From: Richard Sandiford <richard.sandiford@arm.com>
Date: Thu, 13 Mar 2025 15:13:00 +0000 (+0000)
Subject: testsuite: Fix sve/mask_struct_load_3_run.c [PR113965]
X-Git-Tag: basepoints/gcc-16~1516
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=df87b300bd13ed047b1159022c93445f130458e6;p=thirdparty%2Fgcc.git

testsuite: Fix sve/mask_struct_load_3_run.c [PR113965]

Among other things, this testcase tests an addition of the four
values (n*4+[0:3])*9//2 for each n in [0:99].  The addition is
done in multiple integer and floating-point types and the test
is compiled with -ffast-math.

One of the floating-point types is _Float16, and as Andrew says
in the PR, _Float16's limited precision means that the order of the
additions begins to matter for higher n.  Specifically, some orders
begin to give different results from others at n=38, and at many
higher n as well.

This patch uses 5/3 rather than 9/2.  I tested locally that
all addition orders give the same result over the test range.

gcc/testsuite/
	PR testsuite/113965
	* gcc.target/aarch64/sve/mask_struct_load_3_run.c: Use an
	input range that is suitable for _Float16.
---

diff --git a/gcc/testsuite/gcc.target/aarch64/sve/mask_struct_load_3_run.c b/gcc/testsuite/gcc.target/aarch64/sve/mask_struct_load_3_run.c
index 8bc3b08fcf4..c0a7416cfaf 100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/mask_struct_load_3_run.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/mask_struct_load_3_run.c
@@ -18,7 +18,7 @@
 	asm volatile ("" ::: "memory");			\
       }							\
     for (int i = 0; i < N * 4; ++i)			\
-      in[i] = i * 9 / 2;				\
+      in[i] = i * 5 / 3;				\
     NAME##_4 (out, in, mask, N);			\
     for (int i = 0; i < N; ++i)				\
       {							\