| Message ID | Ze63iegnAMjJjInd@tucnak |
|---|---|
| State | New |
| Headers | show |
| Series | bitint, v2: Avoid rewriting large/huge _BitInt vars into SSA after bitint lowering [PR114278] | expand |
On Mon, 11 Mar 2024, Jakub Jelinek wrote: > On Sat, Mar 09, 2024 at 12:25:42PM +0100, Richard Biener wrote: > > Ideally we?d clear TREE_ADDRESSABLE but set DECL_NOT_GIMPLE_REG, > > I think the analysis where we check the base would be a more > > appropriate place to enforce that. > > So like this? Hm, I was thinking of non_rewritable_lvalue_p/non_rewritable_mem_ref_base though that requires duplicating, so I guess handling in maybe_optimize_var would work. I do now wonder whether setting DECL_NOT_GIMPLE_REG_P in bitfield lowering would prevail? (sorry for approving the earlier patch now, I was too quick and didn't remember the discussion) Richard. > Bootstrapped/regtested on x86_64-linux and i686-linux. > > 2024-03-11 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/114278 > * tree-ssa.cc (maybe_optimize_var): If large/huge _BitInt vars are no > longer addressable, set DECL_NOT_GIMPLE_REG_P on them. > > * gcc.dg/bitint-99.c: New test. > > --- gcc/tree-ssa.cc.jj 2024-01-03 11:51:39.902615009 +0100 > +++ gcc/tree-ssa.cc 2024-03-09 23:34:12.469223987 +0100 > @@ -1785,6 +1785,20 @@ maybe_optimize_var (tree var, bitmap add > fprintf (dump_file, "\n"); > } > } > + else if (TREE_CODE (TREE_TYPE (var)) == BITINT_TYPE > + && (cfun->curr_properties & PROP_gimple_lbitint) != 0 > + && TYPE_PRECISION (TREE_TYPE (var)) > MAX_FIXED_MODE_SIZE) > + { > + /* Don't rewrite large/huge _BitInt vars after _BitInt lowering > + into SSA form. */ > + DECL_NOT_GIMPLE_REG_P (var) = 1; > + if (dump_file) > + { > + fprintf (dump_file, "_BitInt var after its lowering: "); > + print_generic_expr (dump_file, var); > + fprintf (dump_file, "\n"); > + } > + } > else if (DECL_NOT_GIMPLE_REG_P (var)) > { > maybe_reg = true; > --- gcc/testsuite/gcc.dg/bitint-99.c.jj 2024-03-08 14:26:17.658069942 +0100 > +++ gcc/testsuite/gcc.dg/bitint-99.c 2024-03-08 14:25:36.292645965 +0100 > @@ -0,0 +1,26 @@ > +/* PR tree-optimization/114278 */ > +/* { dg-do compile { target bitint } } */ > +/* { dg-options "-O2 -fno-tree-dce -fno-tree-dse -fno-tree-ccp" } */ > +/* { dg-additional-options "-mavx2" { target i?86-*-* x86_64-*-* } } */ > + > +void > +foo (void *p) > +{ > + _BitInt(64) b = *(_BitInt(64) *) __builtin_memmove (&b, p, sizeof (_BitInt(64))); > +} > + > +#if __BITINT_MAXWIDTH__ >= 128 > +void > +bar (void *p) > +{ > + _BitInt(128) b = *(_BitInt(128) *) __builtin_memmove (&b, p, sizeof (_BitInt(128))); > +} > +#endif > + > +#if __BITINT_MAXWIDTH__ >= 256 > +void > +baz (void *p) > +{ > + _BitInt(256) b = *(_BitInt(256) *) __builtin_memmove (&b, p, sizeof (_BitInt(256))); > +} > +#endif > > Jakub > >
On Mon, Mar 11, 2024 at 11:31:51AM +0100, Richard Biener wrote: > On Mon, 11 Mar 2024, Jakub Jelinek wrote: > > > On Sat, Mar 09, 2024 at 12:25:42PM +0100, Richard Biener wrote: > > > Ideally we?d clear TREE_ADDRESSABLE but set DECL_NOT_GIMPLE_REG, > > > I think the analysis where we check the base would be a more > > > appropriate place to enforce that. > > > > So like this? > > Hm, I was thinking of non_rewritable_lvalue_p/non_rewritable_mem_ref_base > though that requires duplicating, so I guess handling in maybe_optimize_var > would work. I was considering it, but it looked like a waste to me, using bitmap bits for something that is always the case, we don't want to rewrite any large/huge _BitInt to SSA form after the lowering, not just some of them. > I do now wonder whether setting DECL_NOT_GIMPLE_REG_P in bitfield > lowering would prevail? Guess I can certainly try to set DECL_NOT_GIMPLE_REG_P on the large/huge _BitInt PARM_DECLs/RESULT_DECLs during bitint lowering even when they are TREE_ADDRESSABLE at that point; the VAR_DECLs have array types of limbs and so shouldn't be a problem. > (sorry for approving the earlier patch now, I was too quick and didn't > remember the discussion) Sorry, already committed, I can revert or incrementally adjust. Jakub
