0000
- Subject: [Bug target/52642] New: SH Target: libstdc++ failures due to call insn swapped before prologue frame insns
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52642
Bug #: 52642
Summary: SH Target: libstdc++ failures due to call insn swapped
before prologue frame insns
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: olegendo@gcc.gnu.org
CC: kkojima@gcc.gnu.org
Target: sh*-*-*
Carry over from PR 51244 comment #33 ...
Looking into the libstdc++ failures for sh4-unknown-linux-gnu,
it seems that the call insn was swapped before prologue frame insns
and then it makes unwinder confused. -fno-delayed-branch also stops
that swapping for these failing cases. The patch below works for me.
* config/sh/sh.c (sh_expand_prologue): Emit blockage at the end
of prologue for unwinder and profiler.
--- ORIG/trunk/gcc/config/sh/sh.c 2012-03-06 10:28:32.000000000 +0900
+++ trunk/gcc/config/sh/sh.c 2012-03-14 20:22:15.000000000 +0900
@@ -7234,6 +7234,13 @@ sh_expand_prologue (void)
emit_insn (gen_shcompact_incoming_args ());
}
+ /* If we are profiling, make sure no instructions are scheduled before
+ the call to mcount. Similarly if some call instructions are swapped
+ before frame related insns, it'll make unwinder confused because
+ currently SH has no unwind info for function epilogues. */
+ if (crtl->profile || flag_exceptions || flag_unwind_tables)
+ emit_insn (gen_blockage ());
+
if (flag_stack_usage_info)
current_function_static_stack_size = stack_usage;
}