RE: [PATCH] PR tree-optimization/97546 Bail out of find_bswap_or_nop on non-INTEGER_CST sizes

[Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>]

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> -----Original Message-----
> From: Jakub Jelinek <jakub@redhat.com>
> Sent: 26 October 2020 09:32
> To: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>
> Cc: gcc-patches@gcc.gnu.org
> Subject: Re: [PATCH] PR tree-optimization/97546 Bail out of
> find_bswap_or_nop on non-INTEGER_CST sizes
> 
> On Mon, Oct 26, 2020 at 09:20:42AM +0000, Kyrylo Tkachov via Gcc-patches
> wrote:
> > This patch fixes the ICE in the PR by bailing out of find_bswap_or_nop on
> poly_int sizes.
> > I don't think it intends to handle them and from my reading of the code it's
> the most appropriate place to reject them
> > here rather than in the callers.
> >
> > Bootstrapped and tested on aarch64-none-linux-gnu.
> >
> > Ok for trunk?
> > Thanks,
> > Kyrill
> >
> > gcc/
> > 	PR tree-optimization/97546
> > 	* gimple-ssa-store-merging.c (find_bswap_or_nop): Return NULL if
> type is
> > 	not INTEGER_CST.
> 
> I think better use tree_fits_uhwi_p instead of cst_and_fits_hwi and
> instead of TREE_INT_CST_LOW use tree_to_uhwi.
> TYPE_SIZE_UNIT which doesn't fit into uhwi but fits into shwi is something
> that really shouldn't appear.
> Otherwise LGTM.

Thanks, that makes sense.
Is the attached patch ok?
Kyrill

> 
> > gcc/testsuite/
> > 	PR tree-optimization/97546
> > 	* gcc.target/aarch64/sve/acle/general/pr97546.c: New test.
> 
> 
> 
> 	Jakub


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diff --git a/gcc/gimple-ssa-store-merging.c b/gcc/gimple-ssa-store-merging.c
index 28fc2e2..d2a069f 100644
--- a/gcc/gimple-ssa-store-merging.c
+++ b/gcc/gimple-ssa-store-merging.c
@@ -851,12 +851,16 @@ find_bswap_or_nop_finalize (struct symbolic_number *n, uint64_t *cmpxchg,
 gimple *
 find_bswap_or_nop (gimple *stmt, struct symbolic_number *n, bool *bswap)
 {
+  tree type_size = TYPE_SIZE_UNIT (gimple_expr_type (stmt));
+  if (!tree_fits_uhwi_p  (type_size))
+    return NULL;
+
   /* The last parameter determines the depth search limit.  It usually
      correlates directly to the number n of bytes to be touched.  We
      increase that number by 2 * (log2(n) + 1) here in order to also
      cover signed -> unsigned conversions of the src operand as can be seen
      in libgcc, and for initial shift/and operation of the src operand.  */
-  int limit = TREE_INT_CST_LOW (TYPE_SIZE_UNIT (gimple_expr_type (stmt)));
+  int limit = tree_to_uhwi (type_size);
   limit += 2 * (1 + (int) ceil_log2 ((unsigned HOST_WIDE_INT) limit));
   gimple *ins_stmt = find_bswap_or_nop_1 (stmt, n, limit);
 
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr97546.c b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr97546.c
new file mode 100644
index 0000000..25707cd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/acle/general/pr97546.c
@@ -0,0 +1,22 @@
+/* { dg-options "-O2" } */
+
+#include <arm_sve.h>
+
+static svbool_t visinf_vo_vf(svfloat32_t d)
+{
+  return svcmpeq_n_f32 (svptrue_b8 (),
+                        svabs_f32_x (svptrue_b8 (), d),
+                        __builtin_inff ());
+}
+
+const svint32_t _ZGVsNxv_ilogbf(svfloat32_t d)
+{
+  svint32_t e = svreinterpret_s32_f32 (svdup_n_f32 (0.0f));
+  e = svsel_s32 (svcmpne_f32 (svptrue_b8(), d, d),
+                 svdup_n_s32 (2147483647),
+                 e);
+  e = svsel_s32 (visinf_vo_vf (d),
+                 svdup_n_s32 (0x7fffffff),
+                 e);
+  return e;
+}