https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67260
Bug ID: 67260
Summary: [sh] Register spill bug for sibcall+complex+softfloat
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: bugdal at aerifal dot cx
Target Milestone: ---
Created attachment 36205
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=36205&action=edit
Preprocessed C source file demonstrating the bug
cacoshl() from musl's complex math library produces an error with all versions
of GCC tested, up through 5.2.0, when sibcall optimization is enabled:
src/complex/cacoshl.c: In function 'cacoshl':
src/complex/cacoshl.c:7:1: error: unable to find a register to spill in class
'SIBCALL_REGS'
}
^
src/complex/cacoshl.c:7:1: error: this is the insn:
(call_insn/j 12 11 13 2 (parallel [
(set (reg:DC 0 r0)
(call (mem:SI (symbol_ref:SI ("cacosh") [flags 0x43]
<function_decl 0x7f754b09aca8 cacosh>) [0 cacosh S4 A32])
(const_int 0 [0])))
(use (reg:SI 154 fpscr0))
(clobber (scratch:SI))
(return)
]) src/complex/cacoshl.c:6 335 {sibcall_value_pcrel}
(expr_list:REG_DEAD (reg:SI 154 fpscr0)
(expr_list:REG_DEAD (reg:DC 4 r4)
(expr_list:REG_CALL_DECL (symbol_ref:SI ("cacosh") [flags 0x43]
<function_decl 0x7f754b09aca8 cacosh>)
(nil))))
(expr_list:DC (use (reg:DC 4 r4))
(nil)))
src/complex/cacoshl.c:7: confused by earlier errors, bailing out
Using -fno-optimize-sibling-calls makes the error go away. The error also does
not occur on sh4 (in the default configuration), which has fpu, only on sh2
with soft-float.
I'm attaching the preprocessed output of cacoshl.c that can be used to
reproduce the error. I don't have a simpler testcase at the moment.