On Mon, 11 Mar 2024, Jakub Jelinek wrote: > On Mon, Mar 11, 2024 at 11:31:51AM +0100, Richard Biener wrote: > > On Mon, 11 Mar 2024, Jakub Jelinek wrote: > > > > > On Sat, Mar 09, 2024 at 12:25:42PM +0100, Richard Biener wrote: > > > > Ideally we?d clear TREE_ADDRESSABLE but set DECL_NOT_GIMPLE_REG, > > > > I think the analysis where we check the base would be a more > > > > appropriate place to enforce that. > > > > > > So like this? > > > > Hm, I was thinking of non_rewritable_lvalue_p/non_rewritable_mem_ref_base > > though that requires duplicating, so I guess handling in maybe_optimize_var > > would work. > > I was considering it, but it looked like a waste to me, using bitmap bits > for something that is always the case, we don't want to rewrite any > large/huge _BitInt to SSA form after the lowering, not just some of them. > > > I do now wonder whether setting DECL_NOT_GIMPLE_REG_P in bitfield > > lowering would prevail? > > Guess I can certainly try to set DECL_NOT_GIMPLE_REG_P on the large/huge > _BitInt PARM_DECLs/RESULT_DECLs during bitint lowering even when they are > TREE_ADDRESSABLE at that point; the VAR_DECLs have array types of limbs and > so shouldn't be a problem. Hmm, looking I think we're going to clear DECL_NOT_GIMPLE_REG_P since we still have is_gimple_reg_type. > > (sorry for approving the earlier patch now, I was too quick and didn't > > remember the discussion) > > Sorry, already committed, I can revert or incrementally adjust. No problem, I think both patches are OK, the 2nd maybe a bit better for alias analysis. Richard.
--- gcc/tree-ssa.cc.jj 2024-01-03 11:51:39.902615009 +0100 +++ gcc/tree-ssa.cc 2024-03-09 23:34:12.469223987 +0100 @@ -1785,6 +1785,20 @@ maybe_optimize_var (tree var, bitmap add fprintf (dump_file, "\n"); } } + else if (TREE_CODE (TREE_TYPE (var)) == BITINT_TYPE + && (cfun->curr_properties & PROP_gimple_lbitint) != 0 + && TYPE_PRECISION (TREE_TYPE (var)) > MAX_FIXED_MODE_SIZE) + { + /* Don't rewrite large/huge _BitInt vars after _BitInt lowering + into SSA form. */ + DECL_NOT_GIMPLE_REG_P (var) = 1; + if (dump_file) + { + fprintf (dump_file, "_BitInt var after its lowering: "); + print_generic_expr (dump_file, var); + fprintf (dump_file, "\n"); + } + } else if (DECL_NOT_GIMPLE_REG_P (var)) { maybe_reg = true; --- gcc/testsuite/gcc.dg/bitint-99.c.jj 2024-03-08 14:26:17.658069942 +0100 +++ gcc/testsuite/gcc.dg/bitint-99.c 2024-03-08 14:25:36.292645965 +0100 @@ -0,0 +1,26 @@ +/* PR tree-optimization/114278 */ +/* { dg-do compile { target bitint } } */ +/* { dg-options "-O2 -fno-tree-dce -fno-tree-dse -fno-tree-ccp" } */ +/* { dg-additional-options "-mavx2" { target i?86-*-* x86_64-*-* } } */ + +void +foo (void *p) +{ + _BitInt(64) b = *(_BitInt(64) *) __builtin_memmove (&b, p, sizeof (_BitInt(64))); +} + +#if __BITINT_MAXWIDTH__ >= 128 +void +bar (void *p) +{ + _BitInt(128) b = *(_BitInt(128) *) __builtin_memmove (&b, p, sizeof (_BitInt(128))); +} +#endif + +#if __BITINT_MAXWIDTH__ >= 256 +void +baz (void *p) +{ + _BitInt(256) b = *(_BitInt(256) *) __builtin_memmove (&b, p, sizeof (_BitInt(256))); +} +#endif