https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77439
Bug ID: 77439
Summary: [6/7 regression] wrong code for sibcall with
longcall, APCS frame and VFP
Product: gcc
Version: 6.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: ebotcazou at gcc dot gnu.org
Target Milestone: ---
Created attachment 39531
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39531&action=edit
Testcase
The following change:
2014-04-25 Jiong Wang <jiong.w...@arm.com>
* config/arm/predicates.md (call_insn_operand): Add long_call check.
* config/arm/arm.md (sibcall, sibcall_value): Force the address to
reg for long_call.
* config/arm/arm.c (arm_function_ok_for_sibcall): Remove long_call
restriction.
has introduced a bug for sibcalls with longcall, APCS frame and VFP. For a
longcall, any sibcall becomes an indirect sibcall and therefore requires
a register to hold the target address. Now if all the argument registers are
taken, this register will be IP but, for APCS frames and VFP, IP can be used
in the sibcall epilogue to restore the VFP registers, so the target address is
overwritten and the call goes astray. Testcase attached, compile it with e.g.
-mapcs-frame -mfloat-abi=soft -O -foptimize-sibling-calls -ffunction-sections
and you'll see for arm-eabi:
sub ip, fp, #36
vldm ip!, {d8}
sub sp, fp, #28
ldmfd sp, {r4, r5, r6, r7, fp, sp, lr}
bx ip
