From 5da301cbd81c41b2e9629f55dd1b1889f7dae75e Mon Sep 17 00:00:00 2001
From: Richard Sandiford <richard.sandiford@arm.com>
Date: Mon, 20 Apr 2020 15:43:32 +0100
Subject: [PATCH] aarch64: Fix vector builds used by SVE vec_init [PR94668]
This testcase triggered an ICE in rtx_vector_builder::step because
we were trying to use a stepped representation for floating-point
constants. The underlying problem was that the arguments to
rtx_vector_builder were the wrong way around, meaning that some
variations were likely to be incorrectly encoded for integers
(but probably as a silent failure).
Also, aarch64_sve_expand_vector_init_handle_trailing_constants
tries to extend the trailing constant elements to a full vector
by following the "natural" pattern of the original vector, which
should generally lead to nicer constants. However, for the testcase,
we'd then end up picking a variable for some elements. Fixed by
stubbing out all variable elements with zeros.
That fix involved testing valid_for_const_vector_p. For consistency,
the patch uses the same test when finding trailing constants, instead
of the previous aarch64_legitimate_constant_p.
2020-04-20 Richard Sandiford <richard.sandiford@arm.com>
gcc/
PR target/94668
* config/aarch64/aarch64.c (aarch64_sve_expand_vector_init): Fix
order of arguments to rtx_vector_builder.
(aarch64_sve_expand_vector_init_handle_trailing_constants): Likewise.
When extending the trailing constants to a full vector, replace any
variables with zeros.
gcc/testsuite/
PR target/94668
* gcc.target/aarch64/sve/pr94668.c: New test.
---
gcc/ChangeLog | 9 +++++++
gcc/config/aarch64/aarch64.c | 26 ++++++++++++++-----
gcc/testsuite/ChangeLog | 5 ++++
.../gcc.target/aarch64/sve/pr94668.c | 8 ++++++
4 files changed, 41 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/sve/pr94668.c
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cc6c6389b902..4c9de79c1fd5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2020-04-20 Richard Sandiford <richard.sandiford@arm.com>
+
+ PR target/94668
+ * config/aarch64/aarch64.c (aarch64_sve_expand_vector_init): Fix
+ order of arguments to rtx_vector_builder.
+ (aarch64_sve_expand_vector_init_handle_trailing_constants): Likewise.
+ When extending the trailing constants to a full vector, replace any
+ variables with zeros.
+
2020-04-20 Jan Hubicka <hubicka@ucw.cz>
PR ipa/94582
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 24c055df0dcb..ee6a2de77a59 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -18382,15 +18382,27 @@ aarch64_sve_expand_vector_init_handle_trailing_constants
int n_trailing_constants = 0;
for (int i = nelts_reqd - 1;
- i >= 0 && aarch64_legitimate_constant_p (elem_mode, builder.elt (i));
+ i >= 0 && valid_for_const_vector_p (elem_mode, builder.elt (i));
i--)
n_trailing_constants++;
if (n_trailing_constants >= nelts_reqd / 2)
{
- rtx_vector_builder v (mode, 1, nelts);
+ /* Try to use the natural pattern of BUILDER to extend the trailing
+ constant elements to a full vector. Replace any variables in the
+ extra elements with zeros.
+
+ ??? It would be better if the builders supported "don't care"
+ elements, with the builder filling in whichever elements
+ give the most compact encoding. */
+ rtx_vector_builder v (mode, nelts, 1);
for (int i = 0; i < nelts; i++)
- v.quick_push (builder.elt (i + nelts_reqd - n_trailing_constants));
+ {
+ rtx x = builder.elt (i + nelts_reqd - n_trailing_constants);
+ if (!valid_for_const_vector_p (elem_mode, x))
+ x = const0_rtx;
+ v.quick_push (x);
+ }
rtx const_vec = v.build ();
emit_move_insn (target, const_vec);
@@ -18508,7 +18520,7 @@ aarch64_sve_expand_vector_init (rtx target, const rtx_vector_builder &builder,
/* Case 2: Vector contains leading constants. */
- rtx_vector_builder rev_builder (mode, 1, nelts_reqd);
+ rtx_vector_builder rev_builder (mode, nelts_reqd, 1);
for (int i = 0; i < nelts_reqd; i++)
rev_builder.quick_push (builder.elt (nelts_reqd - i - 1));
rev_builder.finalize ();
@@ -18541,8 +18553,8 @@ aarch64_sve_expand_vector_init (rtx target, const rtx_vector_builder &builder,
if (nelts_reqd <= 4)
return false;
- rtx_vector_builder v_even (mode, 1, nelts);
- rtx_vector_builder v_odd (mode, 1, nelts);
+ rtx_vector_builder v_even (mode, nelts, 1);
+ rtx_vector_builder v_odd (mode, nelts, 1);
for (int i = 0; i < nelts * 2; i += 2)
{
@@ -18586,7 +18598,7 @@ aarch64_sve_expand_vector_init (rtx target, rtx vals)
machine_mode mode = GET_MODE (target);
int nelts = XVECLEN (vals, 0);
- rtx_vector_builder v (mode, 1, nelts);
+ rtx_vector_builder v (mode, nelts, 1);
for (int i = 0; i < nelts; i++)
v.quick_push (XVECEXP (vals, 0, i));
v.finalize ();
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9ba21a0b7f83..9bf3581b7700 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-20 Richard Sandiford <richard.sandiford@arm.com>
+
+ PR target/94668
+ * gcc.target/aarch64/sve/pr94668.c: New test.
+
2020-04-20 Jan Hubicka <hubicka@ucw.cz>
PR ipa/94582
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr94668.c b/gcc/testsuite/gcc.target/aarch64/sve/pr94668.c
new file mode 100644
index 000000000000..9ff01e825c94
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr94668.c
@@ -0,0 +1,8 @@
+/* { dg-options "-O -msve-vector-bits=512" } */
+
+typedef float v16sf __attribute__ ((vector_size(64)));
+v16sf
+foo (float a)
+{
+ return (v16sf) { 0, 0, 0, a, 0, 0, 0, 0, 0, a, 0, 0, 0, 0, 0, 0 };
+}
--
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