https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64539

            Bug ID: 64539
           Summary: [5 regression] cprop_hardreg does not respect clobbers
                    in C_I_F_U
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: vries at gcc dot gnu.org

As discussed in PR64154 comment 2 and 3, the clobbers in
CALL_INSN_FUNCTION_USAGE are in general not registered by
copyprop_hardreg_forward_1.

F.i. in this thumb1 call insn there's a clobber of the ip reg, that is ignored
by cprop_hardreg:
...
(call_insn 141 292 142 13 (parallel [
            (call (mem:SI (symbol_ref:SI ("f2") [flags 0x3]  <function_decl
0x7f8182689100 f2>) [0 f2 S4 A32])
                (const_int 0 [0]))
            (use (const_int 0 [0]))
            (clobber (reg:SI 14 lr))
        ])
/myssd/terguo01/toolchain-build/GCC32RM-424/src/gcc/gcc/testsuite/gcc.dg/vshift-3.c:119
770 {*call_insn}
     (expr_list:REG_CALL_DECL (symbol_ref:SI ("f2") [flags 0x3]  <function_decl
0x7f8182689100 f2>)
        (expr_list:REG_EH_REGION (const_int 0 [0])
            (nil)))
    (expr_list (clobber (reg:SI 12 ip))
        (nil)))
...

I can't rule out that this is a generic bug, so marking tentatively as 5.0
regression.

Reply via email to