[PATCH] libstdc++: testsuite: require cmath for exp simd

[Alexandre Oliva <oliva@adacore.com>]

simd_math.h assumes declarations for many C99 functions to be present,
that libstdc++ doesn't add to target systems that don't have them in
the C library.

Add the C99 math requirement to tests for simd features, so that they
don't fail because of limitations of the target C library.

Regstrapped on x86_64-linux-gnu, also tested with a cross to
aarch64-rtems6.  Ok to install?


for  libstdc++-v3/ChangeLog

	* testsuite/experimental/simd/standard_abi_usable.cc: Require
	cmath support.
	* testsuite/experimental/simd/standard_abi_usable_2.cc:
	Likewise.
---
 .../experimental/simd/standard_abi_usable.cc       |    1 +
 .../experimental/simd/standard_abi_usable_2.cc     |    1 +
 2 files changed, 2 insertions(+)

diff --git a/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable.cc b/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable.cc
index 4d7e6726951fe..1b686d9ca095b 100644
--- a/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable.cc
+++ b/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable.cc
@@ -1,5 +1,6 @@
 // { dg-options "-std=c++17 -fno-fast-math" }
 // { dg-do compile { target c++17 } }
+// { dg-require-cmath "" }
 
 // Copyright (C) 2020-2022 Free Software Foundation, Inc.
 //
diff --git a/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable_2.cc b/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable_2.cc
index a609adaf000b3..a0203d0b4238d 100644
--- a/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable_2.cc
+++ b/libstdc++-v3/testsuite/experimental/simd/standard_abi_usable_2.cc
@@ -1,4 +1,5 @@
 // { dg-options "-std=c++17 -ffast-math" }
 // { dg-do compile }
+// { dg-require-cmath "" }
 
 #include "standard_abi_usable.cc"

-- 
Alexandre Oliva, happy hacker                https://FSFLA.org/blogs/lxo/
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts.  Ask me about <https://stallmansupport.org>