From: Richard Sandiford <richard.sandiford@arm.com>
Date: Tue, 25 Feb 2020 19:20:58 +0000 (+0000)
Subject: optabs: Don't use scalar conversions for vectors [PR93843]
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=b6268016bf46dd63227dcbb73d13c30a3b4b9d2a;p=gcc.git

optabs: Don't use scalar conversions for vectors [PR93843]

In this PR we had a conversion between two integer vectors that
both had scalar integer modes.  We then tried to implement the
conversion using the scalar optab for those modes, instead of
doing the conversion elementwise.

I wondered about letting through scalar modes for single-element
vectors, but I don't have any evidence that that's useful/necessary,
so it seemed better to keep things simple.

2020-02-26  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	PR middle-end/93843
	* optabs-tree.c (supportable_convert_operation): Reject types with
	scalar modes.

gcc/testsuite/
	PR middle-end/93843
	* gcc.dg/vect/pr93843-1.c: New test.
	* gcc.dg/vect/pr93843-2.c: Likewise.
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7504b130222..c5b1eccb7d6 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-26  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR middle-end/93843
+	* optabs-tree.c (supportable_convert_operation): Reject types with
+	scalar modes.
+
 2020-02-26  David Malcolm  <dmalcolm@redhat.com>
 
 	* Makefile.in (ANALYZER_OBJS): Add analyzer/bar-chart.o.
diff --git a/gcc/optabs-tree.c b/gcc/optabs-tree.c
index 3d829c27826..badd30bfda8 100644
--- a/gcc/optabs-tree.c
+++ b/gcc/optabs-tree.c
@@ -284,9 +284,14 @@ supportable_convert_operation (enum tree_code code,
   machine_mode m1,m2;
   bool truncp;
 
+  gcc_assert (VECTOR_TYPE_P (vectype_out) && VECTOR_TYPE_P (vectype_in));
+
   m1 = TYPE_MODE (vectype_out);
   m2 = TYPE_MODE (vectype_in);
 
+  if (!VECTOR_MODE_P (m1) || !VECTOR_MODE_P (m2))
+    return false;
+
   /* First check if we can done conversion directly.  */
   if ((code == FIX_TRUNC_EXPR
        && can_fix_p (m1,m2,TYPE_UNSIGNED (vectype_out), &truncp)
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 35715adbe52..aa5d41e5559 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-26  Richard Sandiford  <richard.sandiford@arm.com>
+
+	PR middle-end/93843
+	* gcc.dg/vect/pr93843-1.c: New test.
+	* gcc.dg/vect/pr93843-2.c: Likewise.
+
 2020-02-26  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/93820
diff --git a/gcc/testsuite/gcc.dg/vect/pr93843-1.c b/gcc/testsuite/gcc.dg/vect/pr93843-1.c
new file mode 100644
index 00000000000..23a79ca4c96
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr93843-1.c
@@ -0,0 +1,21 @@
+char a;
+struct S { short b, c; } d;
+
+__attribute__((noipa)) void
+foo (int x)
+{
+  if (x != 4)
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  short *g = &d.c, *h = &d.b;
+  char e = 4 - a;
+  int f;
+  *h = *g = e;
+  for (f = 0; f < 2; f++)
+    foo (d.c);
+  return 0;
+}
diff --git a/gcc/testsuite/gcc.dg/vect/pr93843-2.c b/gcc/testsuite/gcc.dg/vect/pr93843-2.c
new file mode 100644
index 00000000000..5fae3e5be17
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/vect/pr93843-2.c
@@ -0,0 +1,11 @@
+char in[2] = {2, 2};
+short out[2] = {};
+
+int
+main()
+{
+  for (int i = 0; i < 2; ++i)
+    out[i] = in[i];
+  asm("":::"memory");
+  if (out[0] != 2) __builtin_abort();
+}