[aarch64] PR target/94591: Don't generate invalid REV64 insns

This fixes PR94591. The problem was the function aarch64_evpc_rev_local()
matching vector permutations that were not reversals. In particular, prior to
this patch, this function matched the identity permutation which led to
generating bogus REV64 insns which were rejected by the assembler.

gcc/
	PR target/94591
	* config/aarch64/aarch64.c (aarch64_evpc_rev_local): Don't match
	identity permutation.

gcc/testsuite/
	PR target/94591
	* gcc.c-torture/execute/pr94591.c: New test.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 703b634..9eee988 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-05-19  Alex Coplan  <alex.coplan@arm.com>
+
+       PR target/94591
+       * config/aarch64/aarch64.c (aarch64_evpc_rev_local): Don't match
+       identity permutation.
+
 2020-05-19  Jozef Lawrynowicz  <jozef.l@mittosystems.com>
 
        * doc/sourcebuild.texi: Document new short_eq_int, ptr_eq_short,

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 70aa2f7..79c016f 100644 (file)
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -20191,7 +20191,8 @@ aarch64_evpc_rev_local (struct expand_vec_perm_d *d)
 
   if (d->vec_flags == VEC_SVE_PRED
       || !d->one_vector_p
-      || !d->perm[0].is_constant (&diff))
+      || !d->perm[0].is_constant (&diff)
+      || !diff)
     return false;
 
   size = (diff + 1) * GET_MODE_UNIT_SIZE (d->vmode);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0e54d39..48671f1 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-05-19  Alex Coplan  <alex.coplan@arm.com>
+
+       PR target/94591
+       * gcc.c-torture/execute/pr94591.c: New test.
+
 2020-05-19  Nathan Sidwell  <nathan@acm.org>
 
        * c-c++-common/raw-string-14.c: Adjust errors.

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr94591.c b/gcc/testsuite/gcc.c-torture/execute/pr94591.c
new file mode 100644 (file)
index 0000000..42271ad
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr94591.c
@@ -0,0 +1,32 @@
+typedef unsigned __attribute__((__vector_size__(8))) V2SI_u;
+typedef int __attribute__((__vector_size__(8))) V2SI_d;
+
+typedef unsigned long __attribute__((__vector_size__(16))) V2DI_u;
+typedef long __attribute__((__vector_size__(16))) V2DI_d;
+
+void id_V2SI(V2SI_d *v)
+{
+  *v = __builtin_shuffle(*v, (V2SI_d)(V2SI_u) { 0, 1 });
+}
+
+void id_V2DI(V2DI_d *v)
+{
+  *v = __builtin_shuffle(*v, (V2DI_d)(V2DI_u) { 0, 1 });
+}
+
+extern void abort(void);
+
+int main(void)
+{
+  V2SI_d si = { 35, 42 };
+  id_V2SI(&si);
+
+  if (si[0] != 35 || si[1] != 42)
+    abort();
+
+  V2DI_d di = { 63, 38 };
+  id_V2DI(&di);
+
+  if (di[0] != 63 || di[1] != 38)
+    abort();
+}