Re: [PATCH] Fix ICE in ia64 speculation support

[Vladimir Makarov <vmakarov@redhat.com>]

Maxim Kuvyrkov wrote:
> Hi,
>
> This patch fixes minor bug in ia64 speculation support.
>
> The issue is that may_trap_p () can return different results given 
> normal instruction and its speculative version.  E.g., this occurs for 
> (set (reg:DF) (mem:DF)) and (set (reg:DF) (unspec:DF [(mem:DF)] 
> DATA_SPEC)).  The latter is a speculative variant of the former and 
> may_trap_p () always returns 'true' for the speculative version 
> because unspec:DF is considered a random floating point operation that 
> might trap.
>
> This causes an assert, that checks that a speculative insn can stay 
> speculative, fail.  The fix is to use original pattern when calling 
> may_trap_p ().
>
> The bug was reported by Andrey and implicates itself only with '-O2 
> -funroll-loops' (the options tested by default do not include this 
> combination).  The testcase is a copy of 
> gcc.c-torture/execute/20040709-1.c but with forced -funroll-loops.
>
> OK for trunk?
>
>
Sorry, I can reproduce the bug.  I've tried today repository.  No luck.

I think that right solution would be make may_trap_p to understand that 
the insn is speculative.  But without reproducing the bug, I can not be 
sure about my proposal.

Vlad