Message ID | alpine.LSU.2.20.1704061438350.30715@zhemvz.fhfr.qr |
---|---|
State | New |
Headers | show |
Hi Richard, > The following patch makes sure to preserve (mis-)alignment of memory > references when IVOPTs generates TARGET_MEM_REFs for them. > > Bootstrapped on x86_64-unknown-linux-gnu, testing in progress. > > Richard. > > 2017-04-06 Richard Biener <rguenther@suse.de> > > PR tree-optimization/80334 > * tree-ssa-loop-ivopts.c (rewrite_use_address): Properly > preserve alignment of accesses. > > * g++.dg/torture/pr80334.C: New testcase. the new testcase FAILs on 32-bit Solaris/SPARC: +FAIL: g++.dg/torture/pr80334.C -O0 (test for excess errors) +FAIL: g++.dg/torture/pr80334.C -O1 (test for excess errors) +FAIL: g++.dg/torture/pr80334.C -O2 (test for excess errors) +FAIL: g++.dg/torture/pr80334.C -O2 -flto (test for excess errors) +FAIL: g++.dg/torture/pr80334.C -O2 -flto -flto-partition=none (test for exce ss errors) +FAIL: g++.dg/torture/pr80334.C -O3 -fomit-frame-pointer -funroll-loops -fpeel -loops -ftracer -finline-functions (test for excess errors) +FAIL: g++.dg/torture/pr80334.C -O3 -g (test for excess errors) +FAIL: g++.dg/torture/pr80334.C -Os (test for excess errors) Excess errors: /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/pr80334.C:11:20: warning: requested alignment 16 is larger than 8 [-Wattributes] Rainer
On Thu, 6 Apr 2017, Rainer Orth wrote: > Hi Richard, > > > The following patch makes sure to preserve (mis-)alignment of memory > > references when IVOPTs generates TARGET_MEM_REFs for them. > > > > Bootstrapped on x86_64-unknown-linux-gnu, testing in progress. > > > > Richard. > > > > 2017-04-06 Richard Biener <rguenther@suse.de> > > > > PR tree-optimization/80334 > > * tree-ssa-loop-ivopts.c (rewrite_use_address): Properly > > preserve alignment of accesses. > > > > * g++.dg/torture/pr80334.C: New testcase. > > the new testcase FAILs on 32-bit Solaris/SPARC: > > +FAIL: g++.dg/torture/pr80334.C -O0 (test for excess errors) > +FAIL: g++.dg/torture/pr80334.C -O1 (test for excess errors) > +FAIL: g++.dg/torture/pr80334.C -O2 (test for excess errors) > +FAIL: g++.dg/torture/pr80334.C -O2 -flto (test for excess errors) > +FAIL: g++.dg/torture/pr80334.C -O2 -flto -flto-partition=none (test for exce > ss errors) > +FAIL: g++.dg/torture/pr80334.C -O3 -fomit-frame-pointer -funroll-loops -fpeel > -loops -ftracer -finline-functions (test for excess errors) > +FAIL: g++.dg/torture/pr80334.C -O3 -g (test for excess errors) > +FAIL: g++.dg/torture/pr80334.C -Os (test for excess errors) > > Excess errors: > /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/pr80334.C:11:20: warning: requested alignment 16 is larger than 8 [-Wattributes] Any suggestion how to mitigate that? Possible solution includes adding { target { ! ... } } to dg-do run. Richard.
Hi Richard, > On Thu, 6 Apr 2017, Rainer Orth wrote: > >> Hi Richard, >> >> > The following patch makes sure to preserve (mis-)alignment of memory >> > references when IVOPTs generates TARGET_MEM_REFs for them. >> > >> > Bootstrapped on x86_64-unknown-linux-gnu, testing in progress. >> > >> > Richard. >> > >> > 2017-04-06 Richard Biener <rguenther@suse.de> >> > >> > PR tree-optimization/80334 >> > * tree-ssa-loop-ivopts.c (rewrite_use_address): Properly >> > preserve alignment of accesses. >> > >> > * g++.dg/torture/pr80334.C: New testcase. >> >> the new testcase FAILs on 32-bit Solaris/SPARC: >> >> +FAIL: g++.dg/torture/pr80334.C -O0 (test for excess errors) >> +FAIL: g++.dg/torture/pr80334.C -O1 (test for excess errors) >> +FAIL: g++.dg/torture/pr80334.C -O2 (test for excess errors) >> +FAIL: g++.dg/torture/pr80334.C -O2 -flto (test for excess errors) >> +FAIL: g++.dg/torture/pr80334.C -O2 -flto -flto-partition=none (test for >> exce >> ss errors) >> +FAIL: g++.dg/torture/pr80334.C -O3 -fomit-frame-pointer -funroll-loops >> -fpeel >> -loops -ftracer -finline-functions (test for excess errors) >> +FAIL: g++.dg/torture/pr80334.C -O3 -g (test for excess errors) >> +FAIL: g++.dg/torture/pr80334.C -Os (test for excess errors) >> >> Excess errors: >> /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/pr80334.C:11:20: >> warning: requested alignment 16 is larger than 8 [-Wattributes] > > Any suggestion how to mitigate that? Possible solution includes > adding { target { ! ... } } to dg-do run. No idea. However, according to gcc-testresults there are other failures: s390-ibm-inux-gnu and s390x-ibm-linux-gnu so far. This might argue against just excluding a random list of failing targets. Rainer
