On Wed, 9 May 2012, Eric Botcazou wrote: > > This removes the TYPE_IS_SIZETYPE macro and all its uses (by > > assuming it returns zero and applying trivial folding). Sizes > > and bitsizes can still be treat specially by means of knowing > > what the values represent and by means of using helper functions > > that assume you are dealing with "sizes" (in particular size_binop > > and friends and bit_from_pos, byte_from_pos or pos_from_bit). > > Fine with me, if you add the blurb I talked about in the other reply. > > > Bootstrapped and tested on x86_64-unknown-linux-gnu for all languages > > including Ada with the patch optimizing bute_from_pos and pos_from_bit > > Results on our internal testsuite are clean on x86-64 and almost clean on > x86, > an exception being: > > package t is > type x (m : natural) is record > s : string (1 .. m); > r : natural; > b : boolean; > end record; > for x'alignment use 4; > > pragma Pack (x); > end t; > > Without the patches, compiling the package with -gnatR3 yields: > > Representation information for unit t (spec) > -------------------------------------------- > > for x'Object_Size use 17179869248; > for x'Value_Size use ((#1 + 8) * 8) ; > for x'Alignment use 4; > for x use record > m at 0 range 0 .. 30; > s at 4 range 0 .. ((#1 * 8)) - 1; > r at bit offset (((#1 + 4) * 8)) size in bits = 31 > b at bit offset ((((#1 + 7) * 8) + 7)) size in bits = 1 > end record; > > With the patches, this yields: > > Representation information for unit t (spec) > -------------------------------------------- > > for x'Object_Size use 17179869248; > for x'Value_Size use (((#1 + 7) + 1) * 8) ; > for x'Alignment use 4; > for x use record > m at 0 range 0 .. 30; > s at 4 range 0 .. ((#1 * 8)) - 1; > r at bit offset (((#1 + 4) * 8)) size in bits = 31 > b at bit offset ((((#1 + 7) * 8) + 7)) size in bits = 1 > end record; > > so we have lost a simple folding for x'Value_Size (TYPE_ADA_SIZE field).
That's interesting. It is always safe to fold (x + 7) + 1 to (x + 8), independent on whether overflow is defined or not. So this looks like a genuine missed folding (I think that the combiner in tree-ssa-forwprop.c catches this). Or is the above not showing casts in the expression? Folding would be not valid for (unsigned)(signed X + 7) + 1. > > 2012-05-08 Richard Guenther <rguent...@suse.de> > > > > ada/ > > * gcc-interface/cuintp.c (UI_From_gnu): Remove TYPE_IS_SIZETYPE use. > > OK, modulo the formatting: Adjusted and applied. Thanks, Richard. > > Index: trunk/gcc/ada/gcc-interface/cuintp.c > > =================================================================== > > *** trunk.orig/gcc/ada/gcc-interface/cuintp.c 2011-04-11 > > 17:01:30.000000000 > > +0200 --- trunk/gcc/ada/gcc-interface/cuintp.c 2012-05-07 > > 16:43:43.497218058 +0200 *************** UI_From_gnu (tree Input) > > *** 178,186 **** > > if (host_integerp (Input, 0)) > > return UI_From_Int (TREE_INT_CST_LOW (Input)); > > else if (TREE_INT_CST_HIGH (Input) < 0 > > ! && TYPE_UNSIGNED (gnu_type) > > ! && !(TREE_CODE (gnu_type) == INTEGER_TYPE > > ! && TYPE_IS_SIZETYPE (gnu_type))) > > return No_Uint; > > #endif > > > > --- 178,184 ---- > > if (host_integerp (Input, 0)) > > return UI_From_Int (TREE_INT_CST_LOW (Input)); > > else if (TREE_INT_CST_HIGH (Input) < 0 > > ! && TYPE_UNSIGNED (gnu_type)) > > return No_Uint; > > #endif > > && TYPE_UNSIGNED (gnu_type)) on the same line.
