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* [gcc r13-6089] libstdc++: Ensure __builtin_constant_p isn't lost on the way
@ 2023-02-16 14:58 Matthias Kretz
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From: Matthias Kretz @ 2023-02-16 14:58 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:fea34ee491104f325682cc5fb75683b7d74a0a3b
commit r13-6089-gfea34ee491104f325682cc5fb75683b7d74a0a3b
Author: Matthias Kretz <m.kretz@gsi.de>
Date: Fri Jan 13 16:20:36 2023 +0100
libstdc++: Ensure __builtin_constant_p isn't lost on the way
The more expensive code path should only be taken if it can be optimized
away.
Signed-off-by: Matthias Kretz <m.kretz@gsi.de>
libstdc++-v3/ChangeLog:
* include/experimental/bits/simd.h
(_SimdWrapper::_M_is_constprop_none_of)
(_SimdWrapper::_M_is_constprop_all_of): Return false unless the
computed result still satisfies __builtin_constant_p.
Diff:
---
libstdc++-v3/include/experimental/bits/simd.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/include/experimental/bits/simd.h b/libstdc++-v3/include/experimental/bits/simd.h
index e76f4781fa6..3de966bbf22 100644
--- a/libstdc++-v3/include/experimental/bits/simd.h
+++ b/libstdc++-v3/include/experimental/bits/simd.h
@@ -2673,7 +2673,8 @@ template <typename _Tp, size_t _Width>
else
__execute_n_times<_Width>(
[&](auto __i) { __r &= _M_data[__i.value] == _Tp(); });
- return __r;
+ if (__builtin_constant_p(__r))
+ return __r;
}
return false;
}
@@ -2693,7 +2694,8 @@ template <typename _Tp, size_t _Width>
else
__execute_n_times<_Width>(
[&](auto __i) { __r &= _M_data[__i.value] == ~_Tp(); });
- return __r;
+ if (__builtin_constant_p(__r))
+ return __r;
}
return false;
}
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