On Thu, 16 Apr 2015, Tom de Vries wrote: > [stage1 ping^2] > On 10-03-15 16:30, Tom de Vries wrote: > > [stage1 ping] > > On 22-02-15 14:13, Tom de Vries wrote: > > > On 19-02-15 14:03, Richard Biener wrote: > > > > On Thu, 19 Feb 2015, Tom de Vries wrote: > > > > > > > > > On 19-02-15 11:29, Tom de Vries wrote: > > > > > > Hi, > > > > > > > > > > > > I'm posting this patch series for stage1: > > > > > > - 0001-Disable-lang_hooks.gimplify_expr-in-free_lang_data.patch > > > > > > - 0002-Add-gimple_find_sub_bbs.patch > > > > > > - 0003-Factor-optimize_va_list_gpr_fpr_size-out-of-pass_std.patch > > > > > > - 0004-Handle-internal_fn-in-operand_equal_p.patch > > > > > > - 0005-Postpone-expanding-va_arg-until-pass_stdarg.patch > > > > > > > > > > > > The patch series - based on Michael's initial patch - postpones > > > > > > expanding > > > > > > va_arg > > > > > > until pass_stdarg, which makes pass_stdarg more robust. > > > > > > > > > > > > Bootstrapped and reg-tested on x86_64 using all languages, with > > > > > > unix/ and > > > > > > unix/-m32 testing. > > > > > > > > > > > > I'll post the patches in reply to this email. > > > > > > > > > > > > > > > > This patch postpones expanding va_arg until pass_stdarg. > > > > > > > > > > We add a new internal function IFN_VA_ARG. During gimplification, we > > > > > map > > > > > VA_ARG_EXPR onto a CALL_EXPR with IFN_VA_ARG, which is then gimplified > > > > > in to a > > > > > gimple_call. At pass_stdarg, we expand the IFN_VA_ARG gimple_call into > > > > > actual > > > > > code. > > > > > > > > > > There are a few implementation details worth mentioning: > > > > > - passing the type beyond gimplification is done by adding a NULL > > > > > pointer- > > > > > to-type to IFN_VA_ARG. > > > > > - there is special handling for IFN_VA_ARG that would be most suited > > > > > to be > > > > > placed in gimplify_va_arg_expr. However, that function lacks the > > > > > scope for > > > > > the special handling, so it's placed awkwardly in > > > > > gimplify_modify_expr. > > > > > - there's special handling in case the va_arg type is variable-sized. > > > > > gimplify_modify_expr adds a WITH_SIZE_EXPR to the CALL_EXPR > > > > > IFN_VA_ARG for > > > > > variable-sized types. However, this is gimplified into a > > > > > gimple_call which > > > > > does not have the possibility to wrap it's result in a > > > > > WITH_SIZE_EXPR. So > > > > > we're adding the size argument of the WITH_SIZE_EXPR as argument to > > > > > IFN_VA_ARG, and at expansion in pass_stdarg, wrap the result of the > > > > > gimplification of IFN_VA_ARG in a WITH_SIZE_EXPR, such that the > > > > > subsequent > > > > > gimplify_assign will generate a memcpy if necessary. > > > > > - when gimplifying the va_arg argument ap, it may not be addressable. > > > > > So > > > > > gimplification will generate a copy ap.1 = ap, and use &ap.1 as > > > > > argument. > > > > > This means that we have to copy back the ap.1 value to ap after > > > > > IFN_VA_ARG. > > > > > The copy is classified by the va_list_gpr/fpr_size optimization as > > > > > an > > > > > escape, so it inhibits optimization. The tree-ssa/stdarg-2.c f15 > > > > > update is > > > > > because of that. > > > > > > > > > > OK for stage1? > > > > > > > > Looks mostly good, though it looks like with -O0 this doesn't delay > > > > lowering of va-arg and thus won't "fix" offloading. Can you instead > > > > introduce a PROP_gimple_lva, provide it by the stdarg pass and add > > > > a pass_lower_vaarg somewhere where pass_lower_complex_O0 is run > > > > that runs of !PROP_gimple_lva (and also provides it), and require > > > > PROP_gimple_lva by pass_expand? (just look for PROP_gimple_lcx for > > > > the complex stuff to get an idea what needs to be touched) > > > > > > > > > > Updated according to comments. > > > > > > Furthermore (having updated the patch series to recent trunk), I'm > > > dropping the > > > ACCEL_COMPILER bit in pass_stdarg::gate. AFAIU the comment there relates > > > to this > > > patch. > > > > > > Retested as before. > > > > > > OK for stage1? > > > > > > > Ping. > > Ping again. > > Patch originally posted at: > https://gcc.gnu.org/ml/gcc-patches/2015-02/msg01332.html .
Ok. Thanks, Richard. > Thanks, > - Tom > > > > Btw, I'm wondering if as run-time optimization we can tentatively set > > > PROP_gimple_lva at the start of the gimple pass, and unset it in > > > gimplify_va_arg_expr. That way we would avoid the loop in > > > expand_ifn_va_arg_1 > > > (over all bbs and gimples) in functions without va_arg. > > > > > > > Taken care of in follow-up patch 5b.