On Fri, 7 Apr 2017, Rainer Orth wrote: > Hi Richard, > > > On Thu, 6 Apr 2017, Rainer Orth wrote: > > > >> Hi Richard, > >> > >> > The following patch makes sure to preserve (mis-)alignment of memory > >> > references when IVOPTs generates TARGET_MEM_REFs for them. > >> > > >> > Bootstrapped on x86_64-unknown-linux-gnu, testing in progress. > >> > > >> > Richard. > >> > > >> > 2017-04-06 Richard Biener <rguenther@suse.de> > >> > > >> > PR tree-optimization/80334 > >> > * tree-ssa-loop-ivopts.c (rewrite_use_address): Properly > >> > preserve alignment of accesses. > >> > > >> > * g++.dg/torture/pr80334.C: New testcase. > >> > >> the new testcase FAILs on 32-bit Solaris/SPARC: > >> > >> +FAIL: g++.dg/torture/pr80334.C -O0 (test for excess errors) > >> +FAIL: g++.dg/torture/pr80334.C -O1 (test for excess errors) > >> +FAIL: g++.dg/torture/pr80334.C -O2 (test for excess errors) > >> +FAIL: g++.dg/torture/pr80334.C -O2 -flto (test for excess errors) > >> +FAIL: g++.dg/torture/pr80334.C -O2 -flto -flto-partition=none (test for > >> exce > >> ss errors) > >> +FAIL: g++.dg/torture/pr80334.C -O3 -fomit-frame-pointer -funroll-loops > >> -fpeel > >> -loops -ftracer -finline-functions (test for excess errors) > >> +FAIL: g++.dg/torture/pr80334.C -O3 -g (test for excess errors) > >> +FAIL: g++.dg/torture/pr80334.C -Os (test for excess errors) > >> > >> Excess errors: > >> /vol/gcc/src/hg/trunk/local/gcc/testsuite/g++.dg/torture/pr80334.C:11:20: > >> warning: requested alignment 16 is larger than 8 [-Wattributes] > > > > Any suggestion how to mitigate that? Possible solution includes > > adding { target { ! ... } } to dg-do run. > > No idea. However, according to gcc-testresults there are other > failures: s390-ibm-inux-gnu and s390x-ibm-linux-gnu so far. > > This might argue against just excluding a random list of failing targets. Hmm. Does using __BIGGEST_ALIGNMENT__, thus int main() { alignas(__BIGGEST_ALIGNMENT__) B b[3]; ... work for you? Richard.
Hi Richard, >> > Any suggestion how to mitigate that? Possible solution includes >> > adding { target { ! ... } } to dg-do run. >> >> No idea. However, according to gcc-testresults there are other >> failures: s390-ibm-inux-gnu and s390x-ibm-linux-gnu so far. >> >> This might argue against just excluding a random list of failing targets. > > Hmm. Does using __BIGGEST_ALIGNMENT__, thus > > int > main() > { > alignas(__BIGGEST_ALIGNMENT__) B b[3]; > ... > > work for you? it does: the test now PASSes on sparc-sun-solaris2.12 and continues to do so in i386-pc-solaris2.12, both 32 and 64-bit. Thanks. Rainer
Index: gcc/tree-ssa-loop-ivopts.c =================================================================== --- gcc/tree-ssa-loop-ivopts.c (revision 246724) +++ gcc/tree-ssa-loop-ivopts.c (working copy) @@ -7396,7 +7396,11 @@ rewrite_use_address (struct ivopts_data base_hint = var_at_stmt (data->current_loop, cand, use->stmt); iv = var_at_stmt (data->current_loop, cand, use->stmt); - ref = create_mem_ref (&bsi, TREE_TYPE (*use->op_p), &aff, + tree type = TREE_TYPE (*use->op_p); + unsigned int align = get_object_alignment (*use->op_p); + if (align != TYPE_ALIGN (type)) + type = build_aligned_type (type, align); + ref = create_mem_ref (&bsi, type, &aff, reference_alias_ptr_type (*use->op_p), iv, base_hint, data->speed); copy_ref_info (ref, *use->op_p); Index: gcc/testsuite/g++.dg/torture/pr80334.C =================================================================== --- gcc/testsuite/g++.dg/torture/pr80334.C (nonexistent) +++ gcc/testsuite/g++.dg/torture/pr80334.C (working copy) @@ -0,0 +1,18 @@ +// { dg-do run } + +struct A { alignas(16) char c; }; +struct B { A unpacked; char d; } __attribute__((packed)); + +char x; + +int +main() +{ + alignas(16) B b[3]; + for (int i = 0; i < 3; i++) b[i].unpacked.c = 'a' + i; + for (int i = 0; i < 3; i++) + { + auto a = new A(b[i].unpacked); + x = a->c; + } +}