[Bug target/38952] [4.4 Regression] EH does not work.

[dave dot korn dot cygwin at gmail dot com]

------- Comment #7 from dave dot korn dot cygwin at gmail dot com  2009-01-24 
06:23 -------
Not IRA-related, it seems, but reload-backend interaction.  -fno-ira doesn't
make any difference to the generated code to calculate the frame pointer for
the jmp_buf.  In a non-IRA build, pass 172r.lreg has:

(insn 49 48 51 2 (set (mem:SI (reg/f:SI 63) [0 S4 A8])
        (reg/f:SI 20 frame)) 41 {*movsi_1} (nil))

and pass 173r.greg has

(insn 73 48 49 2 (set (reg:SI 1 dx)
        (plus:SI (reg/f:SI 7 sp)
            (const_int 80 [0x50]))) 209 {*lea_1} (nil))

(insn 49 73 51 2 (set (mem:SI (reg/f:SI 0 ax [63]) [0 S4 A8])
        (reg:SI 1 dx)) 41 {*movsi_1} (nil))

and here we can see that it's reload doing the FP elimination:

Reloads for insn # 49
Reload 0: reload_out (SI) = (mem:SI (reg/f:SI 0 ax [63]) [0 S4 A8])
        NO_REGS, RELOAD_FOR_OUTPUT (opnum = 0), optional
        reload_out_reg: (mem:SI (reg/f:SI 0 ax [63]) [0 S4 A8])
Reload 1: reload_in (SI) = (plus:SI (reg/f:SI 7 sp)
                                                    (const_int 80 [0x50]))
        GENERAL_REGS, RELOAD_FOR_INPUT (opnum = 1)
        reload_in_reg: (plus:SI (reg/f:SI 7 sp)
                                                    (const_int 80 [0x50]))
        reload_reg_rtx: (reg:SI 1 dx)


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38952