| Message ID | 20151201070737.GA51402@kam.mff.cuni.cz |
|---|---|
| State | New |
| Headers | show |
On Tue, 1 Dec 2015, Jan Hubicka wrote: > Hi, > memory attributes are currently optimized and attached to RTL even when not > optimizing. This is obviously just a wasted effort. Huh, are you sure? What about globals used from different optimize contexts? > Bootstrapped/regtested x86_64-linux, OK? I don't think so. Did you bootstrap with BOOT_CFLAGS="-O0 -g"? Richard. > Honza > * emit-rtl.c (set_mem_attrs, set_mem_attributes_minus_bitpos): > Do not compute memory attributes when not optimizing. > > Index: emit-rtl.c > =================================================================== > --- emit-rtl.c (revision 231081) > +++ emit-rtl.c (working copy) > @@ -336,7 +336,8 @@ static void > set_mem_attrs (rtx mem, mem_attrs *attrs) > { > /* If everything is the default, we can just clear the attributes. */ > - if (mem_attrs_eq_p (attrs, mode_mem_attrs[(int) GET_MODE (mem)])) > + if (!optimize > + || mem_attrs_eq_p (attrs, mode_mem_attrs[(int) GET_MODE (mem)])) > { > MEM_ATTRS (mem) = 0; > return; > @@ -1749,6 +1750,9 @@ set_mem_attributes_minus_bitpos (rtx ref > struct mem_attrs attrs, *defattrs, *refattrs; > addr_space_t as; > > + if (!optimize) > + return; > + > /* It can happen that type_for_mode was given a mode for which there > is no language-level type. In which case it returns NULL, which > we can see here. */ > >
> On Tue, 1 Dec 2015, Jan Hubicka wrote: > > > Hi, > > memory attributes are currently optimized and attached to RTL even when not > > optimizing. This is obviously just a wasted effort. > > Huh, are you sure? What about globals used from different optimize > contexts? Hmm, you are right - we will get worse code quality. The code won't ICE because MEM_ATTRS can legally be NULL - get_mem_attrs will then supply default one for given mode, but we will miss code quality. I will look into disabling mem attrs for non-globals only. It would be nice to get rid of those global persistent RTLs (and make DECL_RTL to be function local hash) Honza
Index: emit-rtl.c =================================================================== --- emit-rtl.c (revision 231081) +++ emit-rtl.c (working copy) @@ -336,7 +336,8 @@ static void set_mem_attrs (rtx mem, mem_attrs *attrs) { /* If everything is the default, we can just clear the attributes. */ - if (mem_attrs_eq_p (attrs, mode_mem_attrs[(int) GET_MODE (mem)])) + if (!optimize + || mem_attrs_eq_p (attrs, mode_mem_attrs[(int) GET_MODE (mem)])) { MEM_ATTRS (mem) = 0; return; @@ -1749,6 +1750,9 @@ set_mem_attributes_minus_bitpos (rtx ref struct mem_attrs attrs, *defattrs, *refattrs; addr_space_t as; + if (!optimize) + return; + /* It can happen that type_for_mode was given a mode for which there is no language-level type. In which case it returns NULL, which we can see here. */