Prathamesh Kulkarni <prathamesh.kulka...@linaro.org> writes:
> Hi,
> The following test:
>
> #include "arm_sve.h"
>
> svint8_t
> test_s8(int8_t *x)
> {
> return svld1rq_s8 (svptrue_b8 (), &x[0]);
> }
>
> ICE's with -march=armv8.2-a+sve -O1 -fno-tree-ccp -fno-tree-forwprop:
> during GIMPLE pass: fre
> pr107920.c: In function ‘test_s8’:
> pr107920.c:7:1: internal compiler error: in execute_todo, at passes.cc:2140
> 7 | }
> | ^
> 0x7b03d0 execute_todo
> ../../gcc/gcc/passes.cc:2140
>
> because of incorrect handling of virtual operands in svld1rq_impl::fold:
> # VUSE <.MEM>
> _5 = MEM <vector(16) signed char> [(signed char * {ref-all})x_3(D)];
> _4 = VEC_PERM_EXPR <_5, _5, { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
> 12, 13, 14, 15, ... }>;
> # VUSE <.MEM_2(D)>
> return _4;
>
> The attached patch tries to fix the issue by building the replacement
> statements in gimple_seq, and passing it to gsi_replace_with_seq_vops,
> which resolves the ICE, and results in:
> <bb 2> :
> # VUSE <.MEM_2(D)>
> _5 = MEM <vector(16) signed char> [(signed char * {ref-all})x_3(D)];
> _4 = VEC_PERM_EXPR <_5, _5, { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
> 12, 13, 14, 15, ... }>;
> # VUSE <.MEM_2(D)>
> return _4;
>
> Bootstrapped+tested on aarch64-linux-gnu.
> OK to commit ?
Looks good, but we also need to deal with the -fnon-call-exceptions
point that Andrew made in the PR trail. An easy way of testing
would be to make sure that:
#include "arm_sve.h"
svint8_t
test_s8(int8_t *x)
{
try
{
return svld1rq_s8 (svptrue_b8 (), &x[0]);
}
catch (...)
{
return svdup_s8 (1);
}
}
compiled with -fnon-call-exceptions still has a call to __cxa_begin_catch.
I don't think it's worth optimising this case. Let's just add
!flag_non_call_exceptions to the test.
The patch is missing a changelog btw.
Thanks,
Richard
> Thanks,
> Prathamesh
>
> diff --git a/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> index 6347407555f..f5546a65d22 100644
> --- a/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> +++ b/gcc/config/aarch64/aarch64-sve-builtins-base.cc
> @@ -45,6 +45,7 @@
> #include "aarch64-sve-builtins-base.h"
> #include "aarch64-sve-builtins-functions.h"
> #include "ssa.h"
> +#include "gimple-fold.h"
>
> using namespace aarch64_sve;
>
> @@ -1232,7 +1233,9 @@ public:
> tree mem_ref_op = fold_build2 (MEM_REF, access_type, arg1, zero);
> gimple *mem_ref_stmt
> = gimple_build_assign (mem_ref_lhs, mem_ref_op);
> - gsi_insert_before (f.gsi, mem_ref_stmt, GSI_SAME_STMT);
> +
> + gimple_seq stmts = NULL;
> + gimple_seq_add_stmt_without_update (&stmts, mem_ref_stmt);
>
> int source_nelts = TYPE_VECTOR_SUBPARTS (access_type).to_constant ();
> vec_perm_builder sel (lhs_len, source_nelts, 1);
> @@ -1245,8 +1248,11 @@ public:
> indices));
> tree mask_type = build_vector_type (ssizetype, lhs_len);
> tree mask = vec_perm_indices_to_tree (mask_type, indices);
> - return gimple_build_assign (lhs, VEC_PERM_EXPR,
> - mem_ref_lhs, mem_ref_lhs, mask);
> + gimple *g2 = gimple_build_assign (lhs, VEC_PERM_EXPR,
> + mem_ref_lhs, mem_ref_lhs, mask);
> + gimple_seq_add_stmt_without_update (&stmts, g2);
> + gsi_replace_with_seq_vops (f.gsi, stmts);
> + return g2;
> }
>
> return NULL;
> diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
> index c2d9c806aee..03cdb2f9f49 100644
> --- a/gcc/gimple-fold.cc
> +++ b/gcc/gimple-fold.cc
> @@ -591,7 +591,7 @@ fold_gimple_assign (gimple_stmt_iterator *si)
> If the statement has a lhs the last stmt in the sequence is expected
> to assign to that lhs. */
>
> -static void
> +void
> gsi_replace_with_seq_vops (gimple_stmt_iterator *si_p, gimple_seq stmts)
> {
> gimple *stmt = gsi_stmt (*si_p);
> diff --git a/gcc/gimple-fold.h b/gcc/gimple-fold.h
> index 7d29ee9a9a4..87ed4e56d25 100644
> --- a/gcc/gimple-fold.h
> +++ b/gcc/gimple-fold.h
> @@ -63,6 +63,7 @@ extern bool arith_code_with_undefined_signed_overflow
> (tree_code);
> extern gimple_seq rewrite_to_defined_overflow (gimple *, bool = false);
> extern void replace_call_with_value (gimple_stmt_iterator *, tree);
> extern tree tree_vec_extract (gimple_stmt_iterator *, tree, tree, tree,
> tree);
> +extern void gsi_replace_with_seq_vops (gimple_stmt_iterator *, gimple_seq);
>
> /* gimple_build, functionally matching fold_buildN, outputs stmts
> int the provided sequence, matching and simplifying them on-the-fly.
> diff --git a/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr107920.c
> b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr107920.c
> new file mode 100644
> index 00000000000..11448ed5e68
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr107920.c
> @@ -0,0 +1,10 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O1 -fno-tree-ccp -fno-tree-forwprop" } */
> +
> +#include "arm_sve.h"
> +
> +svint8_t
> +test_s8(int8_t *x)
> +{
> + return svld1rq_s8 (svptrue_b8 (), &x[0]);
> +}
